THE HYPOPHYSIS IN REPTILES 271 



Lumina. As noted by other investigators, the slit-like lumen 

 disappears early from the lateral buds in all reptiles. A very 

 small lumen is present in the pars intermedia of a 21 mm. turtle 

 embryo, though two very young adults also show a lumen in 

 the anterior lobe. A 12 cm. Eutaenia sirtalis has a small lumen 

 in the anterior lobe (fig. 40) while in a 10 cm. Tropidonotus this 

 is continuous with a flattened, slit-like lumen in the pars inter- 

 media. In 12 cm. alligators there is a small lumen extending 

 into the pars intermedia from the caudal part of the anterior 

 lobe, while in a 37 mm. Lacerta viridis the lumen of the anterior 

 lobe is connected with a larger one in the pars intermedia. It 

 appears, therefore, that in turtles and lizards a lumen persists 

 in the pars intermedia for a longer time than that in the an- 

 terior lobe. The contrary seems true for snakes and alligators, 

 the lumen of the anterior lobe persisting longer than that of the 

 pars intermedia. Gaupp ('93) found a lumen in the pars inter- 

 media in a 60 mm. Anguis embryo, but it was not present in 

 older specimens. Bruni ('13) described a lumen in the caudal 

 part of the hypophysis in 44.7 mm. Gongylus. A persistent 

 lumen has already been described in the pars intermedia of adult 

 Sceloporus. 



Although in young embryos mitotic figures are always central 

 in position, there is no glandular ingrowth into the lumen as 

 Herring ('08) found in the cat. It would appear that the lumen 

 in reptiles is not closed off by inward glandular growth. 



CONCLUSIONS 



The epithelial portion of the hypophysis develops as a single 

 anlage in turtles, lizards and snakes and probably in alligators. 



In the development of the evaginations of the hypophysis 

 Rathke's pouch appears first, then the two lateral buds, and 

 finally the anterior bud. 



The lateral buds in turtles give rise to the part termed by 

 Tilney 'pars tuberalis,' and to a thin cortical zone around the 

 middle of the anterior lobe; in alligators to the pars tuberalis 

 and two bands encircling the anterior lobe; in lizards they appear 



