ARENICOLA. 



'97 



Food canal. — (1) The buccal cavity is protrusible as a 

 "proboscis" or introvert, which grips the sand, and bears 



Fig. 87. — Dissection of lob-worm from dorsal surface. 

 M., Opening of retracted buccal cavity ; z\, gullet ; gl '., diverticula 

 on first diaphragm ; gl"., oesophageal glands ; d., dorsal blood 

 vessels ; ef ., first efferent branchial ; £-., stomach intestine ; n$., 

 sixth nepnridium ; ef ls ., thirteenth efferent branchial; a/" 13 ., 

 thirteenth afferent branchial; a., anus; a/" 1 ., first afferent 

 branchial ; h., heart of left side. 



