230 E. A. BAUMGARTNER 



made to show the relations of the various parts. The first 

 drawing shows the oval end (fig. 9) lying ventral to the floor of 

 the brain. A second drawing of a section further caudally 

 shows the anterior lobe almost surrounded by the proximal 

 parts of the lateral lobes. A thin layer of the distal portions of 

 the lateral lobes is applied to the floor of the brain (fig. 10). 

 Figure 11, almost 2 mm. from the anterior end, shows the anterior 

 lobe completely surrounded, with the distal portion lying against 

 the floor of the brain. The anterior lobe of the hypophysis, 

 between the two points of attachment with the brain, is almost 

 rectangular and is surrounded by the lateral lobes (fig. 12). 

 The last drawing of the series (fig. 13) shows the rectangular 

 anterior lobe partially surrounded by the lateral lobes, and lying 

 against the ventral surface of the pars intermedia and the 

 cerebral-carotid arteries on either side. The pars intermedia, 

 which in embryos forms a wide mass, closely applied to the 

 ventral surface of the infundibulum and extending between its 

 various branches, is in contact with the upper surface of the 

 anterior lobe. 



Development in lizards 



Young Lacerta embryos of 1.6 to 3 mm. in length do not show 

 the relation between the epithelial linings of the pharynx and 

 the head cavities described by Salvi ('12, '02). No distinct 

 hypophyseal angle is present in a 2.8 mm. embryo. 



In a 3 mm. embryo (Lacerta agilis) a distinct hypophyseal 

 angle of thickened epithelium is present. In a reconstruction 

 of this part, the hypophysis is a wide ridge lying close to the wall 

 of the brain. On either side, near the edge of the ridge, the 

 cerebral carotids lie close to the epithelium. Dorsal to the 

 median part is a large venous channel. Caudal to the ridge a 

 prominent angle of epithelium projects dorsal ward beyond the 

 hypophyseal angle. 



A wax reconstruction of a 5.0 mm. embryo shows a slight 

 median evagination from the oral roof — Rathke's pouch (fig. 63). 

 The caudal side descends sharply while the cranial side slopes 

 gradually and is continuous with an anterior thickened epi- 



