OBSTETRIC A L PHYSIOL OG Y. 



in contact. The middle of its inner surface is united to the amnion 

 and the allantois by loose gelatinous connective tissue, so laminated 

 that it might be mistaken for different layers of membrane. It is only 

 covered by the allantois in the portions corresponding to the cornua, 

 which are longer than those of the uterus. It offers numerous small red 

 masses, studded at variable distances from each other on the surface 

 next the uterus, and w^hich effect a very important connection between 

 the latter and the chorion. These are the placentida, to which 

 we shall allude presently. 



In the Sheep and Goat, when there are two young creatures, the 

 cornua of the chorion are joined, so as to look, externally, like one 

 sac. 



Fig. 4S. 



F(ETUS A.ND 1\KTAL MeMBR.\NES OF THE CaT. 



a, a, Chorion ; h. Zonular Placenta ; (/, Umbilical Vesicle, with its Expansions, 

 f, between Amnion and Placenta, and g, its Pedicle of attachment to a loop 

 of small intestine ; li, Allantois ; Tc, Foetus. 



Pig. 

 In the Pig there are no cornua, but the whole appears as an elongated 

 sac, whose two extremities, much exceeding those of the embryos, are 

 i-elated to the envelopes of the contained progeny. Its internal face is 

 similar to that of Euminants ; on its external face are groups of 

 numerous small papillae ; so that placentation in this animal is dis- 

 seminated, though here and there, between the innumerable groups of 

 papilliB, are bare spots merely covered with epithelium, and there are 

 no papillae at its extremities. 



Bitch and Cat. 

 In the Bitch and Cat, the arrangement of the chorion is similar to 

 that of the Pig ; it has no cornua, its extremities are obtuse, and its 



