HABITS, ETC., OF OEREBRATULUS LACTEUS. 109 



The same thing happened when a dead squid was left in a 

 pail with some Nemerteans. One of them swallowed a long 

 arm of the squid^ and when its further progress was stopped 

 at the base of the arm it drew its body down in wrinkles 

 until as much of the digestive tube as possible had come in 

 contact with the arm. It remained in this position for five 

 or six minutes and then withdrew, leaving the arm com- 

 pletely digested for more than half its length. Of course, 

 there is very little substance to the body of a Nereis, and it 

 can be assimilated without much change ; but the arm of a 

 squid is more substantial, and must require considerable 

 digestion. It is evident that this takes place rapidly at the 

 very beginning of the alimentary canal. This fact suggests 

 one reason why the loss of the posterior portion of the body 

 does not seriously affect the animal. 



Several of the fishermen have told me that specimens of 

 Cerebratulus are sometimes caught by them when fishing in 

 shallow water with a bait of Buccinum undatum or 

 Natica heros. 



The same thing is noted by Mcintosh (34) with reference 

 to the deep-sea form, Lineus marinus, which was caught 

 while fishing for cod. Like that species, Cerebratulus also 

 must have an indiscriminate appetite,'^ feeding upon both 

 living and dead forms, and ejecting the bristles and other 

 indigestible material through the anus. Occasionally a 

 bristled or spiny victim proves too much for its captor, with 

 the result that the bristles or spines perforate the digestive 

 tract and the body-wall. 



Dr. W. R. Coe tells me that he found a Cerebratulus in 

 this condition with a large Nereis half swallowed, the poste- 

 terior portion of the Nereis protruding through a large rent 

 in the ventral wall of the oesophagus. In confinement Cere- 

 bratulus eats readily almost any animal food, but prefers a 

 Nereis to anything else. 



Breathing. — This species and probably most other Ne- 

 merteans breathe by means of the walls of the oesophagus. 



With the incoming tide the Nemertean opens the anterior 



