UROGENITAL SYSTEM 109 



about 42 mm. in length, while the convergence of the 

 horns to the uteral body was fairly intermediate in shape 

 between Homodontomys and Teonoma. 



In Teonoma the right uteral horn measured 40 mm., 

 and the left 43. Their convergence was broader and defi- 

 nitely U-shaped. 



The vaginal opening is situated caudad to the clitoris 

 and in normal position it is partially covered, and protected, 

 by the latter. In no specimens examined was the vulva 

 closed by an epithelial membrane as Miller (1895) found 

 to be the usual condition during sexual inactivity of Pero- 

 myscus and some other rodents. Donaldson (1924, p. 

 153), however, states that "in the immature female (white 

 rat) the vagina is closed by a membrane. This usually 

 breaks down just before the first oestrous." That such 

 may possibly be the case in Neotoma as well can not be 

 denied. 



