450 



HOMER WHEELON 



either stimufating or inhibiting factors have acted upon the sexually 

 neutral or indifferent somatoplasm. 



Observations on the Free-Martin. This view is substantiated by the 

 observations of Lillie on the free-martin (Figs. 10, 11, 12). As a rule the 



Fig. 10. Reproductive organs of fertile free-martin 23.3 em. long. X 4/3. The 

 chorion of the twins was single with a narrow connection between the two halves. 

 Presumably no vascular anastomosis. The male was 26.5 cm. long, nearly 80 per cent 

 heavier than the female, and its skin was unpigmented, whereas the female was darkly 

 pigmented. 1, ovary; 2, left horn of uterus; 3, round ligament; 4, vagina; 5, clitoris; 

 6, neck of allantois. (Lillie, 1917, Fig. 8, p. 430.) 



female of two-sexed twins of cattle is sterile. The internal reproductive or- 

 gans in these sterile females are usually predominatingly male in character; 

 the external organs, female in type (Fig. 11). The Miillerian ducts are 

 usually diminished or absent; the Wolffian ducts are often developed into 

 quite typical vasa deferent ia and the gubernaculum develops as in the male. 

 The gonad is testis-like in form and structure by reason of the complete 



