SPECIAL CUTANEOUS SUBDIVISION. 



^31 



in the more highly developed portions. This can be illustrated 

 best by describing the cutaneous centers with their roots and 

 secondary connections in some detail. As stated above (p. 115) 

 the general cutaneous fibers on entering the brain go in part by 

 the spinal V tract to the nucleus of the dorsal funiculus and in 

 part spread widely through the acusticum and cerebellum. The 

 neuromast components also spread widely through the acusticum 

 and cerebellum but only a small part of them go to the nucleus 

 funiculi or to a small nucleus adjoining it. Thus the greater 

 part of the nucleus funiculi, and, especially in higher vertebrates, 



V^; 



-I -r^:^ 



Cerebellum 



L. lineae lateralis 



N. lin. lat. VII 

 N. VII sensory 



-N. VII motor 

 Secondary gustatory 

 tract 



Spinal \' tract 



Fig. 64. — A transverse section of the brain of the sturgeon at the level of the 

 VII and VITI nerves. 



cells accompanying the spinal V tract are related to general cu- 

 taneous components alone, while in the acusticum and cerebellum 

 both general and special cutaneous fibers intermingle and pre- 

 sumably end in relation with the same cells. The intermingling 

 of these components will be seen by reference to Figs. 64 and 65. 

 In the acusticum and cerebellum there is to be noticed a great 

 increase in size in true fishes as compared with cyclostomes and 

 the presence of much more prominent granular and molecular 

 layers. The outer portion of the cerebellum is composed of a 

 dense layer of very fine fibers, interspersed with few cells, which 

 continues caudally over the dorsal or lateral surface of the acus- 



