Anatomy. — "(7n the morpliology of tlie testis of Ranafiisca Rösei" 

 By G. J. VAN OoKDT. (Oommiinicated by Prof. J. Boeke.) 



(Communicated at the meetiog of April 29, 1922.) 



Introduction. 



In recent yeai'S sevei-al investigations have given us a better 

 insight into the course and the structure of the seminiferous tubules 

 of a number of Mammals and of one Bird (cock). Formerly it was 

 tried to isolate these tubules by the process of maceration and teasing 

 in order to establish their form, their mutual relation and their con- 

 nection with the rete testis. The results were not convincing, however, 

 because it could not be traced with certainty whether the free ends 

 found were natural or had originated by tearing. 



By means of complete series of sections and wax-reconstructions 

 Bremer (1911) succeeded in disclosing the complicated structure of 

 the embryonic human testis. He discovered that the testis tubules 

 form a closed network. Employing a new, good injection method, 

 followed by maceration and teasing, Huber and Curtis (1913) isolated 

 in the testis of the adult rabbit several arch-shaped seminiferous 

 tubules, connected to the rete testis with both extremities. Besides 

 these simple "single-arched" (n-likej tubules, "double-arched" (m-like) 

 tubules, connected with the three free ends to the rete, were met 

 with. Relatively simple tubules as well as canal-systems of compli- 

 cated structure were found in the rabbit's testis; canals terminating 

 in blind ends or diverticula were not described, however. Applying 

 the same method Huber (1916) discovered in the testis of the cock 

 that the seminiferous tubules form a network, in which no blind 

 ends occur. 



Studying complete series of sections Curtis (1913) met with 

 various single-arched tubules in the testis of the mouse. Anastomoses 

 between two arches occur but rarily. Later on (1918) Curtis inves- 

 tigated the testes of mouse, rabbit and dog and in these animals he 

 also found the simple n-like tubule to be the original one. However, 

 the testis of the mouse shows the simplest structuie, then the testis 

 of the dog and next that of the rabbit follows as to com()lication. 



Independent of (Jurtis , de Burlet and de Ruiter (19^0) came to 

 the same results in studying a number of complete series of sections 



7 



Proceedings Royal Acad. Amsterdam. Vol. XXV. 



