EMBEYO OF KANOAKOO. 



827 



walls of the gravid uterus were obviously dilated, and its parietes varied 

 in thickness from one to two lines, being in the unimpregnated state 

 about half a line ; but this increase was not in the muscular coat, but 

 in the lining membrane, which was thrown into irregular folds and 

 wrinkles. There was, however, not the slightest trace of any vascular 

 connexion between the uterus and the ovum neither placenta nor villi, 

 nor any determination of vessels to a given point on either of the 

 opposed surfaces of the chorion or uterus : on the contrary, the external 

 membrane of the ovum (chorion) exhibited not the slightest trace of 

 vascularity, even under the 



microscope, and seemed in Fi g- 417. 



every respect to resemble 

 the membrana putaminis 

 that lines the egg-shell. 



(2443.) The body of the 

 foetus itself was immedi- 

 ately enclosed in a trans- 

 parent membrane (>), the 

 amnios. 



(2444.) Between the 

 chorion (a) and the amnios 

 (6) was an extensive vas- 

 cular membrane (c, dd,ee): 

 its figure seemed to have 

 been that of a cone, of 

 which the apex was at the 

 umbilicus of the foetus. 



(2445.) Three vessels 



COUld be distinguished dl- 



verging from the umbilical 



cord, and ramifying over it. Two of these trunks contained coagulated 

 blood ; while the third was smaller, empty, and evidently the arterial 

 trunk. No trace of any other membrane could be seen' extending from 

 the foetus, besides the three above mentioned the chorion (a), the 

 amnios (6), and the interposed vascular membrane, the nature of which 

 becomes the next subject of inquiry. 



(2446.) On tracing the three vessels above alluded to as ramifying 

 over the vascular membrane through the umbilicus into the abdomen, 

 the two larger ones, filled with coagulated blood, were found to unite, 

 and, after being joined by the mesenteric vein, penetrated the liver : 

 these, consequently, were the representatives of the omphalo -mesenteric 

 or vitelline vein of the embryo Bird ( 2136). The third vessel passed 

 between the convolutions of the small intestine along the mesentery to 

 the abdominal aorta, corresponding to an omphalo -mesenteric or vitelline 

 artery. The membrane, therefore, upon which they ramified answers 



Embryo of Kangaroo. 



