Prosencephalon of Teleosts. 



standing of the evolution of the brain of 



higher vertebrate*. 



None of these homologies arc more importai 



it than those which 



relate to the commissures which may natur 



ally be taken as the 



points of reference. In this last mentioned 



1 direction a study 



of the Drum (II<i[>ln<]!ii<,tus) has fort una 



tely afforded the 



necessary clues. 





What follows is a brief summary of a 



detailed paper to 



appear in the December number of the Jam 





Neurology, forming part of a series whicl 



i has appeared in 



several previous issues. The methods pursi 



led will be given in 



full in connection with the paper, so that i 



t is only accessary 



to say that a modification of the laematox\\ 



[in process has been 



hit upon, which serves to sharplv differentiate 



■all the histological 



elements, bringing out the variations in ce 



11-structure beauti- 



fully. In fact a fish brain thus treated is his 



<t ©logically, instead 



of the least satisfactory, rather the most bea 



utiful of brain pre* 



parations. A large series of sections has 



been secured from 



which a few of the more important data art 



i here noted. 



First, in respect to histological differen 



tiation within the 



cerebrum. If the axial lobe of the fish cm 



?rebrum re] .resents 



functionally the entire brain, as would see 



in probable unless 



one claims that the fish leads a purely reflex 





that there should occur in it the various ty 



pes of cells which 



characterize the several regions of the cortex 



in higher animals. 



The writer has abundantly shown in a sei 



■ies of publications 



higher vertebr 



