898 EMBRYOLOGY. 



presence of the hippomanes in the allantoid sac. Nothing in its appearance 

 indicates that it may be formed at the expense of the liquid contained in this 

 membrane. Sometimes pediculated hippomanes are found, and these may 

 assist in explaining the formation of the free hippomanes. Bourgelat speaks 

 in his ' Anatomic ' of pediculated hippomanes, and I have been able to make 

 the following observations, through having met with a large number on a 

 fcetus : 



Fi ? . 425. 



F(ETUS OF THE MARE WITH ITS ENVELOPES. 



A, Chorion ; c, Amnion removed from the allantoid cavity, and opened to expose the 

 foetus; D, Infundibulum of the urachus; B, Allantoid portion of the umbilical 

 cord. 6, Point of the external surface of the chorion, destitute of placental 

 villi, and corresponding tc the part where the three pediculated hippomanes are 

 attached. 



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

 were remarked, on the 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 



