Morphological study of the testes of the dove Columba livia (Gmelin) (Columbidae, Columbiformes)

Known as "domestic dove", the Columba livia (Gmelin, 1789) is a columbidae species widely distributed in Brazil, whose reproductive biology has been studied by many researchers. The testes of 12 Columba livia males were collected and prepared for histologic examination under an optical microscope, the results of which were analysed and photographed. The tunica albuginea that covers the testes consists of a thick, not very cellular layer of dense connective tissue. Groups of interstitial cells with typical morphological appearance and surrounded by loose, well vascularized connective tissue are observable within the organ, between the seminiferous tubules. The seminiferous tubules are thick, intensely wound and, when seen in cross section, show Sertoli cells and spermatogenic lineage cells in different stages of development. These include spermatogonia (type A, clear; type A, dark; and type B), spermatocytes I and II, spermatids, and a large number of spermatozoons. Similarities are found between the histological findings described and those reported for the testes of Columbina talpacoti (Temminck, 1811)

Histologia geral dos intestinos do Caiman crocodilus yacare (Daudin, 1802) (Crocodilia: Reptilia)

<abstract language="eng">General histology of small intestine (duodenum and jejunum) and the large intestine (colon and cloaca) of C. c. yacare (Daudin, 1802) Crocodilia-Reptilia. A comparative description is made of the histology of the small and large intestine of C. c. yacare. In all segments mucosa, submucosa, muscularis and serosa tunics were observed. The duodenum as very long villi, wich are well-developed and attached together to form irregular transverse ridges, covered with simple columnar epithelium with marginal and goblet cells. In the jejunum, the villi are shorter and less frequent. The colon as few folds, covered with the same epithelium; the lamina própria contains straight tubular glands with absortive cells, goblet and Paneth cells. The cloaca is very complex, with three well-defined regions: coprodeum, urodeum and proctodeum. In the coprodeum, the wall is folded, less muscular and the thin mucosa is covered by an epithelium with a few basal cells and mucosal cells. The urodeum as an additional external muscular tunic, with striated muscle fibers and a stritifield cylindrical epithelium with goblet cells. The proctodeum includes the free part of the penis in the male and, laterally, the ducts of a pair of holocrine cloacal glands. Near the opening of the ducts, the epithelium changes to a squamous keratinized type