1022 



EMBRYOLOGY. 



lated hippomanes, and T have been able to make the following observations, 

 through having met with a large number on a foetus : — 



" Besides the free hippomanes found floating in the allantoid fluid, there were 

 remarked, on tlie outer wall of the sac, a great number of small tear-shaped bodies 

 of variable size, adhering by a pedicle which was more or less narrow as the mass 

 was more developed. Their colour was the same as that of the principal hippo- 

 manes, and if pressed between the fingers, the brown matter contained in a thin- 



Fi?. 557. 



FCETUS ('F THE JIARE. WITH ITS ENVl'LOPES. 



^, Chorion; C, amnion removed from the allantoid cn-ity, and opened to expose the foetus; D, 

 infundibulum of the urachus; 5, allantoid portion of the umbilical cord; b, point of the external 

 surface of the chorion, destitute of placental villi, and corresponding to the part where the three 

 pediculated hippomanes are attached. 



walled sac escaped by the pedicle, and spread itself over the external surface of 

 the chorion. There the villo^^ities of the placenta were absent at the margin of 

 the opening, which was surrounded by a whitish areola (Fig. 557, b). 



*' Might it not be admitted, from this disposition, that the hippomanes is 

 developed between the placenta and the uterus, and is carried inward, by pushing 

 before it the chorion and layer of the allantois covering it, until, on reaching the 



