THE HYPOPHYSIS IN REPTILES 211 



LITERATURE 



Embryology 



In 1838 Rathke described a small outpouching from the mouth 

 in the viper, lizard and chick and stated that it later developed 

 into the pituitary body by the closing off of the hypophyseal 

 stalk and the formation of a closed vesicle. Later ('39) he 

 noted in the viper, its close relation to the brain, the numerous 

 blood vessels — particularly the veins in the older embryos — and 

 the carotids on either side supplying vessels to the body. The 

 adverse opinions of his contemporaries led him to doubt his 

 earlier observations, and in further study ('61) he concluded 

 that the outpouching from the mouth did not develop into the 

 hypophysis. 



Sasse ('86), in a dissertation on the development and theories 

 of the function of the hypophysis, figured the hypophysis in very 

 young Tropidonotus and Lacerta and noted the thickening of 

 the hypophyseal outpouching. 



Orr ('87), in describing a median connection between the pre- 

 mandibular somites, 'the coelenteric zone,' observed the inti- 

 mate relation between this zone, the notochord and the hy- 

 pophysis. 



Ostroumoff ('88) briefly stated that the hypophysis of the 

 lizard is of entodermal origin. Hoffmann ('86) also believed 

 that the hypophysis, in Tropidonotus and Lacerta arises from 

 the entoderm, but realized that this question could not easily 

 be solved. His figures show prominent anterior and posterior 

 portions in older embryos. 



In 1890 Jagerskiold described, in some detail, the hypophysis 

 of Tropidonotus natrix. In embiyos with heads 4.5 mm. in 

 length, the hypophyseal stalk is partly constricted. A median 

 sagittal section of the hypophysis is crescent-shaped, the an- 

 terior and posterior horns extending toward the brain, though 

 they were not in contact with it. Measurements of the various 

 diameters of the hypophysis and hypophyseal stalk of the em- 

 bryos are given. 



Oppel ('90), studying the head somites, noted the hypophyseal 

 evagination in his 'Series II' which has 55 somites. In Anguis 



