Herrick, Brain of Ceitain Reptiles. 99 



trad of which is the nidulus of the oculomotor, but many of its 

 fibres pass toward the ventral surface. 



10. At the level of the oculo-motor nidulus the decussa- 

 tion of the raphe is prominent. The passage of the dorsal ped- 

 uncle into the cerebrum from the geniculatum is also seen at the 

 level of the prsecommissure. The lemniscus fibres diverge to- 

 ward the lateral aspect of the medulla and are adjacent to the 

 root of the trigeminus. The post-peduncle of the cerebellum 

 passes from the latero-ventral aspect of that organ and, turning 

 latero-ventrad, reaches a point somewhat cephalad of the trige- 

 minus, while the medi-peduncle continues nearly directly ven- 

 trad toward the pes. 



The cerebellum is continued ventrad as a tuber projecting 

 from either side into the fourth ventricle. The origin of the 

 fibres in the granule layer is very obvious. A strong nidulus 

 of rather large, flask cells lies cephalad of the above tuberosity. 



1 1 . The dorsal longitudinal fasciculus describes a sharp 

 ventrad curve and returns to its place along the floor of the 

 fourth ventricle. Meynert's bundles converge toward the med- 

 ian line. 



12. The vague nidulus ruber accompanies Meynert's bun- 

 dle, preserving nearly the same relation to it. The two optic 

 brachia collect entad of the optic tract. A large nidulus of 

 flask cells collects in the median part of the thalamus cephalad 

 of the ruber. It is perhaps the homologue of the nidulus sub- 

 thalamicus. The fibres of the superior peduncle seem to pass 

 into the caudo-dorsal parts. We cannot agree with those auth- 

 ors who urge that the whole cortex of the reptile is sensory if 

 not specifically olfactory. 



13. At a deeper level a strongly staining dense nidulus 

 appears caudo-mesad of the inferior commissure tracts, and thus 

 immediately cephalad of the midpeduncle tract from the cere- 

 bellum. Its cells are of the same peculiar sort described by us 

 in the "nidulus niger " of fishes. 



14. Still farther ventrad the fibres of the motor peduncles 

 can be seen entering the same nidulus. The relations are, 

 therefore, precisely as in fishes except that the hypoaria are not 



