1884.] 



OF TETRACEROS QUADRICORNTS. 



Fig. 3. 



One extremity of chorion of Tetraceros qtutdncornis. 

 al, allantoic diverticulum ■ co., cotyledon; r., its raised rim ; di., diffuse vas- 

 cular ridges ; b., crown of blood-vessel, shown by greater prominence of 

 ridges ; v., small patch of cotyledonary villi. 



Fig. 4. 



V-yU.ql. 



Maternal cotyledon of Tetraceros, 

 a. <il., mouths of uterine glands. 



