150 Sex-Reversal in Frogs and Toads 



Left gonad. An ovo-testis similar in appearance to the right save 

 that there was no pigmented lobe at the anterior pole. 



Vasa efferentia on both sides as those of the normal male. 



Seminal vesicles small and spindle-shaped. 



Miillerian ducts well-developed. 



On section, the greater part of each gonad had the structure of 

 normal testis, but ova were found in considerable numbers lying between 

 the seminal tubules. The great majority of these ova were immature 

 and showed signs of degenerative changes. The pigmented bands were 

 composed of densely packed granules of pigment and hyperplastic 

 connective-tissue. The anterior lobe of the right gonad consisted partly 

 of normal testicular tissue and partly of ova in a state of extreme de- 

 generation. The ovarian tissues were not discrete from the spermatic 

 and were pathologicab 



12. Crew. (3.) R. esculenta. Adult. Killed November. Secondary 

 sexual characters typically male. 



Right gonad. An ovo-testis having the appearance of an irregularly 

 shaped testis with bands of dense black pigmented material running in 

 deep grooves along its twisted outer border. 



Left gonad. An ovo-testis, consisting of six lobes, five of which were 

 ovarian, and the other, testicular in appearance. The testicular lobule 

 was placed centrally and medially in relation to the others. 



Vasa efferentia, of the ordinary male pattern on the right : on the 

 left four in number and connected with both ovarian and spermatic lobes 

 of the gonad. 



Seminal vesicles present but small and spindle-shaped. 



Miillerian ducts well-developed. 



On section, all those parts of the right gonad not including pigment 

 had the structure of normal testis. The pigmented nodules consisted of 

 densely packed polygonal masses of pigment granules and hyperplastic 

 connective-tissue. No ova were found amid this pigment, but near to 

 this two ova were seen lying between the seminal tubules of the sper- 

 matic tissue. The pigment had the appearance of following the lines 

 of the intertubular connective-tissue. The left gonad consisted of two 

 distinct portions. The five pigmented lobes were composed of patho- 

 logical ovarian tissue in which degenerate ova were included among 

 dense polygonal masses of pigment and hyperplastic connective-tissue. 

 The spermatic lobe, discrete from the rest, was entirely testicular in 

 structure. The renal vessels of both sides lay in deep pigmented 

 channels upon the surface of the kidneys and the pigment was identical 

 microscopically with that of the ovary-portions of the ovo-testes. 



