Herrick, Brain of Certain Reptiles. 127 



lareral aspect of the hemisphere where its fibres may be traced 

 cephalad for some distance. Other fibres pass into the thalamus 

 but they seem to be derived from the infra-habena or habena 

 rather than the supra-commissure. The results of the Golgi 

 method as applied to the turtle are in harmony with this case. 

 Plate XIX, Fig. 10. 



The Ventral Commissjire System is diffuse and much less 

 easily studied than in fishes. One element, the coinniissnra 

 horizontalis is sufficiently separable but consists of several bund- 

 les which keep approximately parallel. The fibres are first 

 detected in the cells immediately cephalad of the post commis- 

 sure, the "nidulus corticalis" of fishes or nidulus aqueductus 

 (mihi) of reptiles\ The fibres collect into two or three distinct 

 bundles which pass ventrad, traversing the whole extent of the 

 nidulus ruber (as this term was used by me in fishes and reptiles) 

 to near the ventral surface of the tuber. Its fibres pierce the 

 peduncles caudad of the post-commissural tract and cross upon 

 the ventral aspect of the tuber some distance behind the chiasm. 

 It is not a little gratifying that the agreement between the 

 course of these fibres in the Amphibia and the fishes should 

 prove so close. It seems to warrant the hope that we shall 

 ultimately determine homologies in detail from lowest to high- 

 est. The ventralis and transversa are not easily separable and 

 consist of disperse fibres arising from the cephalo-lateral aspects 

 of the diencephalon and decussate or cross from one side to the 

 other dorsad of the chiasm. We are forced to admit our inabil- 

 ity to find the mantle-bundle of Edinger which should connect 

 with our com. transversa. 



The peduncles in Anura sustain the same relations as in 

 fishes, complicated by the presence of the cortex. The ventral 

 peduncles enter the cerebrum far ventrad and pass into a strong 

 nidulus corresponding to a part of the striatum, many of the 

 fibres here affect union with cells whose opposite end is contin- 

 ued as a fibre extending cephalo-dorsad. The ultimate destina- 

 tion in the cortex seems to be the ventro-Iateral region and the 



^Journ. Neurol. Vol. III. p. 



