Ixxx Journal of Comparative Neurology. 



recently presented by him in various preliminary articles. We notice 

 little which is new and fear that his opponents will not find his morpho- 

 logical deductions in all respects satisfactory. 



The figures of Ammocetes given may be profitably compared with 

 Ahlborn's figures of Petroniyzon. Studnicka recognizes the cephalic 

 pallial fibres as a callosum. He finds two classes of cells in the cortex 

 of the pallium, the larger resembling the pyramidal cells of other ver- 

 tebrates. He concludes that in the Cyclostomata the hemisphere is 

 but an appendage of the bulbus and has no other function than 

 olfaction. 



A chapter is devoted to the embryology, the most important point be- 

 ing that the two hemispheres arise independently from the lateral massive 

 walls of the ventricle and not from a common proton. This as well as 

 other facts brought out accords with the present writer's deduction based 

 on the morphology and histology of the " basal lobes " of teleosts that 

 these lobes represent the elements of a cortex as well as of basal lobes 

 properly speaking. Studnicka maintains that in spite of some easily 

 recognized evidences of degeneration the brain of Cyclostomata is the 

 most primitive at our disposal. Difficulties are reached in construing 

 the development of the Selachii, which contains many " cenogenetic 

 peculiarities." We hope to give this whole subject a comparative re- 

 view and await the remainder of the author's investigation before ven- 

 turing a critique. C. L. H. 



