Ill 



vasa efferentia, ruiiiiing close to each other, fuse near tlie kidney. 



The left testis is remarkable for the following facts (fig. 11/). 

 The most cranial vas efferens runs like the most cranial ones, sketched 

 in fig. llrt and lib; the third vas efferens runs like both cranial 

 efferent duels of fig. lie and lie/ and moreover, a short side-duct 

 (N*. 2), coming from the fatbody, opens into it. The vasa efïerentia 

 N'^s 5 and 6 are close to each other, especially outside the testis, 

 but enter the mesonephros separately. The 7"^'' and 8''' vasa efferent ia 

 leave the rete testis united and split outside it; the 9''' vas efferens 

 finally is connected with the kidney, but does not reach the testis. 



So we have seen that the course of the efferent ducts in immature 

 frogs is as variable as in adult ones ami that there is nosymmeti-y 

 between left and right testis of the same animal. 



SUMMARY. 



I. According to Witschi the testis of a newly metamorphosed 

 Rana fusca is composed of a great number of short tubules, the 

 testis-ampuUae, which end blindly, and are implanted around and 

 perpendicular to a longitudinal stem, the central strand. With this 

 central strand the mesonephros is connected by the sexual strands. 

 The ampullae, which possess a lumen, disappearing later on, form 

 no anastomoses and are not branched. Later on the rele testis 

 originates from the central strand, the vasa efferentia fiom the 

 sexual strands. 



II. During the further development of the testis, the testis-ampidlae 

 increase in length as well as in diameter and they simultaneously 

 divide towards the periphery into a great number of branches, which 

 nearly all grow out till they reach the periphery. Only a few short 

 tubules, not reaching the testis-surface, were noted. 



III. The testis-tubules of an adult frog, are composed in the same 

 way: towards the periphery they split up more and more. All tubules 

 terminate in blind ends, and they never form anastomoses. The 

 tubules, which are straight near the perij)hery, are often somewhat 

 bent and twisted near to the rete. 



IV. In two testes of immature frogs it was observed that a small 

 caudal part of the testis is Jiot connected with the rete, but that 

 the tubules, composing it, opened directly into an efferent duel. 



V. The courses of the vasa efferentia of six immature frogs in 

 the beginning of the second year show several peculiaiities : 



1. A real netwoi'k, as in adult frogs, was not noted. 



2. In the fat-bod}' short tubules often occur, neilher connected 

 with the testis nor with the kidney. 



