F(ETAL NUTRITION: THE PLACENTA 415 



spongy layer, in which the glandular culs-de-sac have expanded 

 to form large cavities separated by partitions, the mesenteriform 

 lamellae. Gradiially the roof of this layer is also absorbed by 





Fig. 98- — The angioplasmode of the dog at the thirtieth day of pregnancy. 

 (From Duval's " Le Placenta des Carnassiers," Journ de I'Anat. et de la 

 Phye., 1893.) 



ms, mesoblast ; tr, trophoblast ; ae, ectodermio arcades ; d, layer of 

 glandular detritus. 



the trophoblast, and the ectodermal arcades at the tips of the 

 viUi gain a permanent attachment to the mesenteriform lamellae. 

 At the same time, by the further branching and penetration 



