CHAPTER VII 



UROGENITAL SYSTEM 



Kidneys. In all specimens dissected the right kidney- 

 was always situated farther craniad than the left, although 

 the amount of difference in their precise positions varied 

 individually. There is also great individual variation in 

 the size of the kidneys, for in two instances in each subgenus 

 they measured: Homodontomys, 14 by 10 and 18 by 11 mm.; 

 Neotoma, 19 by 14 and 20 by 11 mm.; Teonoma, 24 by 13 

 and 25 by 14 mm. From the medial side of the kidneys 

 extend the ureters, passing caudad to the body of the urethra 

 and then ventrad to their junction with the base of the 

 bladder, upon either side. The neck of the bladder is some 

 12 mm. in length, and the urethral orifice in the male is 

 near the termination of the glans penis. In the female it 

 is upon the tip of the clitoris.^ 



MALE ORGANS 



It happens that the generative organs of the males of 

 the available specimens of Homodontomys, taken during 

 August and December, and of Teonoma secured during 

 August, are in a state of sexual quiescence, while those of 

 Neotoma alhigula, secured the middle of March, are highly 

 active. The difference indicated in the shape of the glans 

 penis is undoubtedly characteristic, at least for everything 



1 This term is employed only tentatively, for so far as the author is 

 aware, the homology of this portion of the anatomy of rodents has never 

 been established. It remains for future investigation to show whether 

 the true clitoris has disappeared entirely and what is now termed the cli- 

 toris is merely an eminence raised about the external opening of the urethra, 

 or whether this eminence constitutes the true clitoris, with some change of 

 relation and function. 



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