50 AMPHIBIA CHAP. 



interrupted and the vestiges of the transverse canals are no lonuvr 

 functional. The eggs fall into the body-cavity and are caught 

 up by the ostium or inner abdominal opening of a special duct, 

 the oviduct (Miillerian duct of many authors). Vestiges, more or 

 less complete, of these oviducts persist in the males of most 

 Amphibia. 



This general scheme presents some modifications in the 

 various groups of Amphibia. 



The Apoda retain the most primitive conditions. The kidneys 

 are still long and narrow, and the glomeruli are, at least in the 

 anterior part of the organ, still strictly segmental, agreeing in 

 number and position, each with a vertebral segment ; later, the 

 number of the glomeruli is greatly increased, and the former 

 agreement becomes quite disturbed. The generative glands still 

 retain their segmental arrangement, but they are restricted to 

 a much shorter region than the kidneys. In the male Apoda a 

 considerable portion of the cloaca can be everted by special 

 muscles, and acts as an intromittent organ. Both sexes possess 

 a ventral urinary bladder. 



In the Urodela both kidneys and testes are much concentrated, 

 the testes especially have lost all outward appearance of seg- 

 mentation, and their efferent canals, connecting them with the 

 longitudinal collecting canal, are much reduced in numbers. The 

 greater portion of the kidneys, at least their anterior half, has 

 all the appearance of a degenerating organ and is on the way to 

 losing its urinary function, although it still possesses Malpighian 

 bodies and complete ducts ; the main function of the latter is 

 now the conveyance of the sperma. In the Perennibranchiata, 

 'and in some others, e.g. Spelerpes variegatus, the longitudinal 

 collecting canal, between testis and kidney, is sometimes sup- 

 pressed, a very simple, but pseudo- primitive arrangement. A 

 urinary bladder is present. The cloaca is not eversible. 



In most Anura, e.g. Rana and Bufo (Fig. 7 ; 4, 5), the same 

 scheme is adhered to. The efferent canals of the testis form a 

 network, with a longitudinal canal, and open into the efferent 

 canals of the kidney, in the substance of which they are more or 

 less deeply imbedded. The ducts which lead out of the kidney 

 to compose Leydig's duct, are frequently dilated, or the latter 

 duct is much elongated, convoluted or varicated, and this whole 

 portion is enclosed in a sheath of connective tissue, giving an 



