366 



THE RABBIT. 



in Fig. 148. The several divisions of the brain are cleai*ly re- 

 cognisable, as are also the nose, and the eyes and ears. On the 



c/x 



EK 



FlG. 148. A Rabbit Embryo and foetal appendages at the end of the twelfth 

 day. The embryo is represented in surface view from the right side : the 

 yolk-sac and foetal membranes are shown in median longitudinal, or sagittal 

 section. The hind-limb and part of the tail have been removed to allow 

 the yolk-stalk and allantoic stalk to be fully seen. In part after Van 

 iteneden and Julin. x 8. 



AX, amnionic cavity, between the inner or true amnion and the embryo. C, CX, 

 extra-embryonic part of the coelom or body-cavity. E, epiblast. E', ectoplacenta, or 

 thickened part of the epiblast, from which the placenta is formed. EK, epiblastic 

 villi. H, hypoblast. M, mesoblast. SI, sinus terminalis. TA, cavity of allantois. YS, 

 cavity of yolk-sac or blastodermic vesicle. 



sides of the head and neck the visceral arches and clefts are 

 well seen ; and both fore and hind limbs have attained consider- 

 able size, and show indications of division into their several 

 segments. 



The twelfth-day rabbit embryo corresponds closely in form 

 and in structure to a chick embryo of the middle of the sixth 

 day, and is of very nearly the same actual size. The chief points 

 of difference between the two are the much smaller size of the 



