234 

 for it. 



EMBRYOLOGY. 



But in the interest of a more precise definition it is advisable 

 9 to use the name 



0' 



U 



Fig. 135a. Uterus of a Cow laid open, in the middle of the period of 



gestation. From BALFOCR, after COLIN. 

 V, Vagina ; U, uterus ; Ch, chorion ; C\ cotyledons of the uterus ; C 2 , foetal 



cotyledons. 



only in the re- 

 stricted sense 

 in which it has 

 been employed 

 in this chapter, 

 and in other 

 cases to speak 

 of a villous 

 membrane or 

 chorion only. 

 The forma- 

 tion of the pla- 

 centa presents 

 in its details 

 important mo- 

 difications. 



The Rumi- 

 nants, in which 

 the blastoder- 



mic vesicle is drawn out into two tips, as in the Pig, present a 



special type 



(fig.!35a). On 



their chorion 



(CK) have been 



developed very 



many small 



fetal placentae 



( 2 ),whichhere 



are also called 



cotyledons. The 



number of the 



latter is ex- 

 ceedingly vari- 

 able in the 



different spe- 

 cies, from sixty 



to one hundred 



in the Sheep 



and Cow, and only from five to six in the Doe. They are united with 



Fig. 135b. Cotyledon of a Cow, the foetal and maternal parts half 

 detached from each other. After COLIN, from BALFOCR. 



M, Uterus ; C", maternal part of the cotyledon (placenta uterica) ; 

 Ch, chorion of the embryo ; C*, foetal part of the cotyledon 

 (chorion frondosum or p'.acenta foetalis). 



