io6 Journal of Comparative Neurology. 



JRig. J. Transverse section through the hippocampal commissure of 

 Eutsenia to show the dorsal projection of the roof of the aula which coTcrs it at 

 this point. 



Fig. 4. Adjoining section. 



Fig. J. Perpendicular section of black snake in the same region as Fig. i. 



Fig. 6-7 Horizontal sections of black snake brain illustrating hippo- 

 campus, lateral olfactory radix and nuc. sphericus. 



PLATE IX. 

 (Omitted, will be printed in a subsequent number.) 



PLATE X. 



Sections from the brain of the turtle (Cisfudo). 



Fig. 1.-6. Horizontal sections at various levels. Fig. i illustrates the 

 primitive simplicity in development of the cortical and rhinalic areas from a 

 large vesicle. The distinction between cortex and axial portion is very slight. 

 Sup. com. tr. tract from supracommissure, rad, I. radix lateralis, br. optic brach- 

 ium, /. c. postcommissure, mid. p. medi-pedun'cle of cerebellum. In Fig. 4, at 

 X, the transition of the hippocampal cortex into the occipito-basal lobe is readily 

 seen. In Figs. 3 and 5 the entrance of the lateral olfactory radix is also seen. 



Fi^. 7. Horizontal section through dorsal part of the cerebrum of the 

 snapping turtle (Ckelydra) . 



Fsgs. 8, g. Longitudinal sections through the brain of Czj/«(/rt to illustrate 

 the topography. 



Fig. 10. A section through the tectum opticum from the horizontal series 

 of Cistudo figured above. 



