108 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 



Gemmill : The ostium and the anterior portions of the duct are from 

 a peritoneal evagination. The remainder of the duct is developed partly 

 from the Wolffian duct. No mention is made of a cephalic displacement 

 of the ostial opening. 



Hall : The ostium and the anterior end of the duct are formed from 

 the peritoneal epithelium. This fundament had originally the shape of 

 two separate evaginations. Only a small portion of the growing duct 

 takes cells from the "Wolffian duct. The remaining portion grows back 

 independent of Wolffian duct and peritoneum. A cephalic migration of 

 the ostial opening is brought about by the closure, from behind forward, 

 of a thickened groove of peritoneal epithelium. 



Gymnopliiona. 



Semon : The ostium and anterior end of the duct are formed from a 

 peritoneal evagination, the remainder of the duct from cells of the 

 oviducal welt. 



Anura. 



Hoffmann : The anterior portion of the Wolffian duct is converted 

 bodily into the Mullerian duct. It separates from the pronephros and 

 fuses \vith the thickened peritoneal epithelium to form the ostium. After 

 dividing obliquely at the anterior end of the mesonephros, the anterior 

 section grows back, probably with the aid of cells of the oviducal welt, to 

 form the remainder of tlie Mtillerian duct, the posterior section remain- 

 ing as the Wolffian duct. A cephalic migration of the ostial opening 

 takes place along a thickened groove of the peritoneal epithelium. 



MacBride : The ostium and anterior end of the duct are formed from 

 a peritoneal evagination, the remainder of the duct, at first in the form 

 of disco-ntinuous pieces, from cells of the oviducal welt. There exists a 

 cephalic migration of the ostial opening similar to that described by 

 Hoffmann. 



Gemmill : The ostium is from a peritoneal evagination, and the entire 

 duct is formed by a prolongation of the free end of this evagination. 

 There is a cephalic displacement of the ostial opening as described by 

 Hoffmann and MacBride. 



Hall : My description is in agreement with that of Gemmill with the 

 exception that evidences were seen of three original evaginations to form 

 the ostial fundament. 



