ALBERT

Notes: Summary The eyes of Rostanga pulchra larvae develop immediately behind the velar lobes approximately 20 days after hatching. Each is a pigmented cup with a lens occupying the concavity of the cup. The eye is composed of a single corneal cell, 7 sensory cells and 8 pigment cells. Sensory cells are of the rhabdomeric type and bear microvilli as their receptive surface. The eye connects to the inner dorsal region of the optic ganglion through a nerve that consists of axons arising from the 7 sensory cells. The optic ganglion, in turn, joins the lateral region of the cerebral ganglion. The possible functions of the eye are discussed in relation to larval behavior.

Notes: Summary The small cells of the midgut glands of Armadillidium vulgare, Oniscus asellus, Porcellio scaber, and Alloniscus oahuensis were examined by transmission electron microscopy, X-ray microanalysis, histochemistry, and atomic absorption spectroscopy. Inclusions containing large amounts of heavy metals were the most prominent feature of these cells. Various areas of the midgut glands exhibited large differences in storage capacity. Juveniles were free of lead.

Notes: Summary The oesophageal epithelium of eleven sea-water and four fresh-water teleosts was studied by light and electron microscopy. In sea-water species, the three main regions from pharynx to stomach are: a thick stratified pharyngeal epithelium with complex foldings and numerous mucous cells, and a simple microvillous columnar epithelium in the middle and posterior part. In fresh-water species, foldings are simple, the first two regions occupy the whole length, and no microvillous epithelium is observed. The adaptation from fresh-water to sea-water is characterized by the development of the third, microvillous epithelium. Different microridge cells appear in the mucous region of fresh-water and sea-water Anguilla anguilla oesophagus. The ultrastructure of the microvillous epithelium suggests an active transport of ions along the lateral membranes with water recycling in frequently dilated intercellular spaces.

Notes: Summary The cricket Cycloptiloides canariensis (Gryllidae, Mogoplistinae) has compound eyes of the eucone apposition type. They consist of relatively few (about 160–190) ommatidia with a wide angle of divergence. Each ommatidium has two primary pigment cells, four Semper cells and eight retinula cells whose four distal rhabdomeres are arranged around the tip of the crystalline cone. The screening pigments are contained mainly in the primary pigment and retinula cells, while the secondary pigment cells are sparsely pigmented. The dorsal eye region can be distinguished by the following characteristics: lack of dioptric apparatus (flat, unfacetted cornea, absence of cones), densely packed rhabdomes in approximately parallel orientation extending distally to the cornea and possessing a markedly increased cross-sectional area in comparison with those of normal ommatidia. Screening pigments are absent. The importance of this dorsal region will be discussed.

Notes: Summary The pore plates of Pimpla are about 40–75 μm long and 5–7 μm wide. Through a central cuticular canal they are in contact with the lumen of the antennae. Under the perforated plate blind-ending tunnels extend in the distal and proximal directions. It is extremely probable, that the pore plates of Hymenoptera are derivatives of basiconical sensilla. The ontogeny of the pore plates was followed back to the beginning of the deposition of the cuticulin layer. Each pore plate ‘anlage’ contains 40–47 sensory cells and 6 enveloping cells. Envelope cell 1 secretes the dendritic sheath, which is fully reduced during ontogeny. The envelope cells 2a and b (trichogen cells) are mirror images of each other, they form the perforated plate and the pore tubules. On both sides of the trichogen cells lie the envelope cells 3a and b (tormogen cells), they also form mirror images of each other. The tormogen cells secrete a cuticular ledge, that surrounds the perforated plate. In the outer distal position lies envelope cell 4, which encircles the pore plate ‘anlage’ in the proximal direction. Envelope cell 4 folds in and retreats from the epithelium surface, thus forming a ‘joint-furrow’ around the pore plate ‘anlage’. The doubling of the trichogen cell is unusual in insects and so far has been observed in basiconic sensilla and pore plates of Hymenoptera only. The doubling of the tormogen cell until now could be established only in basiconic sensilla of Cephus and of Xiphydria (Hymenoptera, Symphyta). In pupae 3–4 days old the trichogen and tormogen cells begin to retreat from the perforated plate. In the imago this outer receptor lymph cavity is nearly completely filled by the branched outer dendritic segments.

Notes: Summary During each moult the anal glands in Rhapidostreptus virgator are partly dissolved and subsequently rebuilt and enlarged by embryonic cells within the anal sac epithelium. An embryonic cell undergoes two mitoses thus producing the four cells which are present in a glandular unit. During the genesis of the glandular units each of the latter secretory cells produce a ciliary process, which is believed to serve as a mould for the canal cell, which in turn secretes the cuticular efferent duct.

Notes: Summary The fertilized egg of the freshwater bryozoan Plumatella fungosa develops into an elongated ovoid larva, which after embryogenesis in the embryo sack is released into the surrounding water. During the short free-swimming stage the larva is characterized by the presence of several locomotive and attachment cell types. The ectodermal epithelial cells are provided with numerous cilia. The cytoplasm of the epithelial cells contains numerous mitochondria, Golgi bodies, and ribosomes. Gland cells containing vacuoles of flocculent, lightly staining secretion material were observed between the epithelial cells in the anterior pole of the larva. From a neural center beneath the epidermal cells in the anterior pole nerves emerge in a radial direction. These nerves may include up to 30 axons. Beneath the nerves are a lamella of collagenous fibers and a layer of muscle cells. Internally the larva possesses a coelomic cavity bounded by a squamous epithelium. At the anterior pole large, irregular cells rich in rough endoplasmic reticulum and lipid droplets are seen associated with the coelomic wall. It is concluded that the P. fungosa larva is a true planctonic larva, although highly modified and reduced. There is an acceleration of adult features with differentiation of functional zooids within the larval body. This acceleration may be an adaptation to life in freshwater.

Notes: Summary Origin and formation of the body wall epidermis of the ancestrula in three species of gymnolaemate bryozoans were analyzed by scanning and transmission electron microscopy. In the ctenostome Bowerbankia gracilis, the aboral pallial epithelium forms the entire cystid epidermis, whereas in the anascan cheilostome Bugula neritina, the wall and roof regions of the internal sac form the epidermis. In the ascophoran cheilostome Watersipora culcullata, however, both the pallial epithelium and internal sac contribute to the body wall epidermis. In spite of these different origins, the tissues involved in production of the exoskeleton share a common ultrastructure. The various patterns of metamorphosis described here indicate that ancestrular body wall origin may be an important character in the analysis of phylogenetic relationships within the Bryozoa.

Notes: Summary The three anterior adhesive papillae of Diplosoma macdonaldi serve to attach the larva to the substratum at settlement. Each is a cup-shaped, epidermal organ with a bulbous axial protrusion. Approximately 50 sensory neurons (anchor cells) are distributed around the rim of each papillar cup within the epithelium. An axon from each passes within the wall of the cup to the base of the papilla and thence in the hemocoel to the visceral ganglion. Microvilli arising from anchor cells form a network below the outer cuticle of the tunic. Ten to 15 sensory neurons of a second type (basal cells) are situated within the epithelium around the base of each papilla. A single cilium arises from an invagination in the soma of each basal cell and extends either proximally or distally along the surface of the epithelium. An axon from each basal cell joins the anchor cell axons to project to the visceral ganglion. We infer that papillar sensory cells allow a larva to sample the characteristics of the substrate at potential sites for settlement and metamorphosis.

Notes: Summary Each sessile eye comprises about 60 ommatidia with large lenses (diameter 100–150 μm), spherical crystalline cones, and hypertrophied rhabdoms (diameter about 100 μm). The cones are formed by two main cone cells, and in addition two accessory cone cells are present. Seven retinula cells contribute to the rhabdom, which is fused distally and open proximally (separated rhabdomeres). A special cell type, previously designated ‘hyaline cells’ are shown to be reflecting pigment cells. These cells form a well-developed tapetal layer. Distal pigment cells screen neighbouring ommatidia. Further, the eye is delimited by two membranes homologous to the fenestrated and eye capsule membranes present in several other isopod groups. The hypertrophied rhabdoms and the elaborate tapetal layer separate the morphology of the Cirolana eye from that of other isopod eyes. These structural features makes the Cirolana eye a case of convergent development with several other deep water living crustaceans.

Notes: Summary The lateral retinae of some advanced salticid spiders are found to conform to the ultrastructural descriptions of Eakin and Brandenburger (1971). Retinae of two forms supposed by taxonomists to be primitive, Portia and Lyssomanes, are described for the first time. Portia exhibits the overall relationships between pigmented and non-pigmented glial processes and receptors typical of advanced forms, but (i) non-pigmented processes are elaborately and irregularly divided and do not contain microtubules; (ii) four pigmented processes enclose the complex of receptor+non pigmented glial processes instead of six. The rhabdomeral layer of the retina of Lyssomanes is not invaded by processes of the pigmented glia, which forms a pigmented screen proximal to the receptive segments. The receptors are separated from each other by thin lamellae of non-pigmented glia whose somata lie in the normal position amongst those of the receptors. The retinal organisation resembles that of some nocturnal spiders such as Menneus (Blest et al. 1980). The posterior median retinae of Portia are identical in construction to those of the other accessory eyes, although smaller. Those of Lyssomanes and advanced salticids are vestigial. Shedding of photoreceptor membrane during turnover appears to be largely intracellular in all these forms, in contrast to Plexippus in which an extracellular route has been described.

Notes: Summary The terminal organ, a structure enabling pelagosphera larvae of Sipuncula to form temporary attachments to substrata, was examined behaviorally and with light and electron microscopy for larvae of Golfingia misakiana, collected from the Florida Current. The terminal organ appears as a retractile rounded knob with a short neck joining the posterior extremity of the trunk. It can attach larvae directly to substratum or can secrete a tether-like mucus strand about which the organism moves. In unattached larvae, the terminal organ is often placed in the mouth. The terminal organ of a 5.5 day old larva consists of 29 cells: 8 epidermal, 3 mucus, 2 tension-bearing, 5 sensory, 10 retractor muscles and 1 unknown cell. The mucus cells are presumed to release the adhesive material while the microvilli on the tension-bearing cells, with their dense cores of microfilaments, bear the strain. The latter are joined directly to the retractor muscles which originate on the dorsal body wall near the anus. Two of the sensory cells terminate within the cuticle flanking the adhesive pore and are assumed to be cuticle strain receptors. Three sensory cells terminate in cilia that extend posteriorly from the pore. These may function in substratum evaluation prior to temporary attachment, or settlement preceding metamorphosis. The terminal organ is compared to adhesive organs in other soft-bodied metazoans and although it approximates the structure found in some rotifers, it is considered to be independently evolved within the Sipuncula. The terminal organ can be understood as an adaptation in young larvae for protective attachment and facilitation of feeding whereas, in older larvae, it may only function in substrate evaluation prior to settlement.

Notes: Summary Crinoid tube feet occur in groups of three (podial triplets) that behave as functionally integrated units for food particle collection. Scanning electron microscopy shows that each triplet member has a distinctive morphology related to its behavioural role in feeding. Particularly conspicuous features are papillar distribution, papillar processes, ciliary tracts, and pores that are the openings of mucous glands. The primary podia serve for initial particle capture. The secondaries, together with lappets, play a major role in particle transfer from the primaries and may themselves also entrap particles. The tertiaries manipulate particles within the food groove after their transfer from the other podia. The tertiary podia use their papilla-free medial faces to compact mucusbound particles into boluses. In pinnules, boluses are transferred to the food groove midline by tertiaries, then propelled orally by paddling actions of these podia. Boluses are also transported by the medial ciliary tracts of the pinnules and arms. Bolus transport by tertiary paddling is probably more effective in the pinnular than the arm food groove. Short lateral ciliary tracts at the base of each primary podium may guide boluses into the main ciliary stream or may be cleansing currents. As the ultimate site of food particle collection, compaction and transfer, podial triplets represent a third adaptive level of an intricate suspension feeding system in which the first (arm postures) and second (pinnule orientations) adaptive levels are related to increasing collecting efficiency in diverse ambient flow.

Notes: Summary The accessory eye of an African giant snail, Achatina fulica, is situated under an extension of the cornea of the main eye and invariably possesses a small lens. The accessory retina is composed of type I and type II sensory cells and nonpigmented supportive cells that closely resemble corneal cells. Type I cells contain photic vesicles, and their microvilli are comparable in length and density to those of the main retina. Type II cells bear stubby microvilli and various vesicles, but no photic vesicles. The ratio of type I to type II cells is about two to one in both accessory and main retinas. Certain electron-opaque cells scattered among corneal cells possess numerous photic vesicles and twisted microvilli that are confined to intercellular spaces. The cavity of the accessory eye, being separated from that of the main eye by two boundary layers, is filled with debris, such as granules, vesicles, and whorls.

Notes: Summary The long and slender spines of Diadema are highly flexible, although their skeleton consists mainly of CaCO3 and behaves optically like a single monocrystal of calcite. The flexibility is due to the shape of the spine skeleton as well as to the material properties of the echinoderm calcite. The spine skeletons are hollow beams consisting of radial wedges or septs. The shape of the septs shows a broad base situated at the periphery of the cross section, producing a high load-bearing capacity with minimum weight. Furthermore, material is concentrated at the base of the spine in such a way that the strain of the structure is kept constant along the axis. The septs are connected with one another by a few transverse bars positioned as closely as possible to the axis. The load-bearing parts of the septs are free. They have small diameters similar to flexible glass fibres. The stiff spines of other echinoids are also mainly built by radial wedges, but the spaces in between are closely filled with transverse bars. On the surface of stiff spines there are low grooves between the septs. The echinoid spines are covered with an epithelium which shows a basiepithelial nerve plexus. In the stiff spines this plexus forms cords which lie protected within the superficial grooves mentioned. In the flexible spines of Diadema the cords are deeply sunken in the spaces between the septs. In this manner the nerve cords are largely free from the tensile stresses to which the spine's surface is exposed. The flexible spines were used to determine the material properties of echinoderm calcite. Young's modulus was determined for fresh (live) spines, dry spines, and cleaned spine skeletons. Fresh spines show the highest elasticity, and their Young's modulus is significantly below the Young's modulus of the other test groups. The echinoderm calcite does not show the cleavage planes of mineral calcite, and probably this feature contributes to the high flexibility of echinoderm calcite.

Notes: Summary Heat stressed pigeons dissipate heat by panting and gular flutter which is associated with upper esophageal pulsation; these activities depend on evaporative cooling and convection from mucosal surfaces. The collar plexus, an unusual subcutaneous system of erectile veins, is the specialized vascular apparatus that seems to serve as the heat exchanger for gular flutter and upper esophageal pulsation. The collar plexus lies between the dermis and a deeper muscle sheet, extending from the head to the thoracic inlet in mature pigeons. The slightly filled plexus is inconspicuous, resembling an ordinary venous bed, and consists of thick-walled veins having small lumina, similar to arteries. When moderately-filled, the veins of the plexus distend and abruptly transform into “beaded” veins with contorted, sacculated expansions separated by constricted segments. During heat stress, engorgement of the plexus occurs rapidly by continual flow over arteriovenous anastomoses that empty arterial blood directly into the beaded veins. Constriction of veins draining the plexus impedes venous return to the jugular veins, thereby maintaining tumescence of the plexus. Disgorgement of the plexus also occurs abruptly. Intimate contact between the deep aspect of the engorged plexus and the trachea and upper esophagus provides for heat transfer from the plexus to the mucosal surfaces of these structures where evaporative cooling takes place. During esophageal pulsation the esophageal surface extends and augments the respiratory dead-space area used for evaporative cooling. Thus a possible advantage of cooling by upper esophageal pulsation is that, like gular flutter of the oropharynx, it may minimize the amount of air that must pass over gas exchange surfaces, thereby limiting the washout of CO2 and consequent acid-base disturbances that occur during panting in extreme heat stress. Ability to inflate the esophagus is of general occurrence among the pigeons and doves (Family Columbidae). The collar plexus is also widespread, having been found in representatives of five of the examined six main subdivisions of the Columbidae.

Notes: Summary 1. The development of taste hairs and tactile hairs of the fly Protophormia terraenovae is described using light microscope, scanning, and transmission electron microscope methods. 2. The development of taste hairs proceeds in the same way on tarsi, labella, and wings. First the dendritic outer segments of ciliary origin become visible above the hypodermal cell surface [2 days after pupariation (AP) at 19° C]; then the dendritic sheath starts growing out and finally the trichogen process follows. In a typical intermediate stage (‘stage C’) the distal sections of the dendrites float freely in the fluid surrounding the pharate adult. The more proximal sections are enclosed by the dendritic sheath around which the trichogen process is wrapped (4 days AP). The protruding dendrites disappear when the cuticle starts being deposited on the fully grown trichogen process, and the sheath vanishes later (9–10 days AP or 1 day before eclosion). The development is discussed with respect to the known structural organization of the adult hair. 3. In the tactile hairs the single dendrite which grows outwards is completely covered by the dendritic sheath and lies beside the trichogen process [stage C(m)]. 4. The taste and tactile hair development proceeds in the same way on legs isolated from the pupa after disc eversion in an artificial medium containing ecdysterone. 5. To check that both these patterns of development are widespread the development of taste and tactile hairs of the first instar cercus of the cricket Acheta domestica was studied with the light microscope: Both hair types pass through identical early stages.

Notes: Summary The larval endostyle consists of two ridges of secretory cells, which correspond to the two paired muciparous bands in the endostyles of the adult Branchiostoma, most tunicates, and the lamprey ammocoete. The peculiar shape of the larval endostyle is an effective adaption for food-trapping in the asymmetrical body of the larva. Contrary to general belief, the internal opening of the club-shaped gland is the site of the secretory release, while the exernal opening is an inlet for sea water. The water is mixed with the mucous substance, probably containing neutral glycoproteins, which is produced in the gland tube. This material is released through the internal pore dorsally in the buccal cavity at a position where it is carried with the endostylar secretion towards the intestine. The club-shaped gland is not part of the food-trapping mechanism, but it is apparently an important larval gland which produces substances which may act in the processing of the food or in some other way may direct larval life.

Notes: Summary Baker's yeast (Saccharomyces cerevisiae) suspended in the water that enters the incurrent canal system of the fresh-water sponge Ephydatia fluviatilis by way of the dermal pores is carried into the mesenchyme, where it is deposited against the surface of the flagellated chambers that generate the current. In the first phase of ingestion, as soon as the imported yeast cells have touched the choanocytes, the latter send extensive pseudopodia out into the mesenchymatic space to phagocytise the yeast cells there. Similar responses are elicited in the mesenchymatic cells during the second phase of ingestion and later in the pinacocytes of the excurrent canal system. All the cells of Ephydatia fluviatilis can phagocytise yeast cells. However, the yeast cells cannot be digested by the sponge cells and in the course of a few hours to 2 days they are expelled from the cells into the mesenchyme, whence they move transcytotically through the endopinacocyte lining into the excurrent canal system and eventually pass through the oscular tube to the exterior.

Notes: Summary The tissues of a fully grown echinoid skeleton are described using the primary spines of E. tribuloides as an example. Cidaroid spines are covered with an external, polycrystalline cortex, but as long as they are still growing they are covered with an epithelium. The mineral skeleton is embedded in the mesodermal stroma tissue which largely consists of fluid. Different types of mesodermal cells float within this fluid, but the sole characteristic stroma cells are the sclerocytes which are anchored to the calcite trabeculae by means of a cytoplasmic stalk. The latter spreads over the surface of the young trabeculae as a thin, continuous sheath, but on fully grown trabeculae it ramifies into numerous filiform processes (dp). The sclerocyte cell body is surrounded by a boundary layer which, however, is absent in the distal sheaths or filiform processes. The cytoplasm of the sclerocytes is electron-translucent and contains numerous free ribosomes. Sclerocytes which lie below the epithelium produce the cortex layer, and in the end the extracortical stroma as well as the epithelium vanish, and the cortex becomes external. Phagocytes within the stroma are at least as numerous as sclerocytes. They have a dense cytoplasm with long, straight pseudopodia protruding from it and running through the midst of the pore space. In normal conditions the pseudopodia do not touch the trabeculae. In a single instance, however, a phagocyte was demonstrated to etch a trabecula. Its etching face was crowded with clear vesicles which are not found elsewhere.

Notes: Summary Reabsorption of calcite is known to occur in echinoid endoskeletons. The structure of the operating cells is described using ‘Prouho's membrane’ as an example, which dissolves the skeleton of cidaroid spines within a thin section. After that the distal part of the spine is shed, and a new shaft grows out of the remaining stump. The calcoclast function is exercised by phagocytes which are also numerous in normal spine tissues. If the spine is highly damaged, however, the phagocytes assemble at a defined level and melt into a single syncytium, called Prouho's membrane. They fulfill three functions: (1) they show an extreme phagocytotic activity and ingest cells of the distal spine part, (2) they block off the surviving stump from the distal part shed later, (3) they etch through the calcite trabeculae in order to detach the distal spine part. The dissolution of the calcite starts with circular bulges, but in the end extremely thin etching lamellae run transversally through the trabeculae.

Notes: Summary The ommatidia of the compund eye of the krill, Meganyctiphanes norvegica, are composed of the following cell types: corneagenous cells, main cone cells, accessory cone cells, distal pigment cells, and retinula cells. The corneagenous cells secrete the cuticular lenses, below which the crystalline cones are present. The bipartite crystalline cone is formed within the main cone cells, whereas the accessory cone cells invest the distal part of the cone and proceed proximally in the retina to the basement membrane. Six distal pigment cells are arranged around each ommatidium, though shared by adjacent ommatidia. The seven retinula cells form the rhabdom, and penetrate the basement membrane as axons. The basement membrane is formed by the conjoined extended prolongations from the accessory cone cells and sheets from the basal pigment cells.

Notes: Summary Apodotrocha progenerans n.gen., n.sp. from tidal beaches or shallow waters on the east coast of the USA (Massachusetts) is a gonochoristic interstitial polychaete (length ca. 600 μm; six trunk segments), that lacks parapods, setae, and fleshy appendages, but has three characteristic caudal cirri. The habitus greatly resembles a larval stage of the Dorvilleidae, a family with which it also shares several anatomical features as revealed by ultrastructural investigations. Great similarities to the so-called archiannelids belonging to the Dinophilidae are also apparent, thus demonstrating the close phylogenetic relationship of the latter family to the Dorvilleidae.

Notes: Summary The ovary of the red abalone consists of a series of trabeculae or polygonal chambers that extend from the ovarian wall toward the wall of the digestive gland. The ovarian wall consists of smooth muscle cells and bundles of collagen fibrils, that extend into the trabeculae. Presynthetic, synthetic and early postsynthetic oocytes are surrounded by a single layer of follicle cells which bind these oocytes to the trabeculae. The follicle cells contain bundles of microfilaments. Mature oocytes lack a follicle cell layer and are found free in the chambers formed by the trabeculae. Each oocyte is surrounded by a vitelline layer, a chorion, and a thick jelly coat. Stages in the formation of these layers are described. It is suggested that prior to spawning the trabeculae detach from the wall of the digestive gland and retract toward the ovarian wall. Contractions of the ovarian wall may force oocytes out of the ovary into the seawater where fertilization occurs.

Notes: Summary The development of the aesthetascs of Neomysis integer (Malacostraca, Mysidacea) and Idotea baltica (Malacostraca, Isopoda) were investigated by electron microscope methods. Basically the aesthetascs of both species develop according to the same pattern. The newly formed sensillar shafts lie invaginated within the epidermal tissue. They are formed by numerous enveloping cells, which are arranged telescopically one by one. Each enveloping cell secretes a definite portion of the new shaft cuticle. The innermost enveloping cell extends furthest distally and deposits the cuticle of the future shaft tip. The outer enveloping cells produce the cuticle of the more proximal shaft portions. Whereas the morphogenesis of the aesthetascs of both species is uniform, the moulting processes are different. In the aesthetascs of Neomysis the morphological basis for a continuation of the sensitivity remains until ecdysis, as an intact dendritic connection between the sensory cells and the old shaft is maintained. In Idotea, the aesthetascs cease to function during the early moulting stages.

Notes: Summary A structural and ultrastructural investigation of epidermis in the esophageal region of Carinoma tremaphoros is correlated with analysis of burrowing locomotion. The pseudostratified epidermis contains multiciliated epidermal cells, gland cells and granule-containing basal or interstitial cells resting on a well-developed basement membrane. Both circular and longitudinal muscles are present within the epidermis, woven between the cells of this layer. These muscles are well-developed along the anterior region of the worm and, like the subepidermal muscles, are a variation of obliquely striated muscle without continuous Z-rods. Epidermal muscles originate as branches from the underlying mesodermal musculature and cross the basement membrane into the epidermis, confirming earlier observations. These muscles are unrelated to myoepithelial epidermal cells described in other metazoans. This condition is considered a secondary derivation consistent with the Gastraea-Enterocoel theory of bilateral metazoan evolution. Carinoma is a peristaltic burrower. Peristaltic waves are limited to the anterior region of the worm where the diameter of the rhynchocoel is maximal and the bilayered epidermal musculature is strongly developed. Following a consideration of burrowing mechanics in annelids, supernumerary epidermal muscles in Carinoma are interpreted as prerequisites to peristaltic burrowing effectiveness in a non-segmented coelomate.

Notes: Summary Light- and dark-adapted ocelli (LL and DD for 30 h) of seastars were studied by thin sectioning and freeze-fracture techniques for electron microscopy, and by histofluorescence. Lighting conditions affected the ultrastructure of the sensory microvilli, which became longer, more numerous, and more regularly arranged in darkness. A significant reduction in the density of intramembranous particles (IMPs) occurred in the sensory microvilli of LL specimens (6,600/µm2 in DD, 3,000/µm2 in LL) and, to a lesser extent, in the apical projections, but not in other membranous components including the cilia of the sensory cells. Additional observations on four other species revealed higher densities of IMPs in sensory microvilli than those in cilia. The fact that IMP densities of the LL sensory microvilli and the pinocytotic vesicles were nearly the same was considered to show the relationship of the two membranous structures. A specific fluorescence, indicative of the presence of retinal-based proteins, appeared only in the ocellar lumen of DD specimens, but practically none in LL ones. It was suggested that in the seastar ocelli the sensory microvilli are the primary photoreceptive sites and that they contain a rhodopsin-like substance. These conclusions support the view that asteroid photoreceptors are microvillar and not ciliary.

Notes: Summary Rhabdom formation was examined at the EM level in two members of the Chrysomelidae with different patterns of open rhabdoms (Leptinotarsa decemlineata — ponticulus pattern; Crioceris asparagi — insula pattern). Rhabdom morphogenesis, especially that of the central rhabdomere system of R7 and R8 is slightly different in both species and does not reveal which of the two patterns is primitive and which is derived. A close spatio-temporal correlation was found in L. decemlineata between the occurrence of a transitory modified cilium and the beginning of rhabdomere formation. The significance of this finding and its possible functional implications for the development of insect photoreceptor cells are discussed.

Notes: Summary The morphology of sternal glands and associated cuticular specializations are described for female polistine social wasps. Their distribution among 25 of the 28 genera of the subfamily is examined in light of what is known of the functions of these glands. Species in which queens found colonies independently of workers (four genera plus part of Ropalidia) have clusters of ducted gland cells on the sixth (terminal) gastral sternite. In all species examined the gland cells open into a tuft of long setae which probably functions as a reservoir/applicator brush. There is at least circumstantial evidence for all five genera that this gland produces an ant repellent substance that is smeared onto the nest petiole, where it serves as a defensive barrier against ants. The remaining genera (20 plus part of Ropalidia) consist of species in which queens are accompanied by a swarm of workers in the initiation of a new colony. In 12 of these genera females have a gland of ducted cells on sternite 5 (penultimate), associated with cuticular sculpturing of various types. Experimental or circumstantial evidence for several of these genera indicates that the product of this gland is used to lay an odor trail that guides the swarm from the parent nest to a new nest site. One genus has a similar gland on the sixth sternite, another has glands on both the fifth and the sixth, and the remaining six genera lack any evidence of sternal glands. The independent-founding species of Ropalidia have a sixth sternal gland associated with a tuft of setae, while the swarm-founding species have the tuft but lack the gland. Our interpretation of this is that the gland produces an ant repellent substance in the independent-founding species, but in the swarm-founding Ropalidia such a substance is of little value and so the gland has been lost.

Notes: Summary The flow of stained haemolymph was photographed in the wings of resting Pieris rapae, Pieris brassicae, and Gonepteryx rhamni under UV-radiation at definite intervals after abdominal application of fluorescent tetracycline. There is no circular route in the wing. All wing veins are supplied with stained haemolymph from their own bases without preference to single veins. In freely resting Pieris with intact wings, most veins are completely stained after 20 min. The staining pattern supports the existence of an oscillating haemolymph supply mechanism in the wing veins and shows that the cross vein and encircling sinus are not essential in the supply of the longitudinal veins. Inflow of stained haemolymph into the wing membrane begins about 1 h after application and is generally completed within 12 h in Pieris. The wing membrane is supplied with fluid by diffusion and — especially under low relative humidity — additionally by haemolymph substitution of evaporated water. This mechanism is associated with the disadvantages of water loss and probably salt withdrawal from the body. The puddling behaviour of butterflies might help in restoring these postulated deficits. It is hypothesized that haemolymph substitution of water evaporated from the wing membrane is a preadaptation for accumulation of defensive toxins and pheromones in the wing membranes, especially in diurnal and basking Lepidoptera. The veinal system of 5-day-old young summer specimens of Gonepteryx stains more intensely than that of 4–5-month-old specimens just before entering hibernation. The transition of stained haemolymph from vein to membrane is reduced in this species, probably as an adaptation for water retention during diapauses.

Notes: Summary The majority of large, bilaterally-symmetric animals possess two structurally distinct systems of internal fluid transport, the coelomic circulatory system and the blood vascular system (BVS). The coelomic circulatory system is generally situated laterally, lined by a continuous layer of mesodermally-derived cells and moves fluid with cilia or body wall muscles. The BVS occurs in extracellular matrix with the principal vessels situated dorsally and ventrally. The vessels are typically unlined by cells. Fluid is propelled by contraction of overlying muscle cells. Co-occurrence of two systems of internal fluid transport is explained by a segmentation hypothesis: Most large, triploblastic animals are segmented with at least two or three fluid-filled compartments separated by septal bulkheads. Because exchange surfaces (gas, nutrient) are regionally restricted, selective pressure favors a fluid transport system that bridges septal bulkheads. The BVS fulfills this requirement because it is situated in extracellular matrix that is non-cellular and continuous throughout organisms. A survey of animals indicates that all segmented taxa possess a BVS, except Sipuncula, where compensation sacs function as BVS analogues. Loss of the BVS in Hirudinea and other annelids is correlated with the disappearance of septa. Funicular vessels in Bryozoa are compared with BVS in other lophophorates. The fluid transport system of Nemertini and some platyhelminths is shown to conform to the definition of a coelomic circulatory system. This investigation supports Liwanow's proposition that the BVS evolved as the progressive modification of extracellular matrix in triploblastic animals. Evolution of coelomic circulatory systems is unresolved.

Notes: Summary Spermiogenesis and sperm cells of the meiobenthic priapulid Tubiluchus were described by means of the transmission electron microscope. The sperm cells are completely different from the male gametes of Priapulus, being elongated and thus indicating a different mode of sperm transfer. The anterior portion of the sperm head is characterised by a corkscrew configuration of nucleus and acrosome, both components being wrapped around each other. This kind of sperm cell has never been reported in other animal phyla.

Notes: Summary Freeze fracture preparations of the Branchiostoma epidermis revealed a number of specialisations of the plasma membrane. The highest number of intramembrane particles were found in the membrane of the microvilli, where they are predominantly localised in the P-face. In connection with the apical membrane an extracellular coat of complex branched filamentous structures (about 1.5 μm thick) can be demonstrated which was seen in carefully prepared transmission electron micrographs. In the area of the septate junction, the lateral plasma membranes are endowed with large numbers of variously sized membrane particles in the P-face which may form indistinct, short particle rows. The E-face is poor in particles. The freeze fracture image of this junction differs markedly from that of the mollusc-arthropod septate junction and bears similarities with the hemichordate and echinoderm septate junctions. Patches of particle aggregations suggest the presence of desmosomal contacts in the lateral membrane. No occluding or communicating junctions were found.

Notes: Summary Trichopsis pumilus has the same system of sound production asTrichopsis vittatus but with morphological differents. As distinguished fromTrichopsis vittatus muscels and tendons of the sound producing mechanism in femals ofTrichopsis pumilus are very reduced. Therefore probable femals ofTrichopsis pumilus are not able to produce sounds.

Notes: Summary Various types of surface microstructures and their distribution in the Giant Antarctic SlaterGlyptonotus antarcticus Eights, 1852, are described in detail. Although no attempt has been made to classify the different kinds of scales, leaf-like modifications, threads and feathery hairs, ideas concerning their origin and their function are presented. At least some of the microstructures described seem involved in discouraging foraminifera and larval stages of sessile organisms to settle upon the cuticle ofClyptonotus.

Notes: Summary The ultrastructural features of oogenesis were examined in the spionid polychaeteStreblospio benedicti. Paired ovaries are attached to the genital blood vessels extending into the coelomic space from the circumintestinal sinus. The genital blood vessel wall is composed of flattened, peritoneal cells, large follicle cells and developing oocytes. Vitellogenesis occurs while the oocytes are attached to the blood vessel wall. Two morphologically distinguishable types of yolk are synthesized. Type I is synthesized first by an autosynthetic process apparently involving pinocytosis and the conjoined efforts of the Golgi complex and rough endoplasmic reticulum. Type II yolk appears later through a heterosynthetic process involving the infolding of the oolemma and the sequestering of materials from the blood vessel lumen by endocytosis. During this process, blood pigment molecules appear to be incorporated into endocytotic pits, vesicles and eventually the forming yolk body. The significance of heterosynthetic yolk formation to the general reproductive strategies of polychaetous annelids is discussed.

Notes: Summary An ocellus of an anthomedusan, Nemopsis dofleini, is composed of sensory and pigment cells and underlain by a nerve plexus and a muscle sheet. A sensory cell is divided into three parts: an apical part from which a single cilium arises, a slender middle part with numerous microtubules and an enlarged basal part that contains an oval nucleus but does not send out an axon. The ocellar cup is occupied by variously remodelled ciliary sheaths that are covered by a few lysosomal projections from the pigment cells. Three modes of synaptic connections — centripetal, centrifugal and two-way — are found between sensory cells and either dendrites or somata of second order neurons. Synaptic vesicles in sensory cells are larger in number, smaller in size and more uniform in shape than those of second order neurons. The soma of a second order neuron lies below the surface layer of an ocellar cup and gives rise to a single cilium that lacks rootlets and the second centriole. The possibility of multimodal sensory perception in and around the ocellar region is discussed.

Notes: Summary The whip organs are situated proximally on the ventral side of most segments of the whip scorpion's whip. As the cuticular layer covering these organs is much thinner than the usual cuticle, the whip organs may be recognized easily under the light microscope as oval regions. The study of the ultrastructure reveals an epithelium characterized by apical and basal invaginations of the cell membrane with numerous mitochondria and prominent whorls of smooth endoplasmic reticulum. Thus, the whip organs possess the characteristics required for transepithelial transport processes. The possible function is discussed, based on experimental study.

Notes: Summary Structure and ultrastructure of the papillae in the mantle epithelium of the polyplacophoranAcanthochiton fascicularis are described. They consist to a major part of various secretory cells. Visual cells occur frequently in the papillae. Each of these organs form up to a few spines which have basally a cup of organic material. This connects the calcareous spine with the spine cell and often with a second cell which has distally one cilium. They are tactile receptors. Other spines are only for the defense and can be moved by muscles. They continue to grow basally in contrast to the tactile spines which are pushed off after some time and replaced by new ones formed in the papillae. The aesthetes and the mantle papillae are homologous organs.

Notes: Summary The mature male nephridia ofPolydora ligni andP. websteri (Polychaeta: Spionidae) are segmental organs composed of a ciliated nephrostome connected to a nephridial canal that crosses the intersegmental septum, expands into a large modified part extending dorsally through the coelom and subsequently narrows into a canal terminating in a dorsal nephridiopore. The nephridial canal is ciliated throughout and is composed of several cell types. Cells in the expanded region of the nephridia of both species contain large urn-shaped depressions filled with long microvilli. InP. ligni, one section of a nephridium contains cells packed with electron-dense granules that are not observed inP. websteri. The spermatophores ofPolydora ligni are composed of a central sperm mass surrounded by a layer of randomly oriented tubules that form a capsule around the sperm and taper into a long thin tail. These tubules are identical in dimensions to the microvilli present in parts of a nephridium and apparently are derived from these microvilli. The spermatophore capsule ofP. websteri is composed of similar tubules also presumed to originate from nephridial microvilli. The microvilli in nephridia of both species are surrounded with a glycocalyx that may function as an adhesive to hold the spermatophore capsule together. This glycocalyx may also function as a species specific message when encountered by a receptive female.

Notes: Summary The internal and external structure of the galeae of the adult red turnip beetle, Entomoscelis americana, was studied using SEM and TEM. The galea broadens from base to truncated tip and its sides are of thick, sculpted cuticle invested with pores and coarse spines. The tip is of thinner, flexible cuticle covered with 8–12 uniporous, blunt-tipped apical pegs and a single, aporous, sharply-pointed apical hair. The coarse spines are singly innervated probable mechanosensilla owing to the tubular body at the distal end of the dendrite. These sensilla likely act as tactile hairs monitoring galeal-effected movements of food particles into the functional mouth. The pores are associated with glands within the galea. The function of the presumed secretion is not known but may be to keep objects and dried saliva from sticking to the mouthparts. The apical pegs are innervated by five neurons, each producing a single dendrite. Four dendrites enter the single peg lumen and communicate with the terminal pore. The fifth differentiates into a tubular body that inserts into the peg base. These are typical insect contact chemosensilla that, because of their location, would taste incoming food. The apical hair has no pores but is innervated by two neurons, each extending a dendrite into the hair lumen in chemosensillar fashion. The sensory mode of this sensillum is unknown but is probably not mechanoor chemoreception. Many of its features, reminiscent of taste hairs, lead us to hypothesize that it represents a one-time chemosensillum recently modified to a new form and sensory mode. Because larval and adult E. americana share similar food plant requirements, we hypothesize that similarities will be seen in their mouthpart sensilla. Comparisons of the adults and larvae show the common features between their respective galeal taste hairs are only those of insect contact chemosensilla in general. However, the adult apical hair and the larval medial sensillum show striking specific structural similarities. We propose that these are true structural and functional homologues.

Notes: Summary The wall of the sinus venosus in an elasmobranchian species, Chimaera monstrosa L. is described. Endocardial cells contain numerous large vacuoles, as well as a number of membrane-bounded, moderately electron dense bodies (MDB). Myocardial cells lie closely packed into bundles surrounded by a basal lamina of about 20 nm thickness, and by large amounts of collagen fibres. These cells are connected by desmosomes of 1–2 µm length and with an intermembranous gap of 10–20 nm. Myocardial cells poor in myofibrils are intermingled with cells containing a well developed contractile material. Atrial specific granules are scarce. Vesiculated nerve processes occur at a distance of about 20 nm from the myocardial sarcolemma. Myocardial cells of the sino-atrial junction appear ultrastructurally similar to those located elsewhere in the sinus venosus. Epicardial cells contain large vacuoles, and have fibrecoated protrusions extending into the pericardial space. The possibility of pacemaker activity in the elasmobranchian sinus venosus is discussed.

Notes: Summary The nature and homologues of the appendages of the anterior end of the polychaete families Sabellidae and Serpulidae have long been discussed. The main purpose of the present investigation, in which seven sabellid and eight serpulid species are studied, is to contribute towards the solution of these problems. At the same time, however, the present study, within its limited range, aims to enlarge our knowledge of the anatomy of the polychaetes in general. Such a knowledge, it is argued, is a prerequisite for further consideration of the phylogeny of the Polychaeta. As shown in many earlier papers, the architecture of the cephalic nervous system and the innervation of the organs and appendages of the anterior end of polychaetes constitute reliable instruments for elucidating the morphological significance of these structures. In the present paper, consequently, extra consideration is given to descriptions of the central nervous system of the sabellids and serpulids studied. The integumental depression found in front of and below the brain of all the sabellids and serpulids here studied is described by the term “dorsal pit”. It is concluded that the dorsal pit within each family in all probability represents a homologous structure, but it is in no way proven that the dorsal pit of the sabellids is equivalent to that of the serpulids. Some earlier literature maintains that paired antennae [antennes de première paire in Binard and Jennerś (1928) terminology] are found in some sabellids and serpulids. In the present paper it is maintained that these structures must instead be interpreted as nuchal organs. Such organs are found in all the sabellid and serpulid species here studied. The Pruvot-Meyer theory which claims that the joint pore of the thoracic nephridia of the “serpulimorphic” families is equivalent to the nuchal organ of other polychaetes is shown to be without foundation, and it is consequently rejected. The histology, vascularization, and innervation of the branchial crown and the appendages of the dorsal lip of the mouth of the species investigated are described. It is concluded that the branchial crown and some (but not all) appendages of the dorsal lip are equivalent to the palps (when present) of the “spiomorphic”, the “drilomorphic”, and the “errant” polychaetes. The appendages of the dorsal lip of the mouth, in most faunistic literature called palps, are found to represent structures of three different kinds and origins: (a) branchial radioli which have become separated from the crown and have fused with the lip, (b) branchial pinnulae which have undergone a similar process of dislocation, and (c) new formations from the walls of the mouth cavity. It is proposed that in comparative-anatomical works these appendages should be called (a) lip-associated radioli, (b) lip-associated pinnulae, and (c) outgrowths of the dorsal lip respectively. As a joint and anatomically neutral term to be used in faunas and descriptions of the outer morphology, the expression “appendages of the dorsal lip” or, more briefly, “(dorsal) lip processes” is proposed. The interrelationships of the Sabellariidae, the Sabellidae, and the Serpulidae are discussed, as is the taxonomic subdivision of the last two families. In agreement with some earlier authors although contrary to others it is thereby maintained that: 1) the suborder Serpulimorpha Hatschek (1893) (inclucing sabellariids, sabellids, and serpulids) does not constitute a natural systematic unit; 2) the sabellids and serpulids, although markedly different in many respects (thoracic membrane, operculum, branchial skeleton), are probably closely related to each other. Earlier arguments supporting this view are corroborated by data on the dorsal lip processes and the architecture of the brain of the two families; 3) Rioja's (1923) division (based on setal structures) of the Sabellidae into the three subfamilies Sabellinae, Fabriciinae, and Myxicolinae is supported by the anatomical data emphasized in the present paper; and 4) within the Serpulidae the genera Apomatus and Protula should be referred to the subfamily Filograninae [as proposed by Rioja (1923), followed, among others, by Fauvel (1927), and Hartmann-Schröder (1971)] and not to the Serpulinae, [as maintained by Hartman (1959) and Fauchald (1977)]. Again, the view presented by the present author is founded on anatomical data (the morphological value of the dorsal lip processes of the genera in question).

Notes: Summary The amphipod species Haploops tubicola has an unusual compound eye that is divided into three separate parts, each with one common cuticular lens. The dorso-frontal eyepair has, in addition to the lens, a so-called vitreous body, which is constructed like a dioptric lens and is inserted in the ray-path. The ‘vitreous body’ is actually — and for which evidence is presented — a secretory product formed in the intercellular spaces of the organ of Bellonci. Histochemical analysis has shown that the secretion is strongly PAS-positive and lacks glycogen.

Notes: Summary Linear viscoelastic properties of laboratory handsheets have been investigated from the two dimensional aspect. According to the linear theory of viscoelasticity, the behavior of transverse isotropic materials such as handsheets subjected to plane stresses is fully described by the two in-plane relaxation functions G11 (t) and G12 (t). In the present paper, some viscoelastic characteristic functions describing responses to in-plane deformation histories are derived from G11 (t) and G12 (t) determined by strip biaxial stress relaxation testing. The predicted uniaxial relaxation function curve was in good agreement with the experimental one, and the viscoelastic Poisson's ratios in uniaxial stress relaxation and in uniaxial constant strain rate extension were decrease functions of time. Effects of beating on the areal dilatation and shear relaxation functions are discussed by introducing the classical concept of relaxation spectrum.

Notes: Summary This electron microscopy study is concerned with the dormant cambial cells in compression wood of Picea abies (L.) Karst. The cambial zone comprised 4–8 rows of fusiform cells. Each radial file contained the group known as Sanio's four, namely an initial, a mother, and two daughter cells. Groups of three, resulting from a failure of a mother or a daughter cell to divide, were also present. Undifferentiated xylem tissue cells occurred singly, in pairs, or in groups of four. These cells and the last-formed tracheids were often enclosed by a common primary wall. The fusiform cells had a large, elongated nucleus, numerous small vacuoles, and a frequently infolded plasma membrane. Golgi apparatus and endoplasmic reticulum were rare, while plastids, amyloplasts, and lipid droplets were common. Cambial ray cells contained much lipid material. The tissues were similar to cambial tissues in normal wood of conifers. The present results can only be interpreted in terms of the single layer of initials and sequence of cell divisions established by Sanio. The initial can be located by several criteria in dormant and active cambial regions in conifers. It could be shown that the existence of the group of Sanio's four is better documented in the literature than has so far been recognized. The occurrence of a variable number of primary cell walls is discussed with reference to the concentration of lignin in the middle lamella of mature xylem.

Notes: Summary The technology and chemistry of recent advances in alkaline pulping are reviewed from the standpoint of the authors' work over the past few years. Topics reviewed include soda-amine [particularly soda-ethylenediamine (EDA)], soda-anthraquinone (AQ), kraft-AQ, and soda-AQ/EDA pulping and their effects on pulp strength properties and bleachability. There is evidence to support the concept that the rates of all alkaline delignification reactions, including kraft, are controlled by a reductive step which transfers electrons to the degrading lignin.

Notes: Summary A lignin-carbohydrate material from black spruce (Picea mariana) was treated with a hemicellulase mixture. The carbohydrates in the remaining material were studied by the following methods. a) Treatment with 0.1 M NaOH in the presence of sodium borohydride followed by selective hydrolysis of the furanosidic bonds, b) Smith degradation (periodate oxidation followed by mild acid hydrolysis). The results obtained indicate that lignin is bound to all types of sugar units in the hemicelluloses. For arabino-4-O-methylglucuronoxylan, linkages to the side-chain units seem to dominate. The links to the 4-O-methylglucuronic acid units are ester bonds, probably benzyl ester bonds. Those to the other sugar units in the hemicelluloses are ether bonds, probably benzyl ether bonds. The results suggest, furthermore, that fractions of cellulose are linked to lignin.

Notes: Summary NPA, applied in a 2–3 cm band around the middle protion of 2- or 3-year-old internodes of three vertically-oriented six-year-old Sugi trees (Cryptomeria japonica D. Don), brought about abnormal thickening all over the upper segment from the NPA treatment. Xylem tissues above and below the treatment, as well as at the treated area itself, was examined by ordinary light microscopy and by scanning electron microscopy. The results obtained seemed to indicate that the tissue formed after treatment in the upper segment of the stem was true compression wood. In the lower segment of the stem, no abnormal tissue but a small amount of latewood-like tissue was produced after treatment. Referring to the previous studies in which morphactin, another IAA transport inhibitor, has induced compression wood, we consider it likely that compression wood formation must be induced by high concentrations of endogenous IAA, which could be brought about by blockage created not only by NPA and morphactins, but also by IAA transport inhibitors in general.

Notes: Summary Tangential latewood sections (60 μm) of Scots pine sapwood were differently treated with chlorite. The subsequently incubated two strains of Bacillus polymyxa caused a weight loss up to about 25%, including a loss of lignin of about 42%. UV-microspectrophotometry of 1 μm-cross-sections prepared from the cultured woody tissues demonstrated that bacteria caused neither quantitative nor qualitative changes of the remaining lignin. The lignin, which was dissociated from the pretreated woody cell wall by bacteria, could not be respired, suggesting that the lignin is a ‘ballast’ to these bacteria that inhibits the dissimilation of the carbohydrates in the wood.

Notes: Summary An acoustic resonance technique has been evaluated as a means of detecting deterioration in wood poles. The basis of the technique is that degradation of the pole by rot or other agency will lead to an increase in the damping of longitudinal acoustic waves, which can subsequently be detected by an examination of the acoustic resonance characteristics of the pole. The technique was assessed in a series of field trials conducted on in-situ poles, which were subsequently removed and dissected. The results of the acoustic testing compared favourably with the gradings of the poles following dissection.

Notes: Summary Historically, adhesive development has been a propelling force in the evolution of the forest product industry. The 1973 energy crisis has caused the wood industry to focus its attention on the necessity of adhesive self-sufficiency. Research in the use of bark, pulp waste liquor and foliage for adhesive application is rapidly spreading. In addition, many new adhesives have been proposed by the chemical industry as alternatives for wood bonding. Recently developed physiochemical analytical methods have been successfully applied to this adhesive research area and to durability evaluation. However, there are still enormous difficulties in developing a durable natural product adhesive of low variability as well as a unified international interpretation of bond durability. Phenolic resins have weathered the energy crisis and are gaining importance in the industry. Some examples of recent contributions from phenolic-resin research to panel board and lumber end-joint developments will be discussed in detail.

Notes: Summary The fine structure of inactive eastern white spruce phellogen (Pg) and phelloderm is briefly described. Phellogen cells resemble dormant cambium but contain larger tannin vacuoles. Phelloderm cells contain even more tannin and have much thicker primary walls. Three types of phellem are described: crystalliferous phellem (CP), thin-walled phellem (TnP), and thick-walled phellem (TkP). All three occur in spruce, but only the latter two in balsam fir and eastern hemlock. The TnP cells have thin shared common walls overlain by suberinic and wax extractive layers. True pits are lacking, but plugged plasmodesmatal canals sealed over by the wax extractive layers cross the suberinic layers. Spruce CP and fir and hemlock TnP cells have adaxially-thickened suberinic and wax extractive layers when adjacent to TkP or inactive Pg. The suberin lamellae are much thickened in these suberinic layers, at least in spruce. Spruce CP has a thick wax extractive layer which also sheaths the crystals. The TkP cells of all three species have thick polylamellate abaxial cellin walls perforated by simple pits. The lamellae differ both in structure and composition. Polylamellate wall construction is discussed and a model proposed. The TkP cells have both suberinic and wax extractive layers in fir and hemlock, but only wax extractive layers in spruce. These cells are therefore true phellem cells, not phelloids.

Notes: Summary Deflections of wooden beams loaded repeatedly for seven or two days in every 14 were compared with those of beams under constant load over a period of six months in a constant environment. Four load levels were applied to beams of three species. Loads ranged from 17 to 67 per cent of short-time failing load estimated from matched specimens. The deflections under intermittent loads were lower than the creep deflections under constant load and, with the exception of material under high stress, applicability of Boltzmann's principle of superposition of deformations was confirmed. Non-linearity at high stresses is linked with other signs of weakening after application of loads in excess of about 50 per cent of short-time ultimate.

Notes: Summary A computerised wood densitometer system using X-rays is described. The technique uses 5 mm increment core samples, machined to 2 mm thickness in the axial direction of the fibre, and an isotopic radiation source (Fe 55). Direct measurement of the intensity of radiation passing through the sample enables wood density variations to be recorded automatically and stored on disc file for subsequent analyses with an interactive computer program.

Notes: Summary An equation is derived to describe transverse nonisothermal moisture movement in wood, based upon a gradient of chemical potential. When compared with a previously derived equation based upon a gradient of activated moisture molecules, this new equation predicts an accentuated effect of the thermal gradient relative to the moisture gradient at high wood moisture contents and a decreased effect at low moisture contents. The two equations yield identical results at a moisture content in equilibrium with a relative humidity of approximately 53 percent.

Notes: Summary The hypochlorous acid formed intermediately during the bleaching of an oxygen-prebleached kraft pulp with pure chlorine dioxide (a D0-stage) was captured as N-chlorosulfamic acid by addition of sulfamic acid to the bleaching liquor. The amount of hypochlorous acid captured corresponded to about 50 mol% of the consumed chlorine dioxide. The amount of chlorite formed (20 to 30 mol%) was less than the amount of hypochlorous acid captured. The excess of hypochlorous acid over chlorite suggests that chlorine dioxide is reduced initially not only by a one-electron mechanism to chlorite but also by a two-electron mechanism to monochlorine monoxide, which is then reduced by lignin or by chlorine dioxide to hypochlorous acid. The routes for the further reactions of chlorite, monochlorine monoxide and hypochlorous acid are discussed.

Notes: Summary Ultra-high pressure water jets, operating at 48 300 kPa through a ring-type No. 6 nozzle with 15° fan and 1.57 mm diameter opening, were used in practical trials for debarking several hardwood species. Eucalyptus paniculata, E. agglomerata, E. acmenioides, E. pilularis and Syncarpia glomulifera were tested, as they are known to be difficult to debark. The effects of these jets on the configuration of the detached bark, were also assessed. Except for E. pilularis, all species were effectively debarked, and a classification was made of the relative difficulty with which various barks were removed. In E. pilularis the bark adhered strongly to the timber, the surface of which was extensively damaged by the water jets. The high pressure water often broke and shattered the bark, which sometimes underwent pronounced defibration. In particular, the bark of E. acmenioides and E. paniculata was broken down into a material, which should be readily utilisable without further processing. Finally, these trials have shown that the design of a small-size hydraulic debarker is feasible and should eventually be a commercially viable proposition.

Notes: Summary The purpose of this study was to assess the relationship of oven-dry density, initial moisture content, vascular bundles and shrinkage to stem height and diameter of Cocos nucifera L. High correlations were obtained between initial moisture content and stem height, initial moisture content and oven-dry density, oven-dry density and stem height, vascular bundles per cm2 and stem height, vascular bundles and oven-dry density for cross-sections and shrinkage and vascular bundles per cm2. The high correlations between vascular bundles per cm2 and oven-dry density on the one hand and to shrinkage on the other can be used for visual grading of coconut timber.

Notes: Summary In the present paper a hydrothermolysis apparatus is described. The reaction vessel is of the percolator type with a volume of 560 cm3 and permits the hydrolysis of biomass materials up to 100 g. The optimum degradation conditions of pure cellulose (filter paper) were determined in dependence on temperature, flow rate of the eluting water and influence of stirring on the reaction mixture. Up to 52% glucose can be obtained by hydrolysing cellulose with pure water at 265°C at a flow rate of 12 cm3/min. Biomass materials such as poplar wood and wheat straw were hydrolysed in two stages, using temperatures of about 200°C for the easily hydrolysable polysaccharides and about 260°C for the polysaccharides, which are more difficult to hydrolyse. In the first stage on an average 45% of the initial amount is converted into soluble products, whereas in the second stage this value amounts to 48%.

Notes: Summary The use of ammonium sulfide in aqueous ethanol and methanol was investigated for pulping of wood. Hemlock chips required 21% ammonium sulfide (equivalent to 19% Na2O) at 180°C to become delignified to the kappa range 35–50. The yields exceeded those of conventional kraft pulps by 14% on dry wood basis. Over 75% of the original glucomannan was recovered in the pulp as the consequence of end group stabilization by ammonium sulfide. The intrinsic viscosity of the pulps, measured in cadoxen was 10.65 dl/g — approximately double the value for softwood kraft pulps. The pulps were readily bleached and possessed higher tensile and burst strengths but lower tear strengths than kraft pulps. Ammonium sulfide pulps from cottonwood were likewise obtained in high yields and with adequate strength properties.

Notes: Summary Changes in the submicroscopic porosity in southern pine latewood resulting from pyrolysis at temperatures through 600°C were measured using small-angle X-ray scattering. Two types of scattering curves were observed: the first was obtained for wood and for less intense heat treatment; and the second, for samples heated above 300°C. This change was found to be associated with the thermal degradation of crystalline cellulose in the sample. Specific surfaces and the average dimensions of macropores and micropores were calculated from the second type of scattering curve. The specific surface was found to increase from 1.2 to 2.3 m2/gm as the temperature and heating time increased. The average dimensions of the macropores calculated from the scattering curves was about 15 nm. The first effect of heating sufficiently to decompose the crystalline cellulose was found to be the production of micropores with average diameters of about 0.7 nm. Micropore volume increased from 0.06 cm3/gm for the lower heating temperatures to about 0.13 cm3/gm for samples heated to 600°C. The average micropore dimension increased as the temperature was raised and the samples were heated for longer times.

Notes: Summary In a typical sawmill, about 12% of the wood which is cut is reduced to sawdust. Further material is lost during subsequent planing. A substantial part of this large loss of a costly natural resource can be saved by the use of thin, stable sawblades, but only if proper saw tensioning conditions are developed. The thickness of a stable sawblade can be minimized through optimal tensioning, an increasingly urgent objective because of sharply rising raw material costs. A theoretical model is presented which accurately describes the development of residual stresses in a roll tensioned circular sawblade and the resulting changes in saw critical speed. This model is essential for the reliable prediction of optimal tensioning conditions for any given saw operating state, and for the development of automated control of the tensioning process. An example is presented of an optimally tensioned circular sawblade for which a 40% thickness reduction is achieved compared with an equivalent untensioned sawblade with the same critical speed.

Notes: Summary The paired buccal ganglia ofHelix pomatia were investigated by light microscopical methods. Number and location of the buccal nerves show a certain variability. The caudal surface of the buccal ganglia was standardized, and the location of single neurones and groups of neurones was entered in the standard sketch. Normally there were found four giant neurones (B1–B4, diam. 120–170 μrn) in each ganglion, three of them in the lateral lobe and one (B4) in the medial lobe. The run of the nerve cell processes of B1–B4 was traced with the aid of retrograde filling with CoCl2 or in series of toluidine blue stained semithin sections. The run of the axons of B1–B4 proved to be constant. The nerve cell processes of each B2 project into both ipsi- and contralateral first salivary gland nerves. Obviously the salivary glands of each side are innervated by both right and left B2. Besides the four giant neurones two characteristic nerve cell groups (diameter of the perikarya 20–30 μrn) could be localized. The staining properties (paraldehyde fuchsin-positive) suggest, that one cell group contains peptidergic neurosecretory material. The second cell group contains catecholamines as it was shown with the aid of formaldehyde induced fluorescence. The results are discussed with findings of different authors at different slugs and snails, to point out homologies in the cellular organization of the buccal ganglia.

Notes: Summary The ultrastructure of the auricles, the ostia, and the ventricle of L. asellus and T. marmorea is described. The heart wall consists of an epicardium, a basement membrane, and an inner loose myocardium. The epicardial cells of the auricle are podocytes. The exposed cell body and the branched processes show pedicles. Ventricular epicardium is flat and simple. The slender, unbranched, mononucleated muscle fibres have a peripheral nucleus located midway along the fibre. Mitochondria are peripherally located, leaving the center to longitudinally running thick and thin myofilaments. Dense bodies and attachment plaques make up the Z-material. Sarcomeres and myofibrils are absent, as are transverse tubules and intercalated disks. The sarcoplasmic reticulum consists of peripheral tubules and subsarcolemmal cisternae, some of which radiate, branch, and run between myofilaments. Couplings are lacking. Ventricular fibres in T. marmorea show nexuses and desmosomes; in L. asellus only nexuses. The muscular ostia are tubular, and muscle fibres resemble those of the ventricle; nexuses are detected in T. marmorea and desmosomes in L. asellus. The only nervous elements observed are some nerve processes, structurally similar to those of other molluscs.

Notes: Summary The neuropile regions in the supraesophageal ganglion ofLocusta migratoria were revealed by Bodian staining of frontal and parasagittal sections. A combined recording and staining technique (CoS method, Rehbein et al., 1974) was used to identify physiologically five different types of auditory ventral cord neurons and mark the course of their axons and the positions of the terminal arborizations. The boundaries of the projection regions are described; they include the various multimodal neuropile regions in the ventrolateral protocerebrum. Previously demonstrated instances of convergence with neurons of other sensory systems, and others likely to exist, are considered with respect to their possible significance in neuronal processing within the auditory system.

Notes: Summary The branchial vasculature of the smooth toadfish,Torquiginer glaber, was studied by light microscopic examination of Microfil vascular casts, and scanning electron microscopy of critical point dried tissue and vascular corrosion casts. The anatomy of the respiratory vascular bed was similar to that described for other teleosts. An extensive non-respiratory vascular bed was also present in the gills. In each filament this comprised a series of capillaries arising mainly from the efferent side of the gill circulation (efferent filament artery, efferent lamellar arterioles, branches of the efferent branchial artery), but also from the afferent side (afferent filament artery, afferent lamellar arterioles, lamellar blood channels). The capillaries eventually connected to a system of broadly interconnected sinuses in the filament termed the central canal and the afferent and efferent companion vessels. The sinuses connected with a large subepithelial sinus and a pair of venolymphatic vessels in the gill arch. Connections between the subepithelial sinus of the arch and the anterior venous system were demonstrated. It is suggested that the non-respiratory capillaries serve a nutritive function, while the filament sinuses provide a combined venolymphatic drainage for the filament.

Notes: Summary The hyomandibula is an important element of the head and has been influenced in its structural features by different functions. It is roughly T-shaped with vertical and horizontal ridges. In fish, such asMacropodus opercularis, the deep curve at the antero-dorsal end of this ridge may be correlated with the concentrated force applied by the adductor mandibulae muscles. InMacropodus opercularis, the hyomandibula is shorter and broader than that ofAnabas testudineus andCtenopoma acutirostre. In the latter two genera, almost the entire anterior surface of the vertical ridge is uniformly curved, which may be explained by the distributive force applied by the adductor muscles perpendicularly. InMacropodus, the hyomandibulo-interhyal articulation is not straight along the axis of the interhyal as inCtenopoma, but the interhyal makes an angle of 45

Notes: Summary The types of cell death in the midgut epithelium of the worker honey bee during the larva-to-pupa transformation were analyzed by light and electron microscopes. The metamorphosis begins with an increase in the number of autophagic vacuoles in larval epithelial cells and terminates with lytic destruction of the whole intestinal epithelium. Apoptosis seems to be independent of cell age, but important in fashioning of the new organ. Even in the cells in the regenerative nests of the larval epithelium, from which the pupal epithelium develops, apoptotic death occurs. Single apoptotic cells are eliminated gradually from the primary multilayer tissue until the monolayer pupal epithelium is formed. Some of the apoptotic cells are endocytosed by sister epithelial cells.

Notes: Summary 1. Exocrine glands found in the anterior hindgut of the millipedesPolydesmus angustus andGlomeris marginata should be termed pyloric glands. 2. The pyloric glands ofPolydesmus angustus are appropriately differentiated hindgut epithelial cells. Every single cell shows secretory activity. 3. InGlomeris marginata the pyloric glands are composed of three types of cells: secretory cells, transitional cells, and canal cells. 4. The size and form of the pyloric glands are related to the length of the hindgut. 5. The secrete of the pyloric glands is dispersed on the hindgut intima as a thin film. 6. This secretion layer seems to influence the permeability of the hindgut and play an essential role in the reabsorption of water and other important compounds.

Notes: Summary Adhesive organs of 17 gastrotrich species of the order Macrodasyida and 2 species of the order Chaetonotida (Chaetonotida-Paucitubulatina) can be seen by transmission electron microscopy to comprise two gland cell types. These cells are morphologically similar to viscid and releasing glands of the Turbellaria and so are identified by these same names; the adhesive system in these gastrotrichs is therefore called a duo-gland system considered at least functionally comparable to the duo-gland organs of turbellarians. The two gland cell types project their necks through tubiform extensions of the animal's cuticle. Some adhesive tubules have only one of each gland type; others, even in the same species, may have two viscid and one releasing glands; and compound organs such as posterior footlike appendages may have three and four viscid glands and one releasing gland per tubule. Gland cells in some species have fibers, evidently cytoskeletal in function. The adhesive tubules are quite similar in all of these species and provide few characters for determining within-group relationships of the gastrotrichs. The duo-gland system of the Gastrotricha is probably not homologous with that of the Turbellaria.

Notes: Summary The water-conducting system ofEphydatia fluviatilis includes sluice-like structures at the critical sites, some of them at the surface of the sponge and some inside it. These are dermal pores, pores in the walls of the inhalant and exhalant canals, and the osculum. The characteristic common to all of these openings is the porocyte, a disk-shaped cell with an aperture in the middle, so that it has an annular appearance. The shape and fine structure of the cells with pores, as well as their position in the pinacocyte epithelium and the impermanence of at least the dermal pores, indicate that these cells are regular pinacocytes serving a special function. The porocytes in the walls of the exhalant canals always appear in association with a flagellated chamber, with which they are connected by way of two or three modified choanocytes that form a double cone. The osculum at the distal end of the egestion passage, is the product of two porocytes, derived from the exopinacocyte and the endopinacocyte epithelia and having congruent apertures.

Notes: Summary The morphology and ultrastructure of the ovarioles ofRaphidia flavipes are described. The ovary ofRaphidia shows all the structural elements by which the telotrophic ovarioles of Megaloptera can be distinguished easily from those of polyphage Coleoptera or Hemiptera. This supports the view of sister-group relationship between the Raphididae and the Sialidae.

Notes: Summary On the antennulae ofLeptestheria dahalacensis (Conchostraca) nearly 600 sensory setae of one type are found. They are gathered in groups of 25–30. The single sensory seta is divided into two parts by the basal bead which is easily visible in the light microscope. The basal bead is the socket of the seta, whose wall is mainly built up by the epicuticle. The terminal pellet closes the tip of the seta. The basal bead is derived from the innermost layer of the epicuticle. 4–10 dendrites each with one receptorcilium innervate the receptor. The receptorcilia stretch through the interior part of the receptor and the basal bead into the exterior part, where they branch. They enter the terminal pellet in a porus, which seems to be a moulting porus. The interior part of the receptor is surrounded by 5 sheath cells. During the premoult it becomes obvious, that the socket of the seta is built by the sheath cell 5, the basal bead by the sheath cell 4 and the shaft by the sheath cell 3. For this the sheath cell 3 is divided into two parts. Between this two parts the newly formed cuticle is invaginated. The sheath cell 2 formes the tip and the sheath cell 1 the cuticular sheath of the new bristle.

Notes: Summary A comparative ultrastructural study of trunk segments of a variety of small polychaetes (body diameter less than 250 μrn) was undertaken to determine whether small body size is correlated with deviations from the typical annelid pattern of coelomic organization. Peritoneum is never found covering oblique or parapodial muscles traversing the body cavity. Aside from this, two major patterns of body cavity organization are seen: 1. spacious body cavity with varying extent of peritoneal lining (complete, partial, absent) and 2. the body tending toward the acoelomate condition, as a result of the expansion of lining cells or the lack of initial cavity formation. The significance of these anatomical variations is discussed with respect to functional and phylogenetic considerations.

Notes: Summary Woodlice are unique among the arthropods in moulting in two halves. The intramoult is 1.8 days inOniscus asellus and results from the two halves being out of synchrony throughout the cycle. In the integument, the initiation of a new moult cycle is heralded by epidermal cell vacuolation; a little later, the subepidermal tissue proliferates and, for a brief time, macrophages appear. The cuticle layers are produced in order, starting with epicuticular structures such as tricorns and plaques, followed by the biphasic epicuticle, the lamellate pre-ecdysial cuticle and, after ecdysis, the lamellate postecdysial cuticle. Epicuticle is formed in a continuous sheet along the distal epidermal membrane and postecdysial cuticle from fibres formed within the cell body — both features not reported for other arthropods. Immediately prior to ecdysis the epicuticle and pre-ecdysial cuticle are highly corrugated and the epidermis very constricted as the width of the ecdysing gap is increased by the new cuticle components withdrawing slightly beneath the old cuticle. At this time the space between the two cuticles appears devoid of the fluid that once occupied it, although the ecdysial membrane is still apparent. After ecdysis the appearance of the epicuticle changes due to chemical events which make it relatively impermeable. The pre-ecdysial cuticle also changes in appearance at this time due to the physical stress of expansion. Large cuticle precursor vesicles, similar to those of other Crustacea, are particularly associated with postecdysial cuticle production. In addition there are numerous small vesicles associated with pre-ecdysial cuticle formation. The epidermal vacuoles disappear as postecdysial cuticle is produced so that, when it is complete, the epidermis is again a narrow cell layer. Apolysis occurs straight after this and shortly afterwards the cycle recommences. Unlike other arthropods woodlice do not expand to break free of the old cuticle instead they walk free of either half and then expand. Experimental evidence is given which suggests that woodlice do not take in water to achieve this expansion but rather, they appear to employ internal hydrostatic pressure. Using published data from woodlice endocrinological studies and the present work a possible method of hormonal control of the biphasic moult is suggested.

Notes: Summary The structure of the sound-transmitting apparatus in primitive snakes (Scolecophidia, Henophidia) is reviewed and compared with that of advanced snakes (Caenophidia) and of some fossorial lizards. Assuming a constant course of the chorda tympani, the ophidian stylohyal can be homologized with the intercalary cartilage of lizards while the cartilaginous distal portion of the ophidian stapes represents the internal process. The cladistic significance of the stapes-quadrate-articulation in the Henophidia and Caenophidia is discussed. The Booidea and the Caenophidia show a shift of the stapes-quadrate-articulation which is correlated with changes in the suspensorium as an adaptation to relatively larger prey. However, convergence cannot be ruled out. Dibamus is shown to be the only lizard known so far which approaches the ophidian middle ear structure. Convergence has to be assumed since there is no sign of a stylohyal in Dibamus and since the course of the ramus communicans externus n. facialis cum glossopharyngeo supports the hypothesis that snakes are to be derived from a pre-lacertilian stage of lepidosaurian evolution.

Notes: Summary The antennal circulatory organs of Melolontha are described for the first time. They consist of small sac-like ampullae located near the base of each antenna and connected to a long non-muscular antennal blood vessel. Small branches of this vessel extend into each lamella of the antennal club and open out distally. The membranous wall of the ampulla provides no contractile structures. An outer adjacent compressor muscle is responsible for the pumping movements of the ampulla and antagonist to it is an obviously elastic connective tissue band. The position of this elastic band causes the uncontracted muscle to be pulled away from the ampulla. As a consequence blood can enter the dilated ampulla through a valvular ostium. The functional type of the antennal circulatory organs in Melolontha is compared to that found in other insects and their histologic structure is interpreted in relation to mechanical and hemodynamical aspects. Furthermore the possible function of the antennal hearts in connection with the spreading of its lamellate antennal club is discussed.

Notes: Abstract The posterior colon of worker-caste termites accommdates an abundant, heterogeneous population of procaryotic organisms which are retained by attachment to prominent cuticular spines elaborated from the gut wall. The spines extend to nearly one half the diameter of the lumen and are each supported by a specialized root cell in which bundles of parallel microtubules traverse the cytoplasm from the apical to the basal surfaces. Additional epithelial cells are present which show infoldings of the apical plasma membrane and are overlain by cuticle containing deep, vase-shaped pits opening to the gut lumen. It is proposed that the root cells are designed to resist shearing forces transmitted to the base of each spine during contractions of the gut. The cuticular pits may represent sites of permeability to the end products of microbial metabolism.

Notes: Summary The one-point joint linking the antennula with the carapace in Panulirus argus is described. A strand organ is activated when the antennula is moved in the vertical plane. Its structure, function, and regeneration after severance were investigated. The implications of this system are discussed, starting from the findings that the strand organ counteracts the statocyst (located in the antennula) in such a way that gravity reactions occur only if the body changes its position with respect to gravity.

Notes: Summary Vascular corrosion casts of the brachial circulation in Octopus were observed under the scanning electron microscope. The angioarchitechture, particularly of the smaller vessels, was revealed with a clarity not previously attained. The casts are very similar in appearance with those obtained from vertebrate tissues, emphasizing the convergent development of the closed system in the two groups, and form a useful basis for further study of vascular structure and function in Octopus.

Notes: Summary Kraft and ethanol organosolv lignins from Picea abies and Fagus sylvatica were carboxymethylated with bromoacetic acid. Of the total hydroxyl groups in the lignins, 60–70% were carboxymethylated. The reaction led to an increase of the number-average molecular weights. The moisture adsorption of the carboxymethylated products is about one and a half as high as that of the original lignins. There are no remarkable differences between the solubilities of the treated and untreated products.

Notes: Summary The reactions of quinone methide intermediates during the initial biosynthesis and also the subsequent aging of lignin are reviewed. The reactions during aging should lead to enhanced lignin-carbohydrate bonding and may explain the structural and analytical differences found between DHP and isolated milled wood lignins.

Notes: Summary Crystalline inclusions were observed in more than 50%, silica in nearly 20% of about 1500 wood specimens representing ±750 species from 40 genera of the laurel family. Both types of inorganic cell deposits are described and classified with regard to composition, habit, size, degree of isolation and location. Their diagnostic value and taxonomic implications on the specific, generic and suprageneric level are discussed with respect to intra as well as extrafamiliar relationships.

Notes: Summary The longitudinal permeability of Abies grandis wood swollen to varying degree by water vapour sorption has been measured using a non-swelling liquid. The results obtained show that cell wall swelling causes a reversible decrease in permeability in both air dried and solvent exchange dried specimens. Direct microscopic measurements have shown that change in lumen diameter cannot explain the observed effect. Mathematical analysis of the data suggests that the permeability decrease may be due to increase in thickness of bordered pit membrane fibrils resulting from sorption of water.

Notes: Summary Slow speed wood cutting tests were carried out in which cutting forces were measured as a function of applied tool-work electrical potential. The cutting tool and workpiece were electrically insulated so that there was no current flow. Applied potential had no discernible effect on the cutting forces measured in the cutting of unextracted and extracted wet wood.

Notes: Summary The acoustic velocities of a wide range of particle boards were determined from measurements of the transit times of wave packets through the materials. Velocities measured along the plane of the board are dependent on the properties of the board's skin layer, and are reasonably well correlated with the board's modulus of elasticity (r=0.73) and modulus of rupture (r=0.65). Velocities measured perpendicular to the plane of the board are not so well correlated with the mechanical properties of the board — the most significant being the Z strength parameter (r=0.56). The results suggest that this form of non destructive testing would be more suited to production line monitoring than to replacing or complementing existing test methods.

Notes: Summary The study is concerned with the possibility of demonstrating in the transmission electron microscope components such as copper, chromium and arsenic of preservative salts in the wood cell walls using secondary reactions with chemicals. Among the 18 substances tested only 9 showed a substantial positive effect, which was established on the basis of the electron contrast or depositions obtained within the various wall layers. It is suggested that copper is adsorbed onto the matrix substances of the wood cell wall rather than on cellulose.

Notes: Summary The reduction in hygroscopicity as spruce wood is impregnated with linseed oil may be accounted for using a molecular exclusion model. On the basis of the model, each linseed oil molecule appears to displace 90 water molecules and occupy 6 hydrogen bonding sites in the wood.

Notes: Summary Kraft pulping is interpreted in chemical terms on the basis of results from extensive qualitative and quantitative model experiments. In essence, the behavior of lignin is explained as a competition between degradation reactions, mainly involving aryl ether cleavage with participation of neighboring groups, and condensation reactions, comprising conjugate addition of carbanions to quinone methide intermediates. The initial phase of technical delignification is tentatively ascribed to the cleavage of α- and β-aryl ether bonds in phenolic lignin units, whereas the cleavage of β-aryl ether bonds in non-phenolic lignin units is considered to be the rate-determining reaction of the bulk phase. The residual phase may possibly be attributed to the rupture of C-C linkages and to aryl ether cleavage without neighboring group participation. Experimental support for these correlations is provided. The interplay of the various lignin reactions, illustrated in a summarizing scheme, explains some known observations in kraft pulping. Attention is drawn to analogies between reactions involved in the degradation of carbohydrates and those reponsible for the degradation of lignin. From the chemical standpoint, therefore, the selectivity of delignification is due to differences in the reactivity of the wood polymers, rather than to differences in the mechanisms of the degradation reactions. This fact explains the limitations of selective delignification.

Notes: Summary Previous methods for measuring residual longitudinal growth strain distributions in logs are reviewed. An extension is given of Jacobs' method for measuring growth strains which yields residual strain information at many points in the cross section other than along the diametrical plank. Some of the longitudinal growth strain distributions measured using the new method are presented.

Notes: Summary A method for the derivatization of low molecular weight lignin acidolysis product by reduction-acetylation is described. Borane dimethyl sulfide complex has been used as reducing agent. The derivatives could be analysed by gas chromatography.

Notes: Summary Geographical location (north/south latitude), social position of trees in a forst stand (dominant, codominant, suppressed) and site quality were investigated as to their effect on tracheid length, proportion of latewood and wood density of black pine indigenous to Greece. Tracheid length was fund greater in the northern location, in dominant trees and at intermediate site qualities. Proportion of latewood was higher in the southern location, in suppressed trees and at intermediate site qualities. Density was higher in the southern location, in codominant trees and at good or intermediate site qualities. Statistically, however, many differences at P = 95 % and all differences at P = 99% are not significant. The present study is based on the sampling of 331 trees, 55 years old and older; the probes were taken only from the 10 outer rings, at breast height. The findings from 6 trees, sampled from pith to bark, present disagreement with the above results.

Notes: Summary The viscoelastic deflection resulting from load increasing continuously from 30% stress level (linear range) to 60% stress level (non-linear range), i.e., within the proportional limit was measured over a period of 10 h. The experimental deflection could be predicted by a numerical method using model element constants which were an experimentally determined function of stress level. An 8-element model consisting of a Maxwell model and three Voigt models in series was used. The upper limit of stress level where a linear relation between creep strain and stress holds ranged from about 35% to 40%. Calculated deflections agreed well with experimental deflections.

Notes: Summary Two equations are derived to describe the nonisothermal unsteady-state diffusion of moisture in one direction in parallel-sided bodies. One equation is based upon a gradient of activated moisture molecules and the other on a gradient of chemical potential.