CHAETOPODA 



153 



mouth to the terminal anus. The pharynx can be protruded, 

 and is then seen to be covered with papillae. The mouth opens 

 into the oesophagus, which bears at its hinder end a pair of 

 long glandular bodies, possibly homologous with the calciferous 



Fig. 97. — Anterior end of Arenicola piscatorum \&\& open 

 by a median dorsal incision to show the internal 

 organs. After Vogt and Yung. 



Proboscis beset with papillae. 



Muscles which retract the oesophagus. 



Diverticula which open into the hinder end of the 



oesophagus. 

 Stomach. 

 Intestine. 



and 7^'. 1st and 13th, or last, branchia. 

 Masses of chloragogenous cells. 

 Heart. 



Dorsal blood-vessel. 

 . Vessels to and from the branchiae. 

 Nephridia. 



glands of Lumlyricus (Fig. 97). The intestine, which traverses 

 the gill-bearing region, is coloured yellow by the presence of 

 yellow chloragogen cells in its walls, resembhng the similar cells 

 on the walls of the intestine in Zumbricus. These cells con- 

 tain concretions, which seem to be set free in the coelomic fluid, 

 and are possibly excreted by the nephridia. The walls of the 

 intestine are somewhat wrinkled, and are rather thin. The 



