l8o JOL'KNAL OF CoMPAKATlXE NeIIKOLOGY. 



PLATE XI. 



-Fiffs. 1-lJ. Transections of the brain of Scap/tir/iviic/iiis. 



Fig. 1. Section of the olfactory lobe. Dorsallj the cephalad ex- 

 tension of the lateral ventricle occupies the median aspect. Laterally 

 the olfactory nerve fibres are emerging. 



Fig-. 2. Portion of transection of the anterior part of the cerebrum. 

 The median walls of the ventricle are not naturally represented, partly 

 because of obliquity and distortion of the section. The opening of the 

 olfactory ventricle is into the lateral ventricle, which is connected with 

 a median aula by the foramina of Monro. 



Fig. S. Section near the posterior margin of the olfactories, some- 

 what oblique, so that the right side passes through the olfactory while 

 the left cuts the ala alone. The ala on the right side lies dorsad to the 

 olfactory, and is separated from the basal portion of the cerebrum by a 

 fissure. 



Fig. 4. Section through the superior commissure; the loop of the 

 membrane to the left is to be ignored. The hypoaria occupy the whole 

 ventro-lateral aspects. 



Fig. 5. Section through the posterior commissure. M. />., Mey- 

 nert's bundle. 



Fig. 6. Section through the optic lobes. The ventricles of the 

 hypoaria are confluent. 



Fig. 7. Section at the exit of the third nerves. The volvula occu- 

 pies the cavity of the optic lobes. 



Fig. 8. Section near the anterior margin of the medulla. 



Figs. 9-12. Sections farther caudad. 



Fig. 13. Cells from the apparent origin of the third nerve. 



Fig. 14. Cells from the cerebellum. 



Fig. 1.5. Ventral surface of the entire brain. 



PLATE XIL 



Figs. IS. Portion of horizontal sections of the black-snake brain, 

 to show the relations of the pr;ccommissura, callosum, fornix, etc. 

 Fig. I lies farthest ventrad. /., fornix; l).o.tr., occipital portion of the 

 praecommissura; l.f., parietal portion; ac/ , frontal, or " olfactory " 

 portion. Compare with Figs. 7 and 8. 



Fig 4- Cells from the Gasser's ganglion of the turtle. 



Fig. 5. Longitudinal perpendicular section through the middle of 

 the hemispheres of the brain of an embryo of the black-snake. 



Fig. 6. Longitudinal horizontal section of the brain of a black- 

 snake. 



Fig. 7. Diagram to illustrate the principal tracts and niduli of the 

 brain of the black-snake, formed by the composition of several sections. 

 o.c, olfactory cortex; i.e., that portion of the cortex lying upon the crus 

 olfactorii; o, tract connecting the above with the frontal region; c.r., 



