130 COMPARATIVE ANATOMY chap. 



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



— F 



Fig. 111.— Diagram of the nervous system of Chiton siculus (after Bela Haller). Tlie mantle 

 removed on the riglit siilc In the centre and to the left the upper part of the foot removed, to 

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

 oesophageal ring ; 1, 2, nerves of the cesnpliageal ring ; f, connective to the anterior visceral ganglia ; 

 p, connective to the ganglia of the subradular organ n (above on the left) ; Es, pleuroviseeral and 

 pedal cords ; mji, gastric nerve ; So, point of attachment of the sphincter oris ; n (below on the 

 right), n\, 11-2, nephridial nerves ; m, pallial nerves ; p (to the right below), cardial nerves; v, a 

 dorsal nerve of one of tlie 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. Tliis ganglion lies in the sub- 



