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University of Califoniia Fublkations in Zoology [Vol. 16 



The mouth opening (figs. 1, 2, mth.) lies anterior and dorsal to the 

 margin of a prominent scoop-shaped lip (fig. 2), and the tips of the 

 long bristles that form the sides of the trough reach beyond the lateral 

 margins of the scoop so that the anterior end of the funnel is com- 

 pleted on the ventral side by the lip (fig. 1). The cluster of grains is 

 held immediately behind the mouth, in the pocket formed by the 

 ventral and lateral portions of the lip and the wall of the body 

 dorsally. The pellet is taken through the mouth into the gut when the 

 upper end of the esophagus is widened by the action of dilator muscles, 

 as noted by Dakin (1908, p. 776), and when in the stomach it is car- 

 ried back and forth by peristalsis. 



rig. 2. A view, from tlie right side, of the head of Eucalanus. No append- 

 ages are shown; the prominent lip appears beneath the head, and the opening of 

 the mouth (mth.) is indicated (above the lip) from which leads the oesophagus 

 (oes.). 



The stiff, heavy bristles on the inner lobe of the maxilla (fig. 1, 

 mxl.), are used to crowd the mass more closely under the lip. They 

 do not move very often, but it is not difficult to determine what their 

 part is. They act much like fingers in keeping the pellet in position. 



After the pellet has been formed and held in position, it often 

 happens that it is broken up and the particles are scattered widely. 

 This is accomplished by a backward sweep of the bristles in the sides 

 of the trough, aided to some extent by a movement of the bristles on 

 the inner lobe of the maxilla in the same direction. I have not ob- 

 served that the anterior maxillipeds make any other movements than 

 those that lead to the dispersal of the pellet. I have not been able to 

 determine what the jaws of the mandibles do, though it seems probable 

 that they are used to break up objects that are too large to be taken 

 through the mouth. 



