586 AMPHIBIA. 



(ve) — coming from the testis, fall into a canal known as the longitudinal 

 canal of the Wolffian body, from which there pass off transverse canals, 

 which fall into, and are equal in number to, the primary Malpighian 

 bodies of the sexual part of the gland. The spermatozoa, brought 

 to the Malpighian bodies, are thence transported along the segmental 

 tubes to the Wolffian duct, and so to the exterior. The system of 

 canals connecting the testis with the Malpighian bodies is known as 

 the testicular network. The number of segmental tubes connected 

 with the testis varies very greatly. In Siredon there are as many as 

 from 30—32 (Spengel). 



The longitudinal canal of the Wolffian body is in rare instances (Spe- 

 lerpes, etc.) absent, where the sexual part of the Wolffian body is slightly 

 developed. In the Urodela the testes are united with the anterior part of 

 the Wolffian body. In tlie Cceciliidfe the junction takes place in an homo- 

 logous part of the Wolffian body, bnt, owing to the development of the an- 

 terior segmental tubes, which are rudimentary in the Urodela, it is situated 

 some way behind the front end. Amongst the Annra the connection of 

 the testis with the tubules of the Wolffian body is subject to considerable 

 variations. In Bufo cinerens the normal Urodele type is preserved, and 

 in Bombinator the same arrangement is found in a rudimentary condition, 

 in that there are transverse trunks from the longitudinal canal of the 

 Wolffian bo(]y, which end blindly, while the semen is carried into the 

 Wolffian duct by canals in front of the Wolffian body. In Alytes and 

 T.'iscoglossus the semen is carried away by a similar direct continuation of 

 the longitudinal canal in front of the Wolffian body, bnt there are no 

 rudimentary transverse canals passing into the Wolffian body, as in Bombi- 

 nator. In Rana the transverse ducts which pass off from the longitudinal 

 canal of the Wolffian body, after dilating to form (1) rudimentary Mal- 

 pighian bodies, enter directly into the collecting tubes near their opening 

 into the Wolffian duct. 



In most Urodeles the peritoneal openings connected with the primary 

 generative Malpighian bodies atrophy, but in Spelerpes they persist. In 

 the Cceciliidae they also remain in the adult state. 



With reference to the development of these parts little is known 

 except that the testicular network grows out from the primary Mal- 

 pighian bodies, and becomes united with the testis. Embryological 

 evidence, as well as the fact of the persistence of the peritoneal funnels 

 of the generative region in the adults of some forms, proves that the 

 testicular network is not developed from the peritoneal funnels. 



Rudiments of the testicular netwoi-k are found in the female Coeciliidse 

 and in the females of many Urodela (Salamandra, Triton). These rudi- 

 ments may in their fullest development consist of a longitudinal canal and 

 of transverse canals passing Irom this to the Malpigldan bodies, together 

 with some branches passing into the mesovarium. 



Amongst the Urodela the collecting tubes of the hinder non-sexual 

 part of the Wolffian body, which probably represents a rudimentary meta- 

 ne{)hros, undergo in the male sex a change similar to that which they 

 usually undergo in Elasmobranchii. Their points of junction with the 

 Wolffian duct are carried back to the hindermost end of the duct (fig. 



