THE HYPOPHYSIS IN REPTILES 221 



of investigators and the terms they have employed in describ- 

 ing the various parts of the reptilian hypophysis, together with 

 the species studied, may be of value (p. 222). 



A review of the literature shows that various questions are 

 still unsettled. Regarding the development Rathke's pouch 

 has very generally been thought to form the anlage of the 

 hypophysis, but whether' the notochord takes any part in 

 its formation has not been determined. Gaupp believed the 

 lateral buds to be separate outpouchings. Their ultimate fate 

 has been described by Gaupp in lizards and by Gisi in Sphen- 

 odon. Whether in other reptiles they form a pars termi- 

 nalis, as Gisi thought probable in Sphenodon, or whether the 

 tongue-like process is formed from the anterior lobe (Stendell 

 '14), remains in doubt. Reese stated that lateral buds are 

 absent in alligator embryos, but Tilney observed a tongue-like 

 process in adults. Lateral buds have not been described in 

 snake embryos. In Gongylus, Bruni believes the pars inter- 

 media develops from the tip of Rathke's pouch. A lumen 

 between the pars intermedia and the anterior lobe or in the 

 pars intermedia itself, has been observed in various reptiles 

 (Tilney, Stendell) although its presence has been denied in others 

 (Sterzi). Staderini described the isolated masses derived from 

 the lateral buds in Gongylus as being histologically like the 

 remainder of the hypophysis, although this cannot be confirmed 

 by my material. 



MORPHOGENESIS OF THE HYPOPHYSIS 

 Turtles 



In transverse sections of a 2 mm. Chelydra embryo, there is 

 a thickened hypohyseal plate showing no evagination. A median 

 evagination projecting forward against the brain wall is present 

 in a 2.6 mm. embryo. 



The following description is based on a study of Aromochelys 

 odorata and Chrysemys marginata. Wax reconstructions were 

 made of several of the former, while the latter were studied in 

 section. 



