226 E. A. BAUMGARTNER 



lobes have increased in their cranio-caudal diameter, and their 

 attachment to the anterior lobe has grown cranialward. Their 

 free ends extend distinctly upward and almost at right angles 

 to the median lobe. 



A 9.2 mm. embryo has a longer hypophysis, the increase in 

 length being marked in the median portion, or Rathke's pouch 

 (fig. 3). The dorso-ventral diameter, especially that of the 

 anterior lobe, is greater. The stalk is elongated and its lumen 

 is just perceptible, except at its attachment to the hypophysis, 

 where a distinct dilatation is found. Several small glandular 

 outgrowths are present, the one near the notochordal tip having 

 a small lumen. The basi-sphenoid cartilage presses against the 

 caudo-ventral wall of the hypophysis. In a 9.5 mm. Chrysemys 

 embryo, the lateral lobes are attached to the ventro-lateral side 

 of the anterior lobe. 



The hypophyseal stalk in a 14.5 mm. embryo is short, solid 

 and extends caudalward and upward, showing evidence of degen- 

 eration near its attachment to the hypophysis (fig. 4) . The 

 anterior lobe has many glandular outgrowths from all its sur- 

 faces and the central lumen has almost entirely disappeared. 

 The upper wall of the apex of Rathke's pouch has grown for- 

 ward, giving the appearance of a new growth lying just below 

 the infundibulum. A constricted neck connects this with the 

 remainder of Rathke's pouch, which now resembles the anterior 

 lobe in structure. The lumen of the apical enlargement is con- 

 tinuous with that of the central portion of the anterior lobe. 



In a 17 mm. Aromochelys embryo, the long axis of the hy- 

 pophysis extends cranio-caudally and almost in a horizontal 

 plane (fig. 62). Many irregular, cord-like growths from the sur- 

 face of the hypophysis, have made their appearance. The flat- 

 tened apical enlargement of Rathke's pouch, which in previous 

 (8 mm.) stages was somewhat constricted from the remainder, 

 lies dorsal to the caudal end of the pouch. Cords extend later- 

 ally, anteriorly and caudally from this enlargement. The main 

 part has a small lumen. Ventral to this portion of Rathke's 

 pouch, and cranial to the constriction, many irregular cell cords 

 extend caudalward. A ventrally-lying cyst-like mass contains 



