ALBERT

Notes: Summary The crustacean class Mystacocarida is restricted to the interstitial marine sand environment. A cinemicrographic analysis of the functional morphology of locomotion in the mystacocarid D. typica was undertaken to demonstrate how this species progresses through the interstitial spaces. Locomotion is completely dependent on the presence of dorsal and ventral substrates. The biramous second antennae and mandibles are the force-generating appendages. During a locomotory cycle, the exopods of the second antennae and mandibles are directed dorsolaterally against a dorsal substrate. This creates a downward force enabling the endopods to gain purchase on the ventral substrate. The second antennae and mandibles undergo coordinated cyclic movements. Each cycle results in two power and two recovery strokes. The animals undergo approximately 4 complete cycles per second. The calculated maximum rate of locomotion is 420 μm/s. The measured rate under test conditions is 250 μm/s. A turning-escape reaction in response to air bubbles and other factors results in a 180° turn in a confined space within 1.5 s. These data are discussed in relation to the morphological conservatism of mystacocarids, their presumed neotenic origin and their observed migration over a tidal cycle. It is proposed that all crawling interstitial animals will have developed specific mechanisms to increase frictional forces between their locomotory appendages and the surrounding substrate.

Notes: Summary The fine structure of the ocellus of Sarsia tubulosa is described. The ocellar cup is formed of pigment cells and receptor cells. The receptor cells outnumber the pigment cells in almost a 2:1 ratio. Lateral extensions of neighbouring pigment cells enclose a distal region of 2 to 10 receptor cells. The receptor cell body is 5–7 μm in diameter with an apical extension (20–60 μm long) that reaches the ocellar cavity. A cilium (9+2 microtubules) arises from the distal part of the receptor cell. The ciliary membrane forms lateral microvilli. The tips of a number of cilia are swollen into large vesicles forming a “cornea”. The central region of the ocellar cavity contains extracellular electron dense homogeneous material surrounded by swollen ciliary tips and small vesicles. The close apposition between the plasma membrane covering the distal part of adjacent receptor cells as well as the adjacent ciliary shafts suggests the presence of gap junctions. The basal part of each receptor cell forms an axon. The axons of receptor cells form 3 to 4 nerve bundles that join to form the optic nerve. Synapses occur between receptor cell bodies, between axons and receptor cell bodies and among axons.

Notes: Summary In Rhapidostreptus virgator exocrine gland complexes are found in the anal valves of both sexes. Every gland complex consists of about 200 secretory units, each of which is comprised of four cells: two secretory cells, an intermediary cell, and a canal cell. The amount of secretion produced by these glands varies during the intermoult cycle: it is very small in freshly moulted individuals (postmoult phase), at a medial level during the following intermoult phase, and very large in the premoult phase. The secretion may be used to form the excrement clumps and above all to build the moulting chamber.

Notes: Summary The skin vascularization was investigated troughout the ontogenetic development and in adults of two anurans, Rana temporaria and Bufo bufo, and two urodeles, Triturus vulgaris and Triturus cristatus. It was found that, contrary to the urodele larvae, the anuran tadpoles have a very sparse skin vascularization. During the early stages of anuran metamorphosis the skin capillary network becomes dense; later, during skin metamorphosis, a second, venous, network is formed as anastomoses between the subcutaneous vein ramifications. In the urodeles, metamorphosis is not accompanied by any significant morphological changes in the skin vascularization, and a subcutaneous network is not formed. It is suggested that the reduced skin vascularization in anuran tadpoles is an advanced larval character relative to the rich vascularization of the skin in urodele larvae. It is further suggested that anuran tadpoles have a reduced ability to utilize gaseous exchange through the skin. The function of the subcutaneous venous network found in anurans after metamorphosis is obscure; experiments indicate a vasomotor regulation which is neither adrenergic nor cholinergic.

Notes: Summary The larval morphology of the marine bryozoan Bowerbankia gracilis has been investigated by light and electron microscopy. The barrel-shaped larva (200 μm long and 150 μm in diameter) is light yellow without any apparent eyespots, although it is positively phototactic during its brief free-swimming existence. The primary morphological characteristics of the larva are: (1) a large corona that forms most of the larval surface, (2) a small apical disc without blastemas, (3) a deep pallial sinus lined by an extensive pallial epithelium, (4) an internal sac without regional specializations, and (5) a polypide rudiment in the oral hemisphere. This organization is characteristic of larvae of the ctenostome superfamily Vesicularioidea, and differs radically from the organization of all other bryozoan larvae examined. The major morphological differences occur in the size and organization of the apical disc, the pallial epithelium, and the internal sac. In most bryozoans, these regions of the larval epithelium represent rudiments of the polypide and the body wall epidermis of the ancestrula. The oral polypide rudiment, the extensive pallial epithelium, and the reduced internal sac in vesicularioid larvae indicate that their pattern of metamorphosis also differs radically from the metamorphoses of other bryozoans.

Notes: Summary A sponge (Ephydatia fluviatilis L.) embedded in styrol methacrylate was cut into pieces with a fretsaw. One piece was then soaked in xylene to remove the polymer, dried in the critical-point dryer, gold-coated and finally examined in the scanning electron microscope. The pictures obtained reveal the three dimensional arrangement of the cells in the sponge, through the openings in the cut surface.

Notes: Summary The organization of the female genital apparatus of the bdelloid rotifer Philodina roseola was analyzed by light and electron microscopy. It differs from that of the monogononts in several respects: the gonad is paired; in each gonad, the follicular layer completely surrounds the syncytial vitellarium and the cluster of ovocytes; the cytoplasmic bridges between the vitellarium and the immature ovocytes exist but are much narrower; a specialized junction (5–8 nm intercellular space) is established between the follicular layer and the whole area of the germo-vitellarium complex. Preliminary observations about the movements of organelles during ovogenesis were made at an ultrastructural level.

Notes: Summary An ultrastructural study of the tentacles of Themiste lageniformis (Sipuncula) was conducted as part of a larger study of head metamorphosis in the species. The oral surface of the tentacles is constructed of a multiciliated, pseudostratified, columnar epithelium while the aboral surface is an unciliated, cuboidal epithelium. Intraepidermal mucous cells lie near the junction of the oral and aboral regions. The basal portion of the epidermal cells is embedded in a thick, collagenous extracellular matrix which contains outer circular muscles, inner longitudinal muscles, the main tentacular nerve and its branches. Three tentacular canals are present and are lined by peritoneum. Hemerythrocytes and coelomocytes flow through the lumen of the canals in a regular pattern. Justification for the designation of the tentacular canals as coelomic rather than vascular is discussed.

Notes: Summary The coxal organs of different Geophilomorpha were studied by scanning and by transmission electron microscopy. 1) The coxae of the last trunk-segment contain pores in different arrangements and numbers. They are the openings of the coxal organs. 2) The coxal organs are formed by four different cell types: the main epithelium consists of radially arranged transporting cells, surrounded by junctional cells, gland cells, and the cells of the pore channel. 3) The cells of the transporting epithelium show an enlargement of the apical and basal surface. Deep and narrow extracellular channels of the apical infoldings are closely associated by mitochondria (plasmalemma-mitochondrial complexes). The epithelium is covered by a prominent cuticle with a spacious subcuticle. 4) A distinct mucous layer covers the cuticle of the transporting epithelia, and is secreted by the gland cells. 5) A small cellular sheath separates the epithelium of the coxal organ against the haemolymph. 6) The possible function of the coxal organs in ion and fluid transport is discussed.

Notes: Summary Each pigment-cup eye of Polycystis naegelii consists of two retinal clubs and a single pigmented cell. The latter is divided into two cavities by a septum. Under bright illumination the photoreceptor process appears as a disk containing membranous laminar whorls; under faint illumination the latter are replaced by numerous straight, closely packed, microvilli. This morphological variation is correlated with the intensity of the photoreceptor's exposure to light. The lenticular structures described by previous light microscopists have not been observed.

Notes: Summary The microstructure of the surface of thirteen marine littoral and two terrestrial isopods was investigated by scanning electron microscopy. A great diversity of surface ornamentation is present, including non-sensory microscales, pits, tubercles, and ridges, and sensory tricorns, pit organs, pores, papillae and setae. Microscales are common features of the integument surface; their shape and size are highly variable. Tricorns were not observed on the marine littoral isopods. Several hitherto undescribed structures were observed including spade-like projections from the tergite surface of Oniscus asellus, hair-like filaments associated with the microscales of Jaera and ridged conical protuberances on Edotea triloba and E. montosa. The possible function of certain surface microstructures is discussed.

Notes: Summary Two cells which lie at the left and at the right near the anterior end of Cirrifera aculeata (Ax, 1951) (Proseriata) are interpreted as presumed photoreceptors. In the left cell up to 70 slightly modified cilia extend into a large intracellular cavity. Besides these cilia microvilli and electron-dense granules are present. The presumed light sensitive structures of the right cell are formed by tubular vacuoles which are arranged without gaps, thus comparable to the microvilli of a rhabdom. The functional and evolutionary aspects of these two cell types are discussed.

Notes: Summary The settlement and metamorphosis of the marine bryozoan Bowerbankia gracilis has been examined by light and electron microscopy. The period of rapid morphogenesis consists of the following sequence of morphogenetic movements: 1) eversion of the internal sac, 2) retraction of the apical disc, 3) coronal involution and exposure of the pallial epithelium, and 4) closure of the internal coronal cavity. The eversion of the internal sac at the onset of metamorphosis coincides with a sudden reversal of the direction of beat of the coronal cilia. The reversed beating of the coronal cilia wafts the adhesive secreted by the internal sac over the metamorphosing larva, forming the pellicle. The internal sac is subsequently internalized and histolyzed with the corona and the other transitory larval tissues, and the extensive pallial epithelium forms the epidermis of the ancestrular body wall (cystid). Type I mesenchyme cells form an incomplete somatic mesothelium beneath the differentiating cystid epidermis, and Type II mesenchyme cells become mobile phagocytes. The main body cavity develops by the histolytic enlargement of the internal cavity formed during coronal involution. The apical disc degenerates and the polypide develops from rudiments in the oral hemisphere of the larva. The distinctive larval morphology and metamorphosis of vesicularioid ctenostomes are compared with other bryozoans, and possible evolutionary trends are considered.

Notes: Summary Ultrastructural study of the buccal tentacles of Holothuria forskali revealed that each tentacle bears numerous apical papillae. Each papilla consists of several differentiated sensory buds. The epidermis of the buds is composed of three cell types, i.e. mucus cells, ciliated cells, and glandular vesicular cells (GV cells). The GV cells have apical microvilli; they contain bundles of cross striated fibrillae associated with microtubules. Ciliated cells have a short non-motile cilium. Bud epidermal cells intimately contact an epineural nervous plate which is located slightly above the basement membrane of the epidermis. The epineural plate of each bud connects with the hyponeural nerve plexus of the tentacle. This nerve plexus consists of an axonic meshwork surrounded in places by sheath cells. The buccal tentacles have well-developed mesothelial muscles. Direct innervation of these muscles by the hyponeural nerve plexus was not seen. It is suggested that the buccal tentacles of H. forskali are sensory organs. They would recognize the organically richest areas of the sediment surface through the chemosensitive abilities of their apical buds. Tentacles presumably trap particles by wedging them between their buds and papillae.

Notes: Summary Only one non-ciliary proprioceptor is developed on the mandible of Thrips. It consists of two bipolar, multiterminal sense cells, the dendrites of which form a strand extended between the tentorium and the back mandibular margin. The dendritic terminals are embedded in an electron-dense, homogeneous matrix, which obviously represents the stimulus transmitting structure. The strand is stretched, if the mandible is moved forwards and upwards. In Thrips, the system of proprioceptors monitoring the mandibular movement is reduced extensively compared with other pterygote insects. This is linked up with the far-reaching reduction of the mobility of the mandible itself.

Notes: Summary The nephridia of Ophryotrocha puerilis are segmental organs. The nephrostome opens at the posterior margin of a setigerous segment into the coelomic cavity of this segment. The nephridial canal is made up of about 15 cells. These cells form an S-shaped tubule which extends into the following segment. The lumen of the nephridial canal ranges from 2 to 7 μm in diameter. The nephropore opens laterally on the ventral surface of the body wall. In cross sections, one, two, or three cells are seen forming the canal. The inner surfaces of the canal cells are of different appearances along the canal. Since no regular pattern of cell distribution was found along the canals of different nephridia it is assumed that changes in cell structure along the canal are due to functional states or properties rather than to anatomically fixed regional differences. The canal cells either show smooth contours or they form brush borders of microvilli or sponge-like inner surfaces with a system of vacuolar canals running through the cytoplasm. Most of the canal cells are filled with various kinds of vesicles. Usually two or three cells contain larger vesicles up to 2.5 μm in diameter with more or less electron-dense contents. Some of these vesicles resemble lysosomes. There are at least three bundles of cilia in each canal. In young specimens the number of cilia in one bundle is smaller (10–15) than in adult specimens (60–70). The nephridia do not show sex specific differences. The female nephridia do not function as genital ducts. As judged from the sizes of sperm and nephridia it appears to be possible that sperm are shed via male nephridia.

Notes: Summary Spermiogenesis of the architectonicid Philippia (Psilaxis) oxytropis was studied using transmission electron microscopy. Both spermatids and mature sperm of Philippia show features comparable to sperm/spermatids of euthyneuran gastropods (opisthobranchs, pulmonates) and not mesogastropods (with which the Architectonicidae are commonly grouped). These features include: (1) Accumulation of dense material on the outer membrane of anterior of the early spermatid nucleus — this material probably incorporated into the acrosome; (2) Structure of the unattached and attached spermatid acrosome (apical vesicle, acrosomal pedestal) accompanied by curved (transient) support structures; (3) Formation of the midpiece by individual mitochondrial wrapping around the axonemal complex, and the subsequent fusion and metamorphosis of the mitochondria to form the midpiece; (4) Presence of periodically banded coarse fibres surrounding the axonemal doublets and intra-axonemal rows of granules. A glycogen piece occurs posterior to the midpiece but is a feature observed in both euspermatozoa of mesogastropods (and neogastropods) and in sperm of some euthyneurans. Despite the lack of paracrystalline material or glycogen helices within the midpiece (both usually associated with sperm of euthyneurans), the features of spermiogenesis and sperm listed indicate that the Architectonicidae may be more appropriately referable to the Euthyneura than the Prosobranchia.

Notes: Summary The exopodal branches of the pleopods of Cyathura carinata have a thicker cuticle than the endopodites, but the hypodermis proved to be very thin and probably of respiratory function. The nuclei are found in ‘pilaster areas’ together with stabilizing elements (micro-tubuli attached to cuticular pegs), which are typical for hypodermal ‘tendon cells’ of other arthropods. Precipitation of Ag2S revealed that the cuticle of the exopod is more permeable to silver ions than the cuticle of the endopods. The endopodal epithelia have the features of typical osmoregulating tissues (apical folds, mitochondrial pumps, and basal invaginations of the plasma membrane) and reduce silver nitrate. The stabilizing ‘pilaster areas’ are composed of the same elements as in the exopods.

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 In larvae of Diplosoma macdonaldi one sensory nerve extends along the dorsal midline of the tail and another extends along the ventral midline. Each nerve is composed of 50–70 naked axons lying in a groove in the base of the epidermis, and each projects to the visceral ganglion. The cell bodies of the caudal sensory neurons occur in pairs within the epidermis, and are situated along the courses of the nerves. A single cilium arises from an invagination in the soma of each neuron, passes through the inner cuticular layer of the tunic and enters a tail fin formed by the outer cuticular layer. We propose that these cells are mechanoreceptors. The caudal sensory system is similar in representative species of ten families of ascidians.

Notes: Summary Modified branchiostegal rays 1 through 3 support the proximal end of the paired hyoid barbels in the beardfish (Beryciformes: Polymixiidae). The polymixiid barbel is unusual in that it has an unique intrinsic muscular system. Using silver impregnation and electron microscopic techniques, unencapsulated, free nerve endings were located within the tendon of the third modified branchiostegal ray. Branchiostegal rays 1 and 2 do not have any free nerve endings associated with their tendons, however. It is suggested that the free nerve endings are proprioceptors acting as stretch-sensitive mechanoreceptors, and that branchiostegal ray 3 acts as part of a sensory apparatus for monitoring the positional state of the barbel. Branchiostegal rays 1 and 2 merely provide support for the barbel.

Notes: Summary The skeletal rods of the gill bars of Branchiostoma have been examined histochemically and electron microscopically. The rods are composed of 15-nm thick filaments which are interconnected by 10-nm thick and 15-nm long cross-linkages. The filaments appear to consist of structural proteins that are totally different from the proteins of the collagen fibrils. The cross-linkages between the filaments consist of acid mucopolysaccharides, and probably include chondroitin sulphate. The fine structure of blood vessels in the gill bars has been studied in uninjected specimens and in those intravascularly injected with either india ink or horseradish peroxidase. Blood vessels surrounded by basal laminae of delimiting epithelia or simply surrounded by connective tissue material are present in the gill bars. Very characteristic blood cells are normally found in these vessels. Furthermore, when either india ink or horseradish peroxidase is injected via the aorta and the endostylar vessel, irregular slitlike channels can be seen in the connective tissue. These channels are in open connection with the blood vessels and are thus a part of the vascular system.

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 The exposure of wood treated with a commercial fire retardant chemical to fire conditions resulted in different patterns of char and fissure development than are seen in untreated whole wood. In addition microstructural observations demonstrated the existence of particulate fire retardant residues in char from treated wood. The source and mode of growth of these particles is considered as well as effects of fire retardants on crack growth, char development and overall appearance of chars from treated wood.

Notes: Summary Tar and charcoal could be produced in high yields from bagasse by applying a rapid continuous pyrolysis process at a relatively low temperature. The ether extractives of the pyrolytic tar and oil amounted to 9.4% based on bagasse. Phenols represented 79% of these extractives. Gas chromatographic separation showed that guaiacol and its derivatives constituted 38% of the identified simple phenols. There were much smaller amounts of syringol and none at high pyrolysis temperatures. Depithing did not reduce the ash content of the charcoal, but it yielded an environmentally clean charcoal containing practically no sulfur or nitrogen. It was necessary to remove the fine particle size fraction of the bagasse after grinding in order to reduce the ash content of the charcoal. The carbon content of the charcoal increased rapidly with increasing temperature, and reached 96% at 720°C. The charcoal had a remarkably high adsorption capacity despite the fact that it had not been subjected to any activation treatment.

Notes: Summary The alkaline delignification of spruce and beech wood is accomplished in three phases. The first phase results in a decrease of yield down to 83...80%, the second one in a decrease from 83...80% to 64...61% and the third one in a yeld drop from 64...61% to 50...46%. The amount of polysaccharides removed in the first phase was 22%, in the second phase 5...6% and in the third phase 10% of the total polysaccharides in the original wood. The amount of lignin removed in the first phase of delignification was 9...11% in the second phase 53...54% and in the third phase 28% of the total lignin in the original wood. The polysaccharides extracted in the second and third phase amounted to 70...78% of the polysaccharides removed in the first delignification phase. For an entire characterization of the delignification reaction not only the course of lignin removal is of importance but also the course of the polysaccharide extraction. The results show that for a two-stage alkali-oxygen-cooking technology the optimum yield after initial partial alkaline delignification lies in the range of 64...61%.

Notes: Summary Delignification studies on 0.5 μm sections of Douglas-fir earlywood tracheids pulped by soda, soda-anthraquinone (soda/AQ) and kraft pulping processes were performed by determining bromine concentrations in various morphological regions with SEM-EDXA technique. Soda/AQ pulping was much more selective in removing lignin from the middle lamella regions than either soda or kraft pulping. However, up to 50% delignification, more lignin was removed from the secondary wall by soda or kraft, compared to soda/AQ pulping. The kinetics of lignin removal in the various morphological regions were established. Addition of AQ and sodium sulfide resulted in an earlier transition from a slow initial to a rapid bulk delignification, particularly in the middle lamella, and in an enhanced bulk delignification in the secondary wall. Anthraquinone was also found to promote residual delignification in the secondary wall, where sodium sulfide was not effective. The opposite was observed for the bulk delignification in the middle lamella, where only sodium sulfide addition improved the rate significantly. The great differences observed in the bulk delignification rates between middle lamella and secondary wall in soda pulping as well as their response to additives suggest structural differences between middle lamella and secondary wall lignins.

Notes: Summary The lignification process in different morphological regions of loblolly pine tracheids was studied by the SEM-EDXA technique. Prior to S2 layer formation, lignification was initiated in the cell corner middle lamella and compound middle lamella regions. Subsequently a rapid lignin deposition was observed in both regions, whereas secondary wall lignification was a more gradual process and initiated when the middle lamella lignin concentration was approximately 50% of maximum. Within the secondary wall, the S1 layer is lignified first. Then, lagging just behind cell wall formation, lignification of the S2 layer is initiated adjacent to the S1 layer and extends toward the lumen. Finally, the S3 layer lignified. Upon completion of lignification, the cell walls had a higher concentration of lignin in both the S1 and S3 layers than in the S2 layer.

Notes: Summary Photodegradation of wood surfaces in the presence of oxygen was studied. ESR studies revealed that free radicals were formed at the wood surface during photoirradiation. These wood free radicals readily interacted with oxygen molecules to form peroxide radicals. Iodometry UV absorption studies showed that hydroperoxide was formed in the photoirradiated wood. The hydroperoxide concentration increased when wood was irradiated in the presence of singlet oxygen generators such as Rose Bengal and Methylene Blue. Hydroperoxide concentration decreased when wood was irradiated in the presence of singlet oxygen quenchers such as 1,4-diazobicyclo (2,2,2) octane, β-carotene and triethylamine. These findings imply the participation of singlet oxygen in the photodegradation of wood surfaces. The mechanisms of formation of singlet oxygen and hydroperoxide during photoirradiation are proposed. The consequence of hydroperoxide decomposition reactions on the discoloration and degradation of wood surface is discussed.

Notes: Summary This paper concerns the elaboration of a method for the determination of elastic constants of orthotropic bodies with particular application to wood. It is based on the finite element calculation (displacement pattern) of thin plate samples and on the experimental measurement of the deflections at particular points under a simply imposed load.

Notes: Summary The reaction of enzymatically generated superoxide radical with coniferyl alcohol in aqueous solution at pH 8.0 was studied. In the absence of calcium (II) no reaction occurred, but with a calcium (II) concentration of about 50 mM or more, coniferyl alcohol was oxidized by the superoxide radical. Dehydrodiconiferyl alcohol and pinoresinol were identified in the reaction mixture. From this result it is concluded that in the presence of calcium (II) the superoxide radical can achieve a one electron oxidation of coniferyl alcohol. It is suggested that a superoxide-generating enzyme outside the cell wall is responsible for the lignification. This suggestion is based on knowledge of the pore structure of wood cell walls, the high calcium concentration in non-lignified cells, the course of lignification and the existence of superoxide-producing enzyme systems in plant cell walls.

Notes: Summary A review of the chemistry and topochemistry of compression wood with 200 references. Compression wood contains on the average 30% cellulose, 35–40% lignin, 10% galactan, 9% galactoglucomannan, 8% xylan, and 2% of a 1,3-glucan (laricinan). The cellulose is less crystalline, and the xylan has fewer arabinose side chains than in normal wood. The lignin is composed of guaiacylpropane and p-hydroxyphenylpropane units. It is more condensed, has a higher proportion of carbon-carbon bonds, and contains fewer arylglycerol-β-aryl ether structures than a normal conifer lignin. The ray cells and the primary wall of the tracheids have the same chemical composition in normal and compression woods. The galactan is largely located in the outer region of the secondary wall. Only 5–10% of the lignin in compression wood tracheids is extracellular. The middle lamella is less lignified than in normal wood, while the S1 and inner S2 layers have a lignin concentration of 30–40% which is twice as high as in normal wood. The lignin content of the S2 (L) layer is equal to or higher than that of the intercellular region along the wall. The review is concluded with a brief reference to areas where present information is incomplete or lacking.

Notes: Summary A model for the isothermal transport of bound water through the cell wall of wood is developed, based on the assumption that the driving force for moisture movement is the gradient of “spreading” pressure ϕ, as first proposed by Babbitt (1950). This pressure is a surface phenomenon, derivable from the surface sorption theory of Dent (1977), a modification of the BET sorption theory. The force resisting moisture transport is assumed to be inversely proportional to moisture content and directly proportional to the equivalent viscosity of the sorbed water, calculated to be orders of magnitude larger than that of free water. The coefficients normally used to describe isothermal moisture transport in wood are derived from the model, and their predicted behavior as functions of the relative vapor pressure h of the cell wall are described graphically. An attempt is made to calculate a quantitative magnitude for the diffusion coefficient D, based on an assumed relationship between viscosity and the activation energy for water diffusion.

Notes: Summary To elucidate biochemical features leading to p-hydroxyphenyl-rich lignin in gymnosperm reaction wood the activities of the following five enzymes involved in the biosynthesis of p-hydroxyphenyl lignin were compared in reaction and opposite woods: phenylalanine ammonialyase (EC 4.3.1.5), cinnamate 4-hydroxylase (EC 1.14.13.11), p-hydroxycinnamate: CoA ligase (EC 6.2.1.12), cinnamyl alcohol dehydrogenase (EC 1.1.1.-) and peroxidase (EC 1.11.1.7). The enzyme activities in the reaction woods of Thuja orientalis and Metasequoia glyptostroboides were remarkably higher than those in the opposite woods, reflecting the higher contents of p-hydroxyphenyl lignin in reaction wood.

Notes: Summary The purpose of this paper was to clarify the gluability and adhesion mechanism of polypropylene as a hot melt wood adhesive for plywood bonding. The gluability of plywood glued with nonpolar and modified polypropylene satisfied approximately the specification of the Japan Agricultural Standard, Designation Types 1 and 2. The moisture content (8 to 25 %) of the core veneer had no recognizable effect on gluability. The durability of polypropylene and that of modified polypropylene were the same as that of melamine-formaldehyde resin. Molten polypropylene made good contact with veneer surface, and penetrated into the lumina of wood cells and other spaces. In the separated glue lines, casts of glue which had penetrated into the vessels had many mushroom-like projections which had filled the bordered pit cavities. It was indicated that the anchoring effect of polypropylene which had penetrated into various wood elements and spaces in the veneer contributed dominantly to the gluability.

Notes: Summary The anatomy of periderms in three North American conifers are described and compared. The phellems of balsam fir and eastern hemlock consist of tangential bands of thin-walled phellem (TnP) separated by one, or sometimes more, cell layers of thick-walled phellem (TkP). The phellem of white spruce contains tangential bands of TnP and TkP, as well as one to several cell layers of crystalliferous phellem (CP) abaxially adjacent to every TkP zone. The TkP, and to a lesser extent the TnP, are distinctive for each of the three conifers. The terminations of phellem growth cycles in fir and hemlock are delineated by thickened adaxial suberinic walls in the last-formed layer of TnP cells. In spruce, the adaxial suberinic walls of the last-formed layer of CP cells are thickened. TkP marks the geginning of phellem growth cycles in all three conifers. TkP cells are “true” suberized phellem cells, not phelloids.

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 integument of Oncopeltus fasciatus is made up of a vacuolated and a pigmented epidermal cell layer. This double layered integument is present from late embryo to adult in male and female animals reared on milkweed or sunflower seeds. Experiments with a labelled glycoside as well as retrograde ink injections suggest that O. fasciatus concentrates cardiac glycosides, normally derived from the host plants, within the vacuolated epidermal cell layer throughout its life cycle. In the adult, droplets of glycoside-rich fluid appear at precise points along the dorsolateral margins when external pressure is applied to the thorax and abdomen. This pressure causes separation of cuticular flanges in the metathoracic epimeral lobe and rupture of the cuticle in restricted areas in the mesothorax and abdomen. In addition the pigmented epidermal cell layer and the distal membranes of the vacuolated epidermal cell layer rupture with the result that the contents of the vacuolated cell layer are eliminated onto the surface of the animal where they are retained as discrete droplets by the cuticular morphology. Release of cardiac glycosides into the haemolymph is prevented by a thick basal lamina on the haemolymph side of the vacuolated epidermal cells. No specialized muscles involved with fluid release were observed. The vacuolated epidermal cells do not show ultrastructural features characteristic of actively transporting tissues, i.e., abundant mitochondria and elaborate membrane infoldings. This suggests that glycoside sequestration is essentially a passive process and should not be associated with any physiological cost. Large concentration gradients of cardiac glycosides are maintained across the basal lamina, basal plasma and vacuolar membranes of the vacuolated epidermal cell layer. Possible mechanisms by which O. fasciatus is able to concentrate cardiac glycosides as well as the possible function of this phenomenon are discussed.

Notes: Summary In the buccal ganglia of Helix pomatia synapses and sites of possible release of neurosecretory material were investigated electron microscopically. There is one chemical synapse and one electrotonic synapse in the neuropile of the ganglion. No synapses could be detected in the buccal nerves, cerebro-buccal connectives, or in the buccal commissure. The synaptic cleft of the chemical synapse is about 25 nm wide and contains electron-dense material whereas the cleft of the electrotonic synapse is only 5 nm wide. The presynaptic fibre of the chemical synapse contains clear vesicles and dense core vesicles. The release sites of neurosecretory material are found at the initial segment of the axons, at perikarya of neurones, and at the perineurium of the ganglion. If the terminals are located at the plasmalemma of a nerve cell, these release sites are called synapse-like structures according to Roubos and Moorer-van Delft (1979). The synapse-like structures show all structural elements of synapses, except the 25 nm cleft containing dense material; the cleft is only 15–20 nm wide here like the normal cleft between neurones and glial cells or between two fibres. If the secretory material is released at the periphery through the perineurium the terminal is called synaptoid according to Scharrer (1970). In all cases, i.e. synapses, synapse-like structures, and synaptoids, clear vesicles were found in the axon terminal. This finding provides further evidence that clear vesicles always accompany the release of substances from axon endings.

Notes: Summary A closing apparatus of the Dufour gland is described in the formicine ant Formica sanguinea Latreille 1798. Four sets of muscles are involved, two of which directly attach to the slit-like duct. The latter shows a considerable cuticular thickening of its intima at this level. Ultrastructural observations reveal that the muscles are attached to a cuticula by means of intracellular microtubules in the duct cells. These microtubules run parallel to the myofilaments. Together with the increased contact area for muscular attachments they are believed to ensure the accurate muscular mechanism assuring a well-controlled spraying activity of this gland. Opening of the duct is probably achieved by active muscular contractions, while its closure may be achieved by a passive return to the rest position of the thickened cuticular intima.

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 A method has been developed for the determination of lignin distribution in wood cell walls by studying bromine concentrations in 0.5 μm sections with scanning electron microscopy coupled with energy dispersive X-ray analysis (SEM-EDXA) technique. Evaluation of backscattering, absorption and fluorescence effects on quantitative assay of lignin distribution indicated that these effects may all be ignored, if relative comparisons are made. Thus, a relative ratio of the measured Br-L X-ray intensities directly provides bromine concentration ratio, from which the ratio of lignin concentrations in different morphological regions can be estimated. Additionally, the effect of electron beam bombardment on bromine was found to be negligible. Therefore, the SEM-EDXA technique provides quantitative information of lignin distribution with relatively high accuracy. The potential and limitations of this technique were also elucidated.

Notes: Summary Acoustic emission (AE) monitoring is a non-destructive testing technique widely used to detect flaw development and crack propagation in metals, ceramics, polymers and composite materials. This paper relates the AE-strain characteristics from three softwoods tested in tension to mechanisms of deformation observed by scanning electron microscopy. All wood specimens are identical in size and radial-longitudinal in orientation, enabling the path of failure through planes of earlywood and latewood to be examined. It is found that the proportion of earlywood to latewood in each species has a marked effect on the shape of the AE-strain curves. Parana pine, containing very few latewood tracheids, exhibits a close to linear relationship between log cumulative emissions and strain until close to failure when the count rate increases rapidly. Douglas-fir, which has well-defined earlywood-latewood boundaries generates many AEs at low strain and there is greater variation in the shape of the AE characteristic between samples. Parana pine and Douglas-fir are tested at 20 °C (12.5 % EMC). Scots pine is also stressed at 20°C (12.5%EMC), 20°C (0.7%EMC) and 80°C (0.7%EMC), to assess the effect of moisture content on AE. Values of Young's modulus, stress at failure and work of fracture for the three softwoods are compared with the AE-strain data. Although the work of fracture is related to the total AEs to failure, no direct proportionality exists between the two parameters. Finally, the AE-strain data for plywood and glass-reinforced plastic (GRP), both man-made composite materials, are compared with those of wood, the natural composite material.

Notes: Summary A reply to the note by Nimz (1981) on the occurrence of benzyl non-cyclic ether bonds in lignin.

Notes: Summary An extension is made to a previously proposed reliability-based procedure for characterizing the duration of load properties of wood. This extension provides a methodology for testing if two disjoint nominal populations of wood specified by modulus of elasticity have significantly different time to failure distributions at a given applied stress. This extension has practical application in the assignment of grades to structural lumber and in determining the dependence of time to failure on grade, species, and size.

Notes: Summary Structural changes in spruce and aspen wood samples subjected to axial compression were examined by means of the scanning electron microscope. For comparison, macroscopic model experiments were carried out on tube-shaped samples made of paper so as to represent segments of fibriform xylem cells. The results show that there are fracture patterns characteristic of wood in general and others characteristic of the species of wood. The phenomena characteristic of wood in general are prevalent at the cellular level and in the fracture behaviour of the cell wall layers and perforations. The characteristics of the various species of wood dominate at the level of the growth rings and are decisively influenced by the composition and arrangement of the tissues. The model experiments show that the failure morphology of the individual cells of the xylem may be explained to some extent by their geometry.