Pt. otk: 
HUBRECHT. 
iS EEUh twaanald 
a “AT NG 
Two stages in the development of the connective stalk 
Fig. 156 and 157. 
and the umbilical vesicle of Hylobates concolor and H. Rafflesii (after Selenka, 
00). The proliferating network on the umbilical vesicle is strongly developed 
and of haematopoietic significance. Vascularized trophoblastic villi are visible 
in Fig. 157. cs connective stalk, v placentary trophoblastic villi, wz vascular 
network on the umbilical vesicle, @// allantoic tube, 2c neurenteric canal. — 
Fig. 158. Section through the stalked discoid placenta of Cavia (after Strahl, °O6). 
