254 E. A. BATJMGARTNER 



bered, however, that the different drawings were not made at 

 the same magnification. 



Bruni found that in reptiles, birds, and mammals the axis of 

 the hypophysis and hypophyseal stalk shifts from a horizontal 

 to a perpendicular plane and then back again to a near-hori- 

 zontal. Figure 51, of a series of alligator hypophyses, shows 

 the axis of the stalk of the intermediate stage, anterior to that 

 of either younger or older stages. It would seem that the length 



Fig. 50 Drawings of median sagittal sections of the hypophyses of alligator 

 embryos. A, 12 mm. (R. C. 27); B, 22 mm.; C, 120 mm. (W. U. C 176, 178;) 

 x-y, base line. 



of the radius of the arc would affect the amount of shifting shown. 

 An interesting comparison between the two methods is made 

 possible by adding the outline of the hypophysis to the method 

 described by Bruni. The latter shows that in young alligator 

 embryos 12 and 22 mm. in length there is a marked forward 

 migration of the entire structure. In the later embryo, 120 

 mm. there is a dorsal shifting from the position in the inter- 

 mediate stage (22 mm.). By the first method (fig. 50) the 

 earlier shifting was dorsal ward and the latter forward. 



