244 E. A. BAUMGARTNER 



In a reconstruction of the hypophysis of a very young turtle 

 there are indications that furrows separating the lateral buds 

 from Rathke's pouch begin on the cranial side. Furrows first 

 appear at the same place in the separation of the inferior lobes 

 from Rathke's pouch in Squalus. (Baumgartner '15). 



In the later development of the lateral buds in turtles, the tips 

 grow forward and form distinct distal portions. In 28 mm. 

 embryos these have approached each other across the dorsal 

 side of the anterior lobe, and in adults, form a thin layer closely 

 applied to the floor of the brain. Gisi ('07) believed the same 

 thing occurs in Sphenodon and said: " Wahrscheinlich ist diese 

 Pars terminalis der Hypophyse das Endproduckt der seiten 

 Knospen an den fruheren Embryonalstadien." The develop- 

 ment from the lateral buds of the tongue-like process extending 

 below the brain is similar to that observed by Herring ('08) 

 and carefully described as the pars tuberalis in mammals and 

 birds by Tilney ('13). Joris ('07) undoubtedly saw the same 

 structures as isolated masses near the brain floor in mammals. 2 



The developing proximal portions of the lateral buds surround 

 the anterior lobe, thus forming a thin cortical layer about the 

 middle of this lobe. Gisi did not note this in Sphenodon nor 

 did Tilney describe it in mammals. Miller's ('16) description 

 of a somewhat similar layer in the pig indicates that it may have 

 been overlooked. 



The development of the hypophysis in alligators is similar to 

 that in turtles. Although Reese ('10) did not find lateral lobes, 

 a wax reconstruction of the alligator hypophysis shows them to 

 be present (fig. 68). During development they extend anteri- 

 orly and dorsally. In an adult specimen 47.5 cm. long the 

 distal portions of the lateral buds are not continuous across 

 the median line as in adult turtles, while in an adult 150 cm. in 

 length the distal portions are fused and form a single tongue- 

 like pars tuberalis. It would seem, therefore, that there is some 



- Woerdemann ('14) has given a full review of the literature on the various 

 portions of the embryonic and adult hypophysis. This author saw, in the 'lobus 

 chiasmaticus' and 'lobus praemammillaris' of Staderini ('OS and '09) and also 

 in the 'lobule de la tige' of Joris ('07), a structure homologous with Tilney's ('13) 

 pars tuberalis. With this view I am in agreement. 



