676 
Nachdruck verboten. 
The Commissures and Histology of the Teleost Brain. 
By C. L. Heeeick, Prof. Neurology aud Comparative Psychology in the 
University of Chicago. 
With three Figures. 
The writer has recently discussed the topography of the ganoi- 
dean aud teleostean brain in a series of articles in the Journal of 
Comparative Neurology for June and October of the present year. 
This paper presents in outline some of the results, equally gratifying 
and unexpected, growing out of the minute study of a large series 
of serial sections from a considerable number of species of North 
American fishes. The complete paper with ample illustration will 
appear in the December number of the Journal where detailed account 
of the methods employed may be sought. It is sufficient to say here 
that a modification of the haematoxylin method has proven adequate 
to bring out with remarkable distinctness the various histological 
details, especially the minute differences between the different varieties 
of cells of the cerebrum. 
The fundamental difficulty in the interpretation of fish brains grows 
out of the fact that the cortex, though morphologically present is 
anatomically absent, i. e. it is represented, as shown by RÜCKHARD, 
by the pallium, an anatomically different structure. The question 
whether it is physiologically represented cannot fail to be of the 
utmost importance. The writer has endeavored to show in several 
papers !) that the axial lobe of Sauropsida is much more than the 
representative of the mammalian corpus striatum, i. e. that it inclu- 
des proliferating centres from which are derived the cortical cells which 
gradually migrate, or are carried by the slow growth of the parts 
into their definitive position. This was based in part on the several 
types of cells found in the axial lobe aud their relations to the 
cortex as well as upon the fact that rapid subdivision by fission is 
observed in certain regions of the axial lobe. This hypothesis: has 
received special confirmation from the researches of my pupil, Mr. 
TURNER, who in his studies upon the avian brain ?) has found several 
1) Notes on the Brain of the Alligator. Journal of the Cincinnati 
Society of Natural History, Vol. XII, p. 455; Contributions to the Com- 
parative Morphology of the Central Nervous System. II. Morphology 
and Histology of the Brain of certain Reptiles. Journal of Comparative 
Neurology. Vol. I, p. 21, March, 1891. 
2) Journal of Comparative Neurology, Vol. 1, March, June and October. 
