OF THE BEAVER AJSTD OF SOME SQUIRRELS. 



1209 



discharging into a common chamber or cloaca, the aperture of 

 which, closed by a. sphincter muscle, is placed at the base of the 

 thick hairy portion of the tail. In the male, moreover, there 

 is no scrotum, the testes being inguinal in position, that is to say, 

 beneath the integument covering the pubic portion of the pelvis. 

 (Text-%. 59, D.) 



Text-figure 59. 



D. 



A. Anal and genital region of male of Callosohmis prevosti, from below. 



B. The same of Geosciurus capetisis, from the side. 



C. „ ,, ,, female Cynomys Indovicianus. 



D. „ ,, „ male or female Castor fiber. 



a, anus ; sc, scrotum ,: _p, prepuce ; v, vulva ; cl, orifice of cloaca in Castor. 



When the cloaca of the male is opened, four orifices, two 

 median and one on each side, are seen to open into it. The 

 posterior and larger median orifice is the anus, the anterior and 

 smaller median orifice is the common aperture of the penis and 

 the castoriuni glands. The paired orifices, one on each side and 



