THE HYPOPHYSIS IN REPTILES 



253 



zontal plane. The dorsal tip of Rathke's pouch migrates dorsal- 

 ward and caudal ward in lizards and in turtles between the 4.6 

 and 6.4 mm. stage, and dorsalward and forward in alligators 

 (fig. 50). The shifting of the axis of the hypophysis as shown in 

 figures 49 and 50 is forward and dorsalward as was observed in 

 Acanthias (Baumgartner '14). 



Bruni ('14) approached the question of the shifting of the 

 stalk and hypophysis from another angle. The writer, for the 



\ D 



Fig. 49 Drawings of median sagittal sections of the hypophyses of lizard 

 embryos (M. U. E. C. 566, 565, 576, 564, 563). A, 3 mm. ; B, 5 mm. ; C, 9 mm. : D, 

 11.6 mm.; E, 15 mm. (length of coil); x-y, base line. 



sake of comparison, made a series of drawings of alligator embryos 

 by Bruni's method (fig. 51). Taking the point of attachment 

 of the stalk to the pharyngeal roof as the center of a circle, an 

 arc is drawn from a caudal point in the pharyngeal roof to an 

 anterior one. Using the center of the circle and the arc as guide 

 lines, and making the distance between the anterior ends of the 

 pharynx at the arc equal to that at the posterior ends, drawings 

 of different embryos were superimposed. Outlines of the hy- 

 pophyses are also included in the figure. It is to be remem- 



