ALBERT

Notes: Abstract The process of pigmentation of oil-droplets in the retina of three reptiles has been investigated with regard to ontogeny. — The ability of these animals to perceive colors was tested on different stages of life. Young Lacerta vivipara, with still uncolored oil-droplets., show optomotoric reactions to colors.

Notes: Summary 1. The larval eye of the deep-sea fish Cataetyx memorabilis differs from the eye of the adult in several morphological facts: Its position is lateral, the shape is circular, the diameter is 30% of the head's length. (In the adult: position of eyes is dorsal, shape of eye is oval and the main axis corresponds to 8.3 % of the head's length.) 2. Anatomically 9 different retinal layers can be distinguished in the larval eye, with the bipolar cell—and the ganglion cell layer being the widest ones. 3. Ultrastructural investigations revealed grouped photoreceptors, rod-shaped pigment granules and lipid bodies in the choroid. 4. Serial sections allowed the reconstruction of the path of the optic nerve from the anterior-ventral part of the eye to the anterior-lateral zone of the brain. 5. Despite the larval character of the absence of outer segments, the larval eye seems to be suited for life in the mesopelagial, for it shows the typical adaptations to vision in twilight zones, e.g. enlargement of eye, pupil and lens; ratio of photoreceptor- to bipolar- to ganglion cell bodies 100:20:20 (i.e. grouped photoreceptors); absence of large posterior chamber and presence of lipid particles in the choroid.

Notes: Summary This new structure showed some of the caraeteristies of the basiconica olfactory senszlla — in the classification of Schneider and Steinbrecht (1968); but several original features appeared by electron microscopy study. The thickness of the cuticle is variable along the external process from the bottom to the tip: only the apical part bears ranges of pores; below (on 1 μ) the cuticle forms a thickening which defines two chambers; in each of them, it is possible that the olfactory perception is according to different modalities. The dendrites are branched and are certainly closed to the pore-tubules system. It is a polyneuronic receptor; the number of the sensory ells is upper than 30.

Notes: Summary From comparisons between bat wing structures and aerofoils and high-lift devices with known aerodynamic data, from the aeronautical literature, deductions are made regarding the function of some bat wing structures. Special arrangements in the hand wing add to rigidity and reduce the demands for powerful muscles and thick digits, thereby reducing the mass of the wing. 1. The anterior part of the wing, formed by the membrane parts anterior to the arm and third digit, is proportionally broad in megachiropteran bats as well as in many broad-winged microchiropteran bats. These parts can be lowered by the thumb and by pronation of the manus, and may together function as a leading edge flap. Leading edge flaps of aeroplanes permit, when lowered, higher angles of attack without separation, and thus higher lift coefficients. The leading edge in bats is very sharp, which increases the effectiveness of the leading edge flap. 2. The Reynolds number of bat wings lies in an interesting range, where the lift coefficient can be improved by induced turbulence of the boundary layer. The arm and digits, projecting markedly over the dorsal surface of the wing, and hair may function as turbulence generators. 3. The tension forces of the membrane on the digits have different effects upon the different digits, depending on the tautness of the surrounding membrane parts. The second digit and distal phalanx of the third digit are exposed mostly to bending in the membrane plane. The phalanges of the fourth and fifth digits are exposed to large dorsoventral bending. 4. Two arrangements add to relieving the distal part of the wing of large tension forces, thereby reducing the demand for a powerful extensor muscle of the distal phalanx (-ges) of the third digit: 1. The fourth and fifth digits act to alter the direction of tension. 2. By splitting the wing membrane in several parts by the digits, the second and third phalanges (the second in fruit-bats) of the third digit, which constitute the distal part of the wing's leading edge, are exposed to tension forces transformed from forces only from the nearest patagium. If the wing membrane would be outstretched only by one digit, as was the case in pterosaurs, the leading edge digit would have to resist the tension forces transformed from forces from the entire membrane posterior to the arm. 5. The fourth digit is angled in such a way that the proximal part of the membrane between the third and fourth digits is kept very taut, and the fourth metacarpophalangeal and interphalangeal joints are held very steady without any need of large muscular forces.

Notes: Summary This article deals with the gross and microscopic anatomy of the tongue and tongue region of the lower jaw of Gnathonemus petersii (Mormyriformes, Teleostei). The osteology coincides largely with that of Mormyrus caschive; the cranial muscles differ from those of most other fish through the absence of the m. intermandibularis posterior. The innervation of the tongue appears to be by the ramus palatinus superior n. facialis (VII). Microscopically the overall picture of the tongue is that of a deflated tube which consists at the outer portion of a compact continuous fibrous connective tissue surrounding an inner part which contains mainly loosely arranged collagen and reticular or elastic fibers with a few cells and little recognizable matrix. A comparison is made between the tongue structure of G. petersii and those of three other bony fish, Phoxinus phoxinus (Cyprinoidei), Plecoglossus altivelis (Salmonoidei) and Polypterus (Braehyopterygii).

Notes: Abstract The ultrastructure of a lateral organ in the head of Polyxenus lagurus which has been recently erroneously termed “cerebral gland” is described. It turned out to be a neurohaemal organ and not a gland, apparently homologous to the organ of Gabe of the luliformia.

Notes: Abstract Hitherto essential features of the hip musculature of the orang-utan are still not known completely, although they are of special interest for phylogenetical considerations. As a first step to a more complete knowledge of the muscular system of this animal the author clarifies the homologies of the superficial gluteal musculature on the basis of new dissections. The findings reveal important viewpoints for discusion on the phylogenetical interconnections between the Hominoidea.

Notes: Abstract The muscle and skeleton anatomy of the pectoral, pelvic, and anal fins are described in 3 Salariin Blenniidae: Salarias fasciatus (sublittoral), Istiblennius edentulus (eulittoral), Alticus kirkii (supralittoral). In A. kirkii these organs are adapted to a climbing habit on the steep rocks beyond the water. The results are compared with those found in Periophthalmus.

Notes: Abstract The neurosecretory cells (NSC) in the breeding phases show gigantic sized droplets. NSC show two peaks of activity in females at midnight and at 9 A.M., while a single peak occurs in males between midnight and 3 A.M. Light has a triggering effect on the neurosecretory release. The corpus cardiacum is the main neurohaemal organ. It has a nerve core formed by the nervi corpus cardiacum I and II, which is surrounded by the glandular region. Intrinsic secretory chromophilic cells and chromophobic cells occur randomly. Aorta is probably not a storage-release centre. The corpora allata are lobulated structures, showing cyclical activity which is correlated with egg-maturation. No neurosecretory material occurs in allatum.

Notes: Summary 1. The jaws of the family Gnathostomulidae have four major parts (fig. 80) : articularium, involucrum, dentarium, and suspensorium. 2. The articularium is highly specialized and fully freed from functions other than articulation of the jaws and the prevention of twisting motions. It consists of a symphysis lamella, joined by a symphysis in vertical position. 3. The involucrum is a specialization in the higher families of the Scleroperalia and the Austrognathiidae. In Gnathostomulidae it is of medium length with a well-defined caudal end, surrounding an apertura caudalis. From there a much thinner tectum lateralis continues. It is formed by a dorsal extension of the lamella interna which bends-as lamella externa-laterally and then ventrally, leaving only a fissure-like opening medioventrally: the incisura ventralis. 4. The dentarium consists of a thin lamella interna, which is always thickened in three portions, forming the arcus dorsalis, medialis, and ventralis. These arcs form the bases of the teeth. The arcus medialis also bears the strong dens terminalis. The dentation is more complicated and minute than the light microscope can resolve. An incisura dorsalis is found in few cases, cutting into the lamella interna from the caudal end. 5. The suspensorium is specialized into two portions: an anchorage part at the more fixed end., and an apophysis part nearer the moving ends of the jaw system. a) The cuticularized parts of the cauda system are always paired, but can be symmetrically or asymmetrically developed. In the first case the cuticularized caudae are tube- or cushion-like; in the latter case they are tubeshaped again, but a cauda dorsalis and a cauda ventralis can be distinguished. b) The apophyses are wing-shaped only distally, proximally they are differentiated (fibularized) into two fibulae functioning as cuticularized sinews: the fibula medialis originates at the ventrocaudal end of the lamella interna, the fibula lateralis at the ventral margin of the lamella externa. Together they form the fenestra ventralis, varying in dimension. c) In addition a fibula radialis is developed, strengthening the apertura caudalis of the involucrum. This fibula originates at the connecting point of the ventrocaudal end of the lamella externa and the fibula lateralis and it inserts in the caudal portion of the lamella interna either ventrally or dorsally. In the latter case it seems to be replaced by a sinew. Corresponding to its position it may bisect the fenestra ventralis into a fenester ventrocaudalis and ventrofrontalis and/or the apertura caudalis into a apertura caudolateralis and caudomedialis. 6. The basal plate is composed of three major parts: pars centralis, pars alaris, and the serrula. 7. The pars centralis forms a roof-like structure originating on the basis denticis, on top of the transverse axis, or the dorsum alae, of the wing system. A strong dens medialis forms the ridge of the roof, while groups of teeth form the margins. 8. The pars alaris consists of a dorsum alae—the stronger middle part, stretched in transverse direction. On both ends it bifurcates, thus forming five separate areas within the pars alaris: two are paired-the alae frontales and the alae laterales—and the unpaired mediocaudal portion, the tectum caudalis, which is much thinner. These portions seem to correspond to the widely representative five-partition of the alae in basal plates of Gnathostomulida. 9. The distal portion of the frontomedial margin of the alae frontales always bears a flat, scale-like dentation: the serrulae. Only in the genus Gnatliostomula does the proximal portion of this margin not end freely; it bends medially underneath the pars centralis. There the two sides meet and form an infundibulum. In this construction the originally paired serrulae continue proximally and fuse medially on the infundibulum.