THE HYPOPHYSIS IN REPTILES 



247 



pars glandularis (anterior lobe), forming a thick layer over the 

 anterior end of the latter. In the turtles and alligators studied, 

 the pars intermedia is not continuous anteriorly with the pars 

 tuberalis as Gisi described for Testudo graeca. In snakes only 

 does the anterior lobe come into contact with, the floor of the 

 brain (fig. 46). 



The dorsal tip of Rathke's pouch in 10 mm. turtles proliferates, 

 and in 14 mm. embryos is somewhat constricted from the re- 

 mainder of the pouch (fig. 4). This dorsal tip, not the entire 



Figs. 45 to 4S Median sagittal sections of brains of reptiles showing infun- 

 dibulurn and hypophysis. 45, turtle X10; 46, snake X 13; 47, lizard X 35; 48, 

 alligator X 13 (W. U. C. 202, 186, 190, 212). Fine stipple, anterior lobe; coarse 

 stipple, parts derived from lateral buds; lined, pars intermedia; black, brain 

 and infundibulum. b, basis cranii; c, anastomosing branch of carotids. 



pouch, gives rise to the pars intermedia (Tilney's pars infundibu- 

 laris, Sterzi's chromophobic). A similar development was de- 

 scribed by Bruni ('14) in Gongylus and by the writer ('15) in 

 Acanthias. Bruni states: "Dei tre lobi il medio, destinato a 

 mettersi in rapporto col processo infundibulare . . . . , 

 origina come un diverticolo dalla parte piu distale della parete 

 rostrale della tasca di Rathke ' (p. 186). A dis- 

 tinct constriction of Rathke's pouch where it joins the anterior 

 bud is evident in young turtle embryos. In 9 mm. embryos 

 the constriction is less evident than in younger, and in 17 mm. 

 embryos it is no longer apparent. Woerdemann ('14) noted 



