258 VASA EFFERENTIA. 



Professor Semper states that there is but a single vas efferens 

 in Scyllium canicula, a statement which appears to me un- 

 questionably erroneous. All the vasa efFerentia fall into a 

 longitudinal duct (I. c), which is connected in succession wdtli 

 the several segments of the Wolffian body (one for each vas 

 efferens) which appertain to the testis. The hind end of the 

 longitudinal duct is simple, and ends blindly close to its junc- 

 tion with the last vas efferens; but in front, where the vasa 

 efferentia are complicated, the longitudinal duct also has a 

 complicated constitution, and forms a network rather than a 

 simple tube. It tj^pically sends off a duct to join the coils of 

 the Wolffian body between each pair of vasa efferentia, and is 

 usually swollen where this duct parts from it. A duct similar to 

 this has been described by Semper as Nierenrandcanal in seve- 

 ral Elasmobranchs, but its existence is expressly denied in the 

 case of Scyllium ! It is usually found in Amphibia, as we know 

 from Bidder and Spengel's researches. Spengel calls it Langs- 

 canal des Hoden ; the vessels from it into the kidney he calls 

 vasa efferentia, and the vessels to it, which I speak of as vasa 

 efferentia, he calls Quercanale. 



The exact mode of junction of the separate vasa efferentia 

 with the testis is difficult to make out on account of the opacity 

 of the basal portion of the testis. My figure shews that there 

 is a network of tubes (formed of four main tubes connected 

 by transverse branches) which is a continuation of the anterior 

 vasa efferentia, and joined by the two posterior ones. These 

 tubes receive the tubuli coming from the testicular ampullae. 

 The whole network may be called, with Semper, the testicular 

 network. While its general relations are represented in my 

 figure, the opacity of the testes was too great to allow of all 

 the details being with certainty filled in. 



The kidneys of Scyllium stellare, as might be expected, 

 closely resemble those of Scy. canicula. The ducts of the kidney 

 proper, have, in the former species, a larger number of distinct 

 openings into the urinogenital cloaca. In two male examples 

 I counted seven distinct ureters, though it is not impossible 

 that there may have been one or two more present. In one 

 of my examples the ureters had seven distinct openings into 

 the cloaca, in the other five openings. In a female I counted 



