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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.

Summary The goat choroid plexus angioarchitecture of the lateral ventricles was studied under the SEM using the method of “microvascular corrosion casts”. The whole plexus is semilunar shaped and directed in an antero-posterior, latero-median fashion. In the plexus the lateral extremity is larger than the median one. All the components of the vascular bed (arteries, venes and capillaries) of the choroid plexus have interesting morpho-structural features. In particular, the capillaries are more developed than the other components and they are variously located on both sides of the plexus. The capillary network has a various organization in different zones of each side of the plexus. Resume Grace a la technique des «microvascular corrosion casts», on a etudie l'angioarchitecture des plexus choroides des ventricules lateraux de l'encephale de la Chevre. Les moulages complets de ces formations se presentent sous la forme d'une demi-lune disposee obliquement dans un sens rostro-caudal et latero-medial et dont l'extremite caudo-laterale plus ample. l'observation en SEM des moulages vasculaires a mis en evidence la presence de caracteristiques morpho-structurelles particu-lieres au niveau des elements constitutifs des plexus choroides des ventricules lateraux. Les capillaires representent la composante la plus developpee, distribuee de facon variable sur chacune des deux faces du plexus choroide. Sur ces faces existent en effet plusieurs zones, ou les capillaires sont disposes de manieres differentes.

Summary Morphostructural characteristics of lingual papillae in buffalos The morphostructural characteristics of lingual papillae in 30 adult buffalos were studied by SEM. In this species, dorsal lingual surface papillae shos different shape so that their classification is complicated. Topography and morphology of conical and vallate papillae presents significant aspects. Particularly, the conical papillae have a different morphological organization when they are localized over the side of the tongue apex or over dorso-lateral tract of the tongue body. The functional aspects are discussed.

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.

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.