THE CBRBBRO-SPINAL SYSTEM OF NERVES. 589 



in the gray matter for the supply of the internal and the exter- 

 nal parts of the hody — i. e., into splanchnic and somatic nerves. 

 The centers of origin of the splanchnic nerves are referred to 

 groups of cells in the gray matter of the cord around the cen- 



Fia. 4S7. 



Fig. 428. 



Pig. 427.— Ganglion cell from sympathetic ganglion of frog; greatly magnified, and 

 showing both straight and coiled fibers (after Quain). 



Fig. 428. — ^Multipolar ganglion cells from sympathetic system of man, highly magni- 

 fied (after Max Schultze). a, cell freed from capsule; b, inclosed within a nu- 

 cleated capsule. In both the processes have been Droken away. 



tral canal ; whUe the somatic nerves spring from the gray cor- 

 nua and supply the integument and the ordinary muscles of 

 locomotion, etc. The splanchnic nerves supply certain muscles 

 of respiration and deglutition, derived from the embryonic 

 lateral plates of the mesoblast; the somatic nerves, muscles 

 formed from the muscle-plates of the same region. 



■ It is assumed that the segmentation of the vertebrate and 

 invertebrate animal is related; and that segmentation is pre- 



