F. A. hi Crew 171 



There is, therefore, some evidence that the degree of development of 

 the Mullerian duct is controlled to some extent by the activity of the ovary 

 of the same side. It would seem that the Mullerian ducts are developed 

 under the direction of the ovaries, but that the degree of their develop- 

 ment in these cases is determined by the time during general development 

 at which the spermatic tissues first become expressed. If this is expressed 

 relatively early, then these ducts will not have attained their full de- 

 velopment, and their conditions will be as in Cases 14, 27, and 28. If 

 spermatic tissue becomes expressed even earlier still, then the ducts 

 will be as in Cases 20, 23, 29, 30, 31, and 32. If, on the other hand, this 

 expression is relatively later, then the ducts will have already attained 

 their full development and will retain their characters. 



In the cases in which these ducts were of unequal development, it 

 would seem that the process of transformation of ovary into testis began, 

 as is usual, in one gonad, and later extended to the other, and that the 

 interval between the beginning of the process in the two gonads was 

 prolonged, so that the duct of the side on which spermatic tissue had 

 yet to become expressed in the gonad would be permitted to develop a 

 little further, as the ovarian tissue of this side would be affected to less 

 extent than that of the other. 



A point of interest arises in Cases 30, 31 and 32. In Case 32 these 

 ducts had no posterior openings, while in the others they were solid in 

 their anterior portions. 



The Secondary Sexual Characters: 



Of the 30 frogs in the tables of which sufficient details were given 

 as to their secondary sexual characters 25 (83'3 "f^) were definitely and 

 typically male. Four others were definitely but imperfectly male 

 (13'3 °/J, and in the remaining case the secondary sexual characters 

 were female (3*3 "/J. 



In every case functioning spermatic tissue was present, and in those 

 cases in which ovarian tissue was also present, and in which sufficient 

 description of its histological structure was given, it has been shown 

 that this tissue was pathological and undergoing removal. 



The presence of imperfectly developed male secondary sexual cha- 

 racters is not associated with the development of female characters as is 

 seen in Cases 2 and 4, and the secondary sexual characters can remain 

 fully and typically male in the entire absence of the gonads, as is illus- 

 trated by Cases 21 and 22. 



