376 



ARTICULATA: WORMS. 





w 



Lob-worm, Arenicola piscatorum. 



A, external form; B, internal structure as seen from above; C, as seen on the side. 

 ",, proboscis; 6, pharynx; e, retractor muscles; (7, crop; e, caeca! appendages;/; 

 stomach; y, Intestine; k, muscular partition; 'i-^i, branchiae; o, dorsal vessel. 



