522 Howard Edwin Enders. 



green color than in the earlier stage just described but less than in 

 the fully transformed larva. This color is undoubtedly due to the 

 same cause as that found in the dilated green intestine of the adult 

 Chcetopterus. The intestine is a dilated tube within the palettes 

 but is much narrower in the small posterior region. 



Feeding. — The large size and rapid growth of the larvse are due to 

 their voracious habits. Nearly all the specimens collected in the 

 towings were gorged with pellets of ingested matter. ]\Ianv of those 

 pellets contained the chitinous skeletons of small copepods, but the 

 contents of others could not be determined because of complete diges- 

 tion or the absence of skeletal structures. 



In order to study their habits of feeding I put one of the oldest 

 larva3 into a small dish of sea-water in wdiich were several copepods, 

 a small planarian, Nocfiluca and diatoms. The larva moved along 

 the bottom among the diatoms and when its post-oral lobe (ventral 

 lip) came into contact with the planarian the mobile pre-oral lobe 

 was pressed down upon it, the cilia vibrated rapidly and the planarian 

 was swept into the buccal funnel. It was then rolled about and 

 rotated several seconds by the cilia and muscular walls of the funnel 

 till it was reduced to a mucus-coated pellet, and was then swallowed 

 by a gulping movement of the muscular esophagiis. Less than ten 

 minutes later the same larva captured and swallowed a copepod 

 nearly half its size. The capture was accomplished rather by the 

 movements of the copepod than by any active attack of the Chsetop- 

 terus larva. The copepod after moving among the masses of diatoms, 

 suddenly darted to the margin of the spacious buccal funnel ; it was 

 swept into this by the cilia and was unable to escape. Another 

 Chsetopterus larva swallowed E'octiluca in the same way. Diatoms 

 were also swept into the gullet and swallowed by the oldest larvae. 

 The cilia of the funnel seem to perform a tactile function, for they 

 discard grains of sand that are taken in with the diatoms. In 

 another instance a metamorphosing pluteus was discharged from the 

 buccal funnel by reversal of the cilia after it had been rotated once 



lior twice. The protruding sharp ends of the skeleton may have irri- 



f tated the larva and caused the discharge. 



Creeping habits. — Before this stage in its development is reached 



