THE HYPOPHYSIS IN REPTILES 



239 



intermedia. A small cystie tubule is often found on the ventral 

 side of the anterior lobe caudal to the lateral lobes (fig. 34). 

 Near its caudal end this tubule becomes solid. Judging from its 

 position and from the fact that the hypophyseal stalk is present 

 in very late embryos this elongated tube is probably the remnant 

 of it. 



In a specimen about 22 cm. long, a ventral stalk-like tubule 

 extends caudally, then ventrally and ends blindly in a notch in 

 the floor of the cranium. A strand of connective tissue continues 

 from the blind end of the tubule through a small canal in the 



Figs. 30 to 34 Transverse sections of the hypophysis and infundibulum of an 

 adult alligator 47 cm. long. X 10 (W. U. C. 213). Stipples and lines as in figure 

 27. Ca, carotid arteries; s, remnant of stalk. 



floor of the cranium and turning to the right ends under a granu- 

 lar epithelium lining a cavity in the cranial floor. This stalk, 

 about 75 micra in length, is very much shorter than the hypo- 

 physeal stalk in a 12 cm. embryo. 



Development in snakes 



Snake embryos (Vipera verus) 3 mm. long have a median 

 evagination resembling in general shape and position Rathke's 

 pouch in other reptiles. Embryos 5 mm. long have a very 

 much longer median pouch and at either side definite lateral 

 ridges (fig. 66). The furrow separating these ridges from the 

 median pouch never becomes as prominent as in turtle and 

 lizard embryos. A median sagittal section of a 7 mm. Tro- 



