236 



E. A. BAUMGARTNER 



In a 22 mm. embryo, it is evident that the position of the 

 hypophysis has shifted because of the straightening out of the 

 cranial folds. The whole organ has elongated. The tip of the 

 notochord lies caudo-ventral to Rathke's pouch (fig. 24). There 



Figs/ 22 to 26 Median sagittal sections of alligator embryos. 22, about 12 

 mm. (R. C, F. 16) X 50; 23, 14 mm. X 40; 24, 22 mm. X 40; 25, 28 mm. X 30; 26, 

 120 mm. X 15 (W. U. C. 175, 176, 177, 178). A, anterior bud or lobe; /, pars 

 intermedia; R, Rathke's pouch; b, basis cranii;^, brain wall ; Ca, anastomosing 

 branch of the carotids; c, cartilage; i, infundibulum; M, epithelium of mouth; N : 

 notochord, St, stalk. 



are many outgrowths from the dorsal and anterior walls of the 

 anterior lobe and a few from the floor. Of the latter a very 

 prominent one extends caudally, ending in front of the anasto- 

 mosing artery of the cerebral carotids. The hypophyseal stalk 



