ARENICOLA. 



225 



foreign particles; in A. grubii and A. antillensis the sacs are closed, 

 and contain intrinsic otoliths of lime. 



FIG. 117. Dissection of lob-worm from dorsal surface. 



m., Opening of retracted buccal cavity ; /., gullet ; /., diverticula 

 on first diaphragm ; /'., cesophageal glands ; d. 2 dorsal blood 

 vessels ; ef 1 ., first efferent branchial ; g:, stomach intestine ; 6 ., 

 sixth nephridium ; ef 13 ., thirteenth efferent branchial; / J3 ., 

 thirteenth afferent Branchial; a. t anus; af^>, first afferent 

 branchial ; /., heart of left side. 



