The present study was conducted on the sternum of an eight year old, male Green-winged Macaw. The sternum was quadrilateral with dorsal concave and ventral convex surfaces and four borders. The dorsal surface presented numerous pneumatic foramina. The ventral surface furnished a large, boat shaped keel. The anterior extremity showed two facets for coracoid. The anterior and posterior borders were convex. The lateral border on either side presented six costal facets. Two distinct oval foramina were seen near the posterior border. Craniolateral processes were short and stump-like. Caudolateral processes fused with the median trabecula on either side. The rostrum was distinct. The morphological features of the sternum of Green-winged Macaw conformed to that of flying group of birds. It was almost similar to that of goose in its anterior half and to that of pigeon in its posterior half.

Morphological studies were conducted on the skull of a hippopotamus brought to the Veterinary college for postmortem examination. Skull of the hippopotamus was huge and notable for its little brain case and high supra-orbital ridges. The skull had a larger splanchnocranium than the neurocranium. From the dorsal view, the skull had a watch glass appearance because of its narrow middle portion (at the region of maxillae) and wide caudal and rostral portions. Maxilla showed a large Eminenta canina and two infraorbital foramina leading to two separate infraorbital canals. The premaxilla lodged two huge incisors and just above the central incisor, there was a large rough eminence for the elevated nostrils. Three to four large rounded lacrimal bullae were seen on the floor of the bony orbit. Frontal bone presented a strongly convex smooth supra-orbital ridge that formed upper margin of the orbit which projected from the surface of the skull. The median sagittal crest was very high that diverged to accommodate the concave forehead in front. Temporal fossa was very extensive. Caudal surface of the skull showed a concave nuchal surface and the external occipital protuberance was in the form of a crest. The paramastoid process and external auditory process were very short. Bulla tympanica was conical with a pyramidal muscular process. Anatomical peculiarities of the skull and their functional significance are discussed.

Gross and histological studies were conducted on the pharyngeal tonsil of six male crossbred goats of six months of age. In the nasopharynx, pharyngeal tonsil was located on the caudal part of the pharyngeal septum and was 5.54±1.41cm long and 2.19±0.92cm wide. It presented numerous longitudinally arranged primary and secondary folds. Histologically the tonsil was lined by pseudostratified ciliated columnar epithelium comprising of 8-14 rows of nuclei of three types of cells, viz. basal, supporting and goblet cells. This epithelium was transformed at places into follicle-associated epithelium (FAE) and was characterized by decreased height of the epithelial cells, absence of cilia and goblet cells and heavy infiltration of lymphocytes through the interrupted basement membrane. The height of surface epithelium was 87.33± 1.20μm and that of follicle-associated epithelium was 52.33± 5.21μm. Propria-submucosa comprised of a central axis of loosely arranged connective tissue with dense aggregates of lymphoid tissue, fine blood capillaries and few nerve fibres folded around it. The cryptolymphatic units and tonsillar nodules of varying shape and dimensions constituted the majority of the lymphoid tissue. The average diameter of lymphoid nodules was 921.67±8.72μm and the lymphocyte count per nodule was 32233.23±324.24. The average number of lymphatic nodules counted per field under low power magnification of microscope was 2.5±0.43 and the internodular distance was 29.83±1.40μm. In scanning electron microscopy surface of the pharyngeal tonsil was covered by two types of epithelium viz., the ciliated respiratory surface epithelium and the FAE consisting predominantly of three types of non-ciliated microvillus cells.

Aim:To observe the light and scanning electron microscopy (SEM) of the caprine tubal tonsil.Materials and Methods:The study was conducted on six crossbred male goats of 6 months of age. From the median sections of the head, tissue pieces from the nasopharynx around the auditory tube were collected and fixed for histology and SEM.Results:Tonsillar lymphoid tissue was located in the nasopharynx ventral to the auditory tube opening in the lateral wall of the pharynx. The height of the surface epithelium of the tubal tonsil measured 80.17±1.08 µm and was a pseudostratified ciliated columnar type with basal, supporting, and goblet cells. Above the dome of lymphoid nodules, the epithelium was modified into a follicle associated epithelium (FAE), also called lympho-epithelium or reticular epithelium and was characterized by the absence of goblet cells and cilia, reduced number of cell layers, and a large number of lymphoid cells due to interrupted basement membrane. The height of FAE was smaller than that of the surface epithelium and measured 34.33±0.92 µm. The surface of tubal tonsil showed folds and invaginations, which formed crypts. The lamina propria-submucosa underneath the epithelium was formed by the meshwork of reticular and, thin and loose collagen fibers with dome-like accumulation of lymphoid nodules. In the secondary lymphoid nodules, a corona, parafollicular area, and interfnodular area were observed. The average number of lymphoid nodules counted per field under low power magnification of microscope was 1.17±0.17, and the internodular distance was 34.00±4.37 µm. The mean diameter of lymphoid nodules was 566.67±11.45 µm and the lymphocyte count per nodule was 14741.67±174.36. The number of plasma cells counted per field under low power was 44.38±2.90 below the surface epithelium. The tubal tonsil was not encapsulated. In SEM, the surface epithelium of the tubal tonsils presented ciliated cells, microvillus (MV) cells, and goblet cells. The region of FAE possessed Type-I and Type-II MV cells and microfold (M) cells in between.Conclusion:It was concluded that the tubal tonsils were well developed in goats, which might serve as a means of protection against the spread of infection to the middle ear cavity.

The morphology and postnatal development of isthmus region of the oviduct in the Kuttanad