158 



Sex-Reversal in Frogs and Toads 



Right gonad. From behind forwards this consisted of (1) a pyriform 

 testis-portion ; (2) an ovary-portion ; and (3) a Bidder's organ. 



Left gonad. Posteriorly, an anomalous ovary ; and in front of this, a 

 Bidder's organ. 



Vasa efferentia. " Serial sections revealed the lack of a rete testis." 



Miillerian ducts. Right one relatively long and thin, terminating 

 blindly ; left one relatively shorter and also terminating blindly. On 

 section the testis-portion of the right gonad showed the presence of 

 sperms of normal appearance mingled with other cellular elements 

 having variable form and size, " many of which are to be considered as 

 spermatids or spermatocytes in more or less advanced stages of de- 

 generation." The intercanalicular connective-tissue was abundant around 

 the tubules towards the centre of the testis-portion, and between the 

 tubules were numerous cells pigmented yellowish-brown. 



The ovarian tissue of both gonads presented common characters. 

 The smaller oocytes presented a normal structure but the larger ovules 

 exhibited signs of degeneration and contained numerous granules of 

 yellow-brown pigment. 



Since the Miillerian ducts ended blindly, the ova, even if produced, 

 could not be emitted. 



Fig. 33. 



Fig. 34. 



Group B. On inspection both gonads ovo-testes. 



34. Cerruti. (B.) Biifo vulgaris. Adult. Secondary sexual charac- 

 ters not described. 



Right gonad. Posteriorly, a pyriform testis-portion ; anteriorly, an 

 ovary- portion. From the anterior part of the testis-portion "one sees 



