. Elements of the comparative anatomy of vertebrates. Anatomy, Comparative. 366 COMPARATIVE ANATOMY wards the kidneys, and opens into a longitudinal canal. From the latter the sperm passes through a second system of transverse canals to the Malpighian capsules, and thence through the urinary tubules into the urinogenital duct. The male generative apparatus of all Urodela and certain Anura (comp. p. 354) corresponds in the main with that seen in -Ceecilians, except as regards the form of the gonads : thus the testis is either pointed at one or both ends (Fig. 279), or more or less round or oval
. Elements of the comparative anatomy of vertebrates. Anatomy, Comparative. 366 COMPARATIVE ANATOMY wards the kidneys, and opens into a longitudinal canal. From the latter the sperm passes through a second system of transverse canals to the Malpighian capsules, and thence through the urinary tubules into the urinogenital duct. The male generative apparatus of all Urodela and certain Anura (comp. p. 354) corresponds in the main with that seen in -Ceecilians, except as regards the form of the gonads : thus the testis is either pointed at one or both ends (Fig. 279), or more or less round or oval (Figs. 280, 292). In Rana, Bombinator, and Alytes the vasa efferentia of the testis become gradually separated from the kidney: that is, they either open directly into the urinogenital duct, without becoming connected with the urinary tubules. Pig. 292. -Testis and Anterior End of Kidney op Rana escuhnta. (Semidiagramjnatic.) -Ho, testis ; q, q, transverse canals of the testicular network, which give rise to blmd processes a,t i-f ; L, longitudinal canal of the testicular network from which the interrenal network (C, C) arises ; xV, kidney; Ur, urinogenital duct. (Rana, Fig. 292), or the greater number of the posterior canals end Mindly, while only the anterior ones are directly connected with the urinogenital duct (Bombinator). In Alytes the relations of the generative ducts require further investigation. Miillerian ducts are always present, but they always remam in a more or less rudimentary condition in the male, and lie along the outer border of the kidneys m a similar position to those of the female. They may or may not be provided with a lumen and apertures of communication with the body- cavity and cloaca. Heimiqjhroditkm occasionally occurs amongst the Anura : only one case (Triton tfeniatus) is known amongst Urodeles. A body attached to the anterior end of the testis in various species of Toads ("Bidder's orcran ") is apparently capable of giving rise to ova
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectanatomycomparative
