152 Sex-Reversal in Frogs mid Toads 



therein of polygonal masses of pigment and broken down granular 

 material. The left gonad was mainly spermatic in structure but the 

 pigmented parts consisted of masses of pigment, hyperplastic connective- 

 tissue, and a few very degenerate ova. There was ciliated epithelium 

 upon the peritoneum. 



Group C. Those cases in which, on inspection, one gonad was an ovo- 

 testis and the other a testis. 



Sub-group 1. The testis was abnormal in appearance. 



15. Ognew. R. temporaria. Adult. Secondary sexual characters 

 typically male. 



Right gonad. An exceptionally large testis. 



Left gonad. An ovo-testis with a small ovarian portion placed 

 laterally. 



Seminal vesicles were present. 



Miillerian ducts. Right one moderately, left one well-developed. 



No sections were made. 



16. Cole. R. temporaria. Young and apparently immature. Killed 

 during the summer. Secondary sexual characters typically male. 



Right gonad. A testis somewhat enlarged and non-pigmented. 



Left gonad. An ovo-testis with a larger densely pigmented ovary- 

 portion and smaller non-pigmented papilliform testis-portions at its 

 poles. 



Vasa efferentia typically male on the right : on the left, only two 

 but " the divisions of the renal artery to the ovo-testis might well have 

 been mistaken for efferent canals." 



Seminal vesicles not present. 



Miillerian ducts. That of the right side was rudimentary and not 

 convoluted, but had a distinct and densely pigmented uterine segment. 

 That of the left side was pigmented, convoluted, and moderately well- 

 developed, although its uterine segment was non-pigmented. 



On section, the right gonad was a normal testis and with the excep- 

 tion of one small spherical patch and two or three problematical granular 

 bodies, similar to those found in the opposite ovo-testis, pigment was 

 entirely absent. One ovum at " a stage of development corresponding 

 to that found in female frogs of between one and two summers " was 

 found near the surface close to the junction of the anterior and middle 

 thirds of the gonad, and the neighbouring portions of the testis were 

 less conspicuous than the remainder of the gland and contained the 

 most immature spermatozoa. 



