134 



NERVOUS SYSTEM OF VERTEBRATES. 



as of two main types with intermediate forms. The first type 

 consists of cells with large bodies and rather coarse dendrites 

 whose many branches spread widely through the granular layer. 

 These cells show no special arrangement and no great pecuUari- 

 ties; they are most like the large cells in the dorsal horn of the 

 cord or in the nucleus funiculi. Their neurites go as internal 

 arcuate fibers to join the tractus bulbo-tectalis of the opposite 



Fig. 67. — Transverse section of the acusticum of the sturgeon to show acusticum 

 cells and a Purkinje cell, ex., cerebellar crest; L.v., lobus vagi. 



side of the brain. These cells will be referred to as acusticum cells. 

 Such cells are shown in Fig. 58 A, from the acusticum of a cyclos- 

 tome and in Fig. 67 from the sturgeon. 



The cells of the second type are also large but they differ from 

 the first in having both a special arrangement and a special form 

 differentiation. The cell-bodies stand in the granular layer 

 next to the molecular layer and are somewhat elongated vertically 



