6o8 'Journal of Comparative Neurology and Psychology. 



and contains a large clear nucleus ^yith sharply defined nucleolus. 

 The resemblance of these cells in fonn and structural appearance to 

 spinal ganglion cells has been noted or used as a means of description 

 by Meynert and most later authors. This comparison is not only apt 

 as far as general appearance is concerned, but in every particular a 

 close resemblance can be drawn. The size, the vesicular form, the 

 possession of small dendrites, the bipolar form with one thick and 



B 



Fig. 8. Two camei'a drawings from a transverse section of the brain of a 

 human embryo of 15.5 mm. (Embryo H. 19.) A, the cells and fibers of the 

 radix mesencephalica ; B. some cells of the motor nneleus of the trigeminus. 

 The magnification is the same in both figures. Only the nuclei are to be seen 

 in most of the cells. 



one slender process are all duplicated by adult or embryonic spinal 

 ganglion cells. The internal structure also is like that of spinal 

 ganglion cells, even to the disposition of the neurofibrillse, so far as 

 these are shown in my silver preparations. In position also these 

 cells correspond perfectly to the giant cells in the spinal cord of 

 fishes and amphibians and to the cells in Amphioxus which are 

 homologous to the spinal ganglion cells. 



