LESSON 80.] NERVOUS SYSTEM IN THE GASTEROPODA. 265 



dominal cavity beneath the intestine, to near the caudal extremity 

 of the trunk. A branch, constituting the sympathetic, extends 

 directly backwards from the brain, or 03sophageal collar, and is dis- 

 tributed to the viscera. Numerous branches come off from the 

 pedal ganglia (q), to ramify on the muscles of the foot and surround- 

 ing parts. The lateral ganglia of the nervous ossophageal collar are 

 the parts from which the two principal nervous chords are derived, 

 which extend backwards beneath the abdominal viscera. 



1196. The Buccinum (Whelk) and the Harpa have the greatest 



FIG. 881. 



Nervous system of Harpa elongata. 



portion of the ganglionic matter of the oesophageal nervous ring ac- 

 cumulated in a cerebral position above the entrance of the alimentary 

 canal, as shown in the annexed figure of the Harpa elongata (Fig. 381). 

 1197. The mantle (o) is opened to show the branchiae (d, e) and 



