Jelliffe, Cytology of the Brains of Some Amphibians. 153 



fused and all lying in the direction of the principal dendrite. 

 The nucleus is oval, has a delicate acidophile membrane and 

 contains a mass of acidophile granules. 



Dorsal cells of medulla — The cytoplasm of Triton is sparse. 

 In Spelerpes and Proteus it is not distinguishable ; nucleoli are 

 absent in all. 



Cells of tJic Palliiim. — No cytoplasm was observed in these 

 cells. The nuclei were oval. The granular olfactory cells 

 were lacking in cytoplasm ; the nuclei were oval. In the optic 

 lobes three types of cells were noted: (i) granules similar to 

 those of the olfactory lobes ; (2) granules larger than these and 

 richer in basophilic substances ; (3) cells with comparatively 

 abundant cytoplasm and containing fused chromophilic granules. 

 These have dark nuclei, which in Triton contain basophilic 

 granules and a homogeneous acidophile substance studded with 

 basophilic granules and in all a nucleolus of the usual character. 



Ependyma cells in all contained abundant cytoplasm. The 

 Italian author has not studied these brains from the same point 

 of view as that of the present writer, hence a correlation of the 

 results is somewhat difficult. From the standpoint of cyto- 

 plasmic development Spelerpes would represent the most prim- 

 itive type studied. , This would seem to be more primitive even 

 than Necturus, but for the reasons above stated it would be 

 premature to draw any conclusions. 



In Necturus we find a predominant type of nerve cells 

 which are indicative of a low grade of development. The chro- 

 mophilic granules are found in only a few of the cells and when 

 found are elementary or fragmentary in their construction, 

 those of the 7th nucleus appear to be the best developed. The 

 absence of any chromophilic granules in the cells of the pallium 

 is of interest. In Necturus, the chromophilic granules, espe- 

 cially those found in the 7th nerve nucleus, appear to be fibril- 

 lar in structure. 



Levi's investigations show a similar condition in the pallia 

 of Spelerpes, Triton and Proteus, while in Rana and Bufo a 

 small amount of cytoplasm is found collected in a small conical 

 mass lying to one side of the nucleus, generally the outer side, 



