Akbarsha, M.A., Kadalmani, B. and Tamilarasan, V. 2007. Efferent ductules of the fan-throated lizard Sitana ponticeriana Cuvier: light and transmission electron microscopy study. -Acta Zoologica (Stockholm) 88 : 265-274.Light microscopy histology of efferent ductules and the ultrastructural organization of their epithelium were studied in the fan-throated lizard Sitana ponticeriana Cuvier. The ductules of this lizard are extra-testicular and arise from an extra-testicular rete testis. A major portion of the ductules is intraepididymal and occupies the cephalic end of the epididymis. The ductules differentiate histologically into proximal and distal portions. The epithelium is formed of two major tall columnar cell types, the non-ciliated and ciliated, and one minor cell type, the basal cells. Dark cells were also identified. The non-ciliated cells possess microvilli towards the luminal end, tubular coated pits at the bases of the microvilli, coated vesicles in the apical cytoplasm and multivesicular bodies, lysosomes and mitochondria in the supranuclear and perinuclear cytoplasm, which reflects their role in the uptake of the material they are processing. These cells also participate in spermiophagy. The ciliated cells reflect their role in mixing the luminal content and/or its transport to the distal parts of the male tract. The lizard efferent ductules share many features in common with those of mammals and a crocodile and several other features with birds and a turtle. Spermiophagy by the efferent ductules is reported here for the first time in a reptile.

The epididymis of the fan-throated lizard Sitana ponticeriana was examined with light and transmission electron microscopy to understand the cellular mechanisms of fabrication of secretion granules in epithelial principal cells, granule release into the lumen, and the fate of the dense structured granules after reaching the lumen. Principal cells of the ductus epididymis, except at the cauda, secrete electron-dense biphasic granules copiously, which decrease in abundance from the initial segment to corpus. The principal cell possesses a prominent Golgi apparatus and all versions of endoplasmic reticulum (ER), rough, smooth, and sparsely granulated. The material of the dense portion of the secretion granules, after processing at the Golgi apparatus, appears to accumulate in large ER cisternae in the supranuclear cytoplasm. It undergoes condensation when the cisternae become condensing vacuoles. Mitochondria appear to play a role in dense granule formation. The condensing vacuoles are displaced toward the apical cytoplasm when the material of the less dense portion is added to the condensing vacuoles at the Golgi area. Thus, the less dense and dense portions of the secretion granules are secreted and added to the condensing vacuoles separately. The composite granules are released into the lumen by exocytosis when the less dense portion merges with the luminal content, whereas the dense portion maintains its structured identity. The latter, initially measuring 1-2 microm in diameter, increases in size several times. It is inferred that these granules release their content gradually, resulting in the appearance of vacuoles, and suggesting that the granules have an insoluble matrix in which there is a sparingly soluble material. The substance leaching out of the granules appears to contribute to keeping the sperm quiescent and alive during storage in the male reproductive tract.

Among reptiles, an ampulla ductus deferentis has been reported only in Squamata. Fairly detailed studies are available only for two species, the lizard Calotes versicolor (Fam: Agamidae) and the snake Seminatrix pygaea (Fam: Colubridae). The light microscopic study on C. versicolor revealed the ampulla to be a prominent organ, whereas the light and transmission electron microscopic study in S. pygaea revealed it to be discernable only in histological preparations. Further, the epithelium of the ductal portion of vas deferens as well as the ampulla of C. versicolor appears to contribute to the seminal plasma and can also phagocytose dead sperm, whereas in S. pygaea neither of these roles has been established. Thus, we hypothesize that there may be variations in the anatomy, histology, and the role of the vas deferens in general, and the ampulla in particular, of the squamate reptiles. In this study, the ductus deferens of the small fan-throated lizard Sitana ponticeriana (Fam: Agamidae) was subjected to light and transmission electron microscopic analysis. In this lizard the ampulla is more prominent than in C. versicolor. The epithelium of the ductal portion of vas deferens consists of principal cells (with features reflecting roles in endocytosis and phagocytosis of dead sperm), dark cells (which are absent in the epithelium of the ductal portion of vas deferens of snakes), and basal cells. The ampulla of S. ponticeriana is differentiated into storage and glandular portions. The epithelium of the storage portion is like that in the ductal portion of the vas deferens, whereas that of the glandular portion, consisting of dark and light principal cells and foamy cells, is tall and forms into smooth villous folds. All three cell types show evidence for a role in secretion, in all likelihood different from each other, for release into the lumen to contribute to seminal plasma. These cells do not provide evidence of a role in phagocytosis of dead sperm. It appears that within the Squamata, the ductal ampulla differs in structure as well as function. We suggest that the ductal ampulla of agamid lizards is a composite gland of the ampulla ductus deferentis and seminal vesicles of mammals.

 Abstract Akbarsha, M.A., Kadalmani, B. and Tamilarasan, V. 2006. Histological variation along and ultrastructural organization of the epithelium of the ductus epididymidis of the fan-throated lizard Sitana ponticeriana Cuvier. -Acta Zoologica (Stockholm) 87 : 181-196The epididymis of the fan-throated lizard Sitana ponticeriana was subjected to light and transmission electron microscopic analysis to find the histological variation along the ductus epididymidis, describe the various cell types in the epithelium and compare the resulting descriptions with what is known for other reptiles and for amniotes. The ductus epididymidis of this lizard is differentiated along its length into four histologically distinct zones, initial segment, caput, corpus and cauda. The first three zones appear to be associated with secretion and absorption/endocytosis whereas the cauda appears to be concerned with absorption/endocytosis and storage. The epithelium consists of six different cell types, principal, narrow, apical, clear, basal and intraepithelial leucocytes as in the mammals. Principal cells, basal cells and intraepithelial leucocytes are present along the entire length. Narrow cells and apical cells are confined to the initial segment whereas clear cells occur in the cauda only. The principal cells from the initial segment to the corpus produce biphasic secretion granules measuring 1-2 µ m in diameter. This paper reports on four histologically distinct zones along the length of the ductus epididymidis of the lizard S. ponticeriana and six different cell types in the lining epithelium.

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