130 COMPARATIVE ANATOMV chap. 



in than the hiiccal connective, a nerve (the subradular connective) rises and runs 



Fig. 111.— Diagram of tlie nervous system of Chiton siculus (after B^la Haller). Tlie mantle 

 removed on the right side. In the centre and to the left the upper part of the foot removed, to 

 expose the pedal nen'-ous system. F, Foot ; A", last gill ; A, anus ; 0, upper, U, lower half of the 

 cesophageal ring ; 1, 2, nerves of the oesophageal ring ; c, connective to the anterior visceral ganglia ; 

 p, connective to the ganglia of tlie subradular organ n (ahove on the left) ; Es, pi euro visceral and 

 pedal cords; mn, gastric nerve; So, point of attachment of the sphincter oris ; ti. (below on the 

 right), ni, n-2, nephi-idial nerves ; m, pallial nerves ; p (to the right below), cardial nerves; v, a 

 dorsal nerve of one of the pedal cords. The commissures between the pedal cords are seen, and 

 the nerves running outwards from the latter. 



forward and inward to the subradular ganglion. This ganglion lies in the sub- 



