278 



Dr. M. Watson. 



The calibre of the urogenital canal equals that of the vagina, the 

 separation of the two organs being marked by the orifice of the 

 urethra and by the fringe-like fold of mucous membrane just de- 

 scribed. The mucous membrane of the urogenital canal does not 

 differ in character from that of the vagina. 



Having now described the female organs, I pass to the consideration 

 of the 



Ovum. 



On opening the gravid uterine horn by means of an incision carried 

 along its anterior or convex margin, a single foetus was observed to 

 occupy the greater part of the cavity. The foetus itself, covered only 

 by an epitrichial membrane, was at once in part exposed, from which 

 it was evident that before coming into my hands the foetal membranes 

 had been ruptured. These membranes, although ruptured, where they 

 lay in contact with the posterior extremity of the foetus so that the 

 latter was in contact with the wall of the uterus, retained their relation 

 with the anterior moiety of the embryo ; and I was thus enabled to 

 make out the arrangement of both the chorion and allantois. With 

 regard to that of the amnion there still remains some doubt, but to that 

 I shall refer presently. The foetus, curled upon itself, lay with its 

 head directed towards the free extremity of the uterine horn, and close 

 to the opening of the Fallopian tube, being separated from the latter 

 merely by the intervention of the foetal membranes which covered it. 

 The left anterior extremity was closely applied to the side of the 

 chest, whilst that of the right side was strongly flexed at the elbow- 

 joint, so that the palmar surface of the hand rested against the side of 

 the head. The posterior extremity of the foetus touched the septum 

 uteri, and the hind legs, fully extended, stretched backwards towards 

 the body of the organ. The tail, strongly flexed, occupied the interval 

 between the hind legs. The dorsal surface of the foetus was accu- 

 rately adapted to the anterior or convex surface of the uterine horn, 

 whilst the ventral surface was directed backwards towards the posterior 

 or concave margin of the latter. 



The position of the foetus of Procyon in utero appears to be some- 

 what unusual. In the majority of mammals, according to Milne- 

 Edwards,* the head of the foetus usually presents at the os uteri m 

 whilst in Procyon the posterior extremity of the embryo occupied that 

 position. 



The foetus was encircled by an annular or zonary placenta which 

 corresponded to the middle third of the uterine horn, and measured 



* " Le9ons sur la Physiologie," vol. ix, p. 591. 



f Turner describes the foetus as occupying this position in utero in the seal, 

 " Trans. Koy. Soc. Edin.," vol. xxvii, p. 278 ; sloth, ibid., p. 75 j and lemur, " Phil. 

 Trans.," vol. 166, p. 574. 



