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 
Fic. 97.—Anterior end of Avrenicola piscatorum laid open 
by a median dorsal incision to show the internal 
organs. After Vogt and Yung. 
. Proboscis beset with papillae. 
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moo tb et 
. Oesophagus. 
. Muscles which retract the oesophagus. 
ES 
DABLST ae. 
. Diverticula which open into the hinder end of the 
oesophagus, 
5. Stomach. 
6. Intestine. 
71 and 71°, 1st and 13th, or last, branchia. 
. Masses of chloragogenous cells. 
. Heart. 
10. Dorsal blood-vessel. 
. Vessels to and from the branchiae. 
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. Nephridia. 
glands of Lumbricus (Fig. 97). The intestine, which traverses 
the gill-bearing region, is coloured yellow by the presence of 
yellow chloragogen cells in its walls, resembling the similar cells 
on the walls of the intestine in Lumbricus. 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 
