SUPPLEMENTARY NOTES ON TWINS IN CATTLE. 



6 7 



tween. In the female (Fig. 13) the germinal epithelium (about 

 140^ in thickness) is in very active proliferation forming several, 

 to many, layers of nuclei. Cords of Pfliiger are definitely indi- 

 cated in the new cortex thus established. The primary albuginea 

 contrasts with that of the male by its more embryonic type. The 

 primary sex cords are not sharply differentiated from the stroma 



Fig. 10. Outlines of cross sections through center of the gonad, (a) of free- 

 martin No. 62, (b) of male twin No. 62, (c) of normal J No. 54C illustrated 

 in Fig. 9. 



of the medulla. The free-martin (Fig. 11) shows the same three 

 layers. The primary albuginea and the medulla do not differ 

 much from those of the female, but the preservation in formalin 

 was not good enough for detailed comparisons on this point. The 

 germinal epithelium is thicker than in the male, but only about one 

 fifth on the average of the thickness of the female. It is, indeed, 

 not as thick as that of a normal female of 3.0 cm. and contrasts 



