102 



C.sir. 



lo tlie morphology of llie testis liihnles of newly mefaniorpliosed frogs. 

 After describing' the development of tlie so-called indifferent gonad 



— which possesses a germinal epithelium consisting of one layer 



and surrounding a central lumen, the 

 primary genital space, in which cell-strands, 

 the sexual stiands, situated at regular 

 distances behind each other, have origin- 

 ated from the mesoiu^phros — Witschi 

 traces the development of the ovary and 

 the direct testis-development. The indirect 

 testis-development, which takes place in 

 the so-called hermaphrodites of 

 Pflügkh is elaborately described ; in tliis 

 case the testis originates from an ovarium- 

 like gonad ^). As this development does 

 not bear directly upon my subject and 

 as the final stage of both direct and 

 indirect testis-development is the same, 

 I will not enter any further upon this 



„, , question. Shortly, the direct testis-develop- 



Fig. 1. ^ -^ ^ 



o , • J 1 .• J- 1 ment is as follows. The germ cells leave 

 öcliematized longitudinal " 



section of the testis of a newly ^^'^ germinal epithelium, wander through 

 metamorphosed frog. After the primary genital space and settle on 

 Witschi (1914). the sexual strands. All germ cells leave 



the germinal epithelium about simultaneously, so that only the 

 peritoneum remains. Between the germ cells and the compact core 

 of the sexual strands several slits originate: the anlages of the 

 lumina of the testis-ampullae. Then the ampullae diff"erentiate from 

 each other and in this way the anlages of the testis tubules develop. 

 These ampullae are short, almost globular tubules, with a lumen 

 disappearing later on. 



The convex side of the ampullae is directed towards the periphery 

 of the testis; with the other side they are attached to the central 

 strand. The sexual strands are connected with the mesonephros. The 

 distal ends of these strands thicken, fuse and in this way the central 

 strand originates in the longitudinal axis of the juvenile testis. After 

 some time the inner-testicular network or rete testis originates from 

 the central strand, as well as the vasa efïerentia from the compact 

 sexual strands. 



A scliematized longitudinal section of the testis of a newly meta- 



1) WiTSCHi's latest publication (1921) treats the same subject. 



