VII. On the Anatomy and Habits of Nereis virens. By 

 Frederick M. Turnbull. 



Read January 19, 1876.* 



The Nereis [Alitta) virens^ which is one of the Largest and most 

 common of our marine annellids, is found under stones or burrowing 

 in the sand and mud of sheltered shores, both at low-water mark, 

 and at a considerable distance farther up. It grows to the length of 

 eighteen inches or more, and is quite stout in its proportions. 



It is very active and voracious, feeding on other worms and vari- 

 ous kinds of marine animals which it finds when burrowing in the 

 sand.f It will even devour its own immediate relatives, if hungry 

 when it meets them. It suddenly thrusts out its proboscis and 

 seizes its prey with the two powerful jaws, then withdraws the pro- 

 boscis, the jaws closing at the same time. In this way it 

 w'ill tear large pieces from the body of its victim, being able, at 

 one bite, to cut in two a worm of its own size. One which I had 

 confined in a small dish of water, bit its own body in two pieces 

 at the middle. As the proboscis is turned inside out, when it is pro- 

 truded, whatever has been siez<'d by the jaws will be drawn by them 

 inside the proboscis as soon as the latter resumes its natural jjosition, 

 the proboscis then acting as a sort of gizzard. 



These worms, by secreting a viscid fluid, will surround themselves 

 in a few minutes with a translucent sheath which binds the grains of 

 sand together, forming a loose and flexible tube. They remain most 

 of the time in these tubes, Avhich are nearly always situated in sand 

 and mud or under flat stones, and they move in them with consider- 



* Abstract of a graduation thesis presented at tlie Sheffield Scientific School, June, 

 1875. 



f Later observations show that this species does not restrict itself to an animal 

 diet. Several large specimens, taken by me in October, 1875, had the intestine com- 

 pletely filled witli algte of several species, among which Ulva latissima was most 

 abundant. The algas were torn into fragments and large shreds and rolled together 

 into long pellets, but even after passing through the intestine their nature could be 

 easily recognized. — a. k. verrill. 



Trans. Conn. Ac.\d., Vol. III. 34 August, 1876. 



