1 68 Sex-Reversal in Frogs and Toads 



sexual characters generally approximated those of the typical male, the 

 seminal vesicles were also, almost without exception, as those of the 

 typical male. 



These facts suggest that there is some definite relation between the 

 nature of the gonads and the development of the accessory reproductory 

 apparatus. Cole's conclusion that "a good diagnostic feature as regards 

 sex is the seminal vesicle, which has only been observed in herma- 

 phrodites predominantly male" is justified, for it is seen that the 

 vesicles are commonly poorly developed or absent altogether in those 

 cases in the lists which were more female than male as regards their 

 secondary sexual characters and the nature of their gonads, in which a 

 considerable amount of ovarian tissue was present. In several cases the 

 vesicles were small or absent although there was no ovarian tissue pre- 

 sent in the gonads which were comjDOsed entirely of spermatic tissue. 

 In must of these cases unfortunately, the age of the individual and the 

 season of the year are not stated, and consequently a true estimate of 

 the importance of the condition of the vesicles cannot be made. Review- 

 ing the whole of the cases, however, it is seen that there is some con- 

 nection between the development of the seminal vesicles, and of the 

 vasa efferentia also, and the presence of spermatic tissue in the gonads. 



In this connection, it is noteworthy that Nussbaum in 1905 found 

 that the size of the seminal vesicles was controlled by the internal 

 secretion of the testis. 



It will be noticed that the degree of development of the seminal 

 vesicles and that of the vasa efferentia are connected, for in Cases 1 , 2, 

 3, 4, 5, 7, 12, both of these structures differ in degree of development 

 from those of the typical male, in that both were poorly developed. 

 Whatever affects the development of the one, therefore, also affects that 

 of the other. 



MiXllerian ducts. The degree of the development of these typically 

 female ducts in the cases tabulated varies from almost the rudimentary 

 condition normally found in the typical male— fine straight strands of 

 tissue as described by M tiller. Burro, and Rathke — to that of the fully 

 developed oviduct of the typical adult female. In 18 cases these ducts 

 were found to be well-developed, moderately well-developed in 2, 

 slightly or weakly developed in 6, in 5 other cases the development of 

 the ducts of the two sides was unequal. 



It will be seen that it is the rare exception for these ducts to be 

 anything but well-developed in those cases in the first half of the table, 

 that is, in those cases in which a considerable amount of ovarian tissue 



I 



