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1998).Since the lingual papillae of the domestic ruminant show an extreme variety of shape, webelieved it interesting to extend the study to innervation of the lingual papillae of the waterbuffalo, analyzing the morphological, structural, and immunohistochemical characteristicsof the gustatory papillae.MATERIALS AND METHODSThe study was performed on 25 water buffalo fetuses of both sexes, from 5 to 60cm inlength, and originating from a local slaughter-house. The fetus length, from the sinciput tothe tail root, was utilized as a development index. The fetuses were subdivided into fivegroups in relation to their length (5–7cm; 10–15cm; 20–25cm; 30–35cm; 40–60cm). Foreach group samples were prepared for scanning electron microscopy (SEM), transmissionelectron microscopy (TEM), light microscopy (LM), and the simple immunohistochemicalmethod.The TEM samples were treated by the usual techniques.

The morpho-functional and topographical features of the lingual papillae situated on the dorsal surface of the bovine tongue, were studied utilizing LM and SEM techniques. In the bovine species, the functional differentiation of the lingual papillae in their gustatory and mechanical modes, seems to be related to the position of the papillae rather than to their morphological features. The gustatory function predominates over the mechanical one on the caudal tract of the tongue body (lateral to the lingual torus and associated with circumvallate papillae). The gustatory function also involves the conical papillae situated on the caudal tract of the tongue body. This gustatory function is aided by additional anatomical structures: 1. The grooves situated on the rostro-lateral side of the conical papillae; 2. The microcraters located on the top of the fungiform papillae; and 3. The furrows of the circumvallatae papillae vallum. The contact between saliva soluble food particles and taste buds is aided and made more efficient by these structures. Furthermore, a large variety of conical papillae were observed, whereas no filiform papillae were noted.

The innervation of the Syrinx was studied in 15 female Peking Ducks of 10 to 12 months old by using L.M. and E.M. In this organ a nervous plexiform net is present located in the connective below the epithelium along the membrana tympaniformis medialis. This net-work is made of the nervous trunks which repeatedly anastomise among themselves and display during their course acapsulate ganglions. However, no specialized contact device were encountered at the periphery.

The morphological and structural aspects of the Membrana tympaniformis medialis of the syrinx were studied with L.M. and E.M. in 32 female and male Peking ducks from 6 to 12 months old. The membrane is covered by pseudostratified prismatic epithelium which shows different regional features. While at level of the proximal and distal third of the tympanic membrane the morphological and structural aspects of the cells resemble that of the adjacent structures (pessulus and primary bronchi), the middle part of the epithelium layer becomes gradually flattered; the epithelium is made up of oblique or horizontal cells which touch each other by means of many lateral interdigitations. At level of the upper parts of the cells there are several types of cell junctions. This particular disposition seem to be well adapted to the contractions of the syringeal muscles.

The immunolocalization of S100-like protein was investigated in the kidney of saltwater fishes (Dicentrarchus labrax; Coris julis; Serranus cabrilla; Scorpaena porcus), amphibia (Rana aesculenta), reptiles (Lacerta viridis), and aves (Gallus domesticus; Strutio camelus). S100-like immunoreactivity was detected in the juxtaglomerular cells of all saltwater fishes studied. No immunoreactivity was observed in other tracts of the nephron or in the interstitial tissue. In frog kidney, S100-like immunoreactive cells were localized in the proximal tubule, singly distributed or placed side by side in clusters of two or three cells. S100-like immunoreactive cells were distributed in the distal and in the collecting tubules in lizard, chicken, and ostrich kidney. In the distal tubule of lizard kidney, S100-like immunoreactive cells were numerous and uniformly distributed. In lizard collecting tubules, S100-like immunoreactive cells showed less intense immunoreactivity than in the distal tubule, except for a cluster of cells at the junction with the initial collecting duct. In chicken and ostrich kidney, S100-like immunoreactive cells of the distal tubules were closely packed together. In the collecting tubules, S100-like immunoreactive cells were alternate to negative cells. These results indicate the high conservation degree of S100 proteins through phylogenesis and suggest a functional role for these proteins in the vertebrate kidney.

Neuropeptide Y-immunoreactive (NPY-ir) fibers and neurons in the brain of the domestic chick (Gallus domesticus) were described using an immunohistochemical technique. NPY-ir neurons were seen in the lobus parolfactorius; hyperstriatum, neostriatum, paleostriatum, and archistriatum; hippocampal and parahippocampal areas; dorsolateral corticoid area; piriform cortex; two thalamic areas contiguous to the n. rotundus; n. dorsolateralis anterior thalami, pars lateralis, and pars magnocellularis; n. periventricularis hypothalami; n. paraventricularis magnocellularis; regio lateralis hypothalami; n. infundibuli; inner zone of the median eminence; dorsal and lateral portions of the n. opticus basalis; n. raphes; and n. reticularis paramedianus. NPY-ir fibers were seen throughout the entire chick brain, but were more abundant in the hypothalamus where they formed networks and pathways. They were also observed in some circumventricular organs. The anatomical data of the present study regarding the distribution of NPY ir in the chick brain, together with the physiological findings of other studies, suggest that NPY plays a key role in the regulation of the neuroendocrine, vegetative, and sensory systems of birds by acting as a neuromodulator and/or neurotransmitter. Anat Rec 263:186–201, 2001. © 2001 Wiley-Liss, Inc.

Summary The morphology of the ureter of the duck was investigated, using histological, SEM and TEM techniques. The inner perimeter, the total thickness of the ureteral wall and the thickness of each uretral layer were measured. The epithelium was tall columnar and pseudostratified along all the tracts of the ureter and showed a high muco-secretive activity. The lamina propria contained numerous capillaries and aggregates of leucocytes and macrophages. Throughout the lamina propria there was a dense plexus of nerves. Some denuded single nerve fibres were observed between the epithelial basal cells. A plexus of nerves was also observed in the tunica muscularis. The ostium cloacale ureteris opened on a well-developed papilla in the dorsal region of the urodeum. The total thickness of the ureteral wall, the thickness of the lamina propria and the tunica muscularis, and the inner perimeter progressively increased towards the ostium. The above observations suggest that the avian ureter plays an important role in the modification of the urine coming from medullary cones, and in emission of the urine into the cloaca.

Summary On the Structure of the Clavicular Air-Sack of the Duck The structural organization of the epithelium lining the clavicular air sac in Duck was studied by light and electron microscope. This epithelium consists of two types of pavement like cells. The first flat types of cells are numerous with large mitocondria containing cytoplasm and elongated nuclei. The second short and dumpy cells are few in number and are after seen near the ostium. They could have long microvilli like pseudopod on their apical surface ready to engulf inhaled foreign particles. Desmosomal bridges too are found between contiguous cells.

Summary On the involution of the bursa of Fabricius of the duck The morphological and structural aspects of the functional aspects of the involution were studied light- and electronmicroscopically in ducks 90 to 150 days old. The first involutionary changes were observed in the interfollicular connective tissue around day 100. Following this, cells left the periphery of the follicles; they were connected with collagen fibers and positioned themselves between the lymphocytes of the cortex that became thinner before it disappeared. On day 135 the medulla lost its lymphocyte content through wide ducts which opened directly into the lumen of the bursa. On day 150 the bursa experienced a massive overgrowth; almost all follicles had disintegrated and only small groups of cells remained which consisted principally of reticuloepithelial cells and some lymphocytes. Cysts were not observed during the involution of the bursa.

The palatine tonsil was studied comparatively on 10 heads each of ox and buffalo. On latex casts the branches of the tonsillar sinus were demonstrated. Histological study included the epithelium of the tonsillar sinus, the connective tissue of capsule and septa, the lymphatic tissue and intra and extracapsular glandular lobules

The morphological and structural features of the vascular component of the bursa of Fabricius in the duck are described. By means of an intravasal perfusion of suitably colored neoprene Latex or Microscopaque, or a perfusion of Indian ink, it was possible to follow visually the routes of arteries, veins and the microcirculation; this last represents a major characteristic of the bursal follicle in the duck. The microcirculation has its origins in several roots arising from the follicular arterioles, which in the region of the cortex constitute an open vascular layer. From these pre-capillary arterioles, adjacent to the limiting layer between cortex and medulla, a dense capillary network is formed. With the aid of an electron microscope the presence of a cortico-medullary barrier of an epithelio-reticular nature was revealed; close to it there are the terminal branches of the intrafollicular network. The barrier appears to be structurally more compact than that of the cortical capillaries of the mammalian thymus.

IN earlier investigations, we have demonstrated1 that the injection of 100 µgm. of calcium pantothenate into the yolk sac of chicken eggs after incubation periods of 4 and 10 days is responsible for an increase in body-weight, lasting 3–6 days. Together with the increase in body-weight, we have observed also an increase in tissue differentiation (studied by means of serial histological examination) especially of the nervous system (ganglia), kidneys, glandular stomach, liver and cartilages.