INVEKTEBKATA. 13 



FIG. VII. 



THE WHELK. 



(BUCCINUM UNDATUM.) 



THIS figure shows the principal part of the nervous system in a ring divided into 

 two parts, and encircling a bloodvessel and the alimentary canal. The proboscis 

 has been turned aside for allowing some of the nerves to be seen terminating on this 

 part, and others on the fleshy foot. 



