384 A. E. Verrill — Marine Nemerteans of Nev^ England., etc. 



otherwise would have been, because many of our native species are 

 closely allied to, and several others are identical with, some of those 

 that have been well studied anatomically by Mcintosh and other 

 European writers. 



Nemerteans are almost universally present on our shores, between 

 tides at all levels, from near high-water [Lineus socialis) down- 

 ward. They are also to be found, by dredging, at all depths down 

 to 1000 fathoms or more, but are much more abundant in shallow 

 water (1 to 60 fathoms) than at greater depths. They occur on 

 all kinds of bottoms, but are usually more abundant in soft and 

 partially organic mud than elsewhere. But in rather shallow water, 

 on some hard bottoms overgrown with ascidians, hydroids, and 

 sponges they are often very abundant, especially in the Bay of 

 Fundy. The littoral Nemerteans occur in greater numbers and of 

 more numerous species on the rocky shores of the Bay of Fundy, 

 and especially in Eastport harbor, than in any other localities where 

 I have collected them. 



On sandy shores, also, there are nearly always several species 

 living buried in the sand, to be found easily by the use of a spade. 

 These sand-dwelling forms include the largest species of Cerebratu- 

 hcs, which are, perhaps, the largest of all Nemerteans. 



NEMERTINA. 



The Nemertinea may be characterized as follows: 



Smooth, ciliated, often bright colored, and mostly marine worms, 

 destitute of external paired apjjendages, usually wuth a long and 

 somewhat flattened body, often almost linear; without definite body- 

 cavity. Muscular walls of body thick and complex, not segmented. 



Head not very distinct from the body; mouth ventral, beneath 

 the head, or subterminal, without teeth or jaws. 



Intestine large, usually straight and furnished with many short, 

 lateral, saccular, often lobed appendages; anus posterior. 



A long, tubular, dorsal proboscis is contained in a special muscu- 

 lar sheath, which is filled with a corpusculated fluid and situated 

 above the intestine but entirely separated from it. The pi'oboscis 

 can be protruded by eversion from a special aperture at the front 

 of the head. 



Two pairs of cephalic ganglions are present ; they are united 

 transversely by an upper and a lower commissure, between which 

 pass the proboscis and its sheath. Most species have ciliated pits or 

 sacs connected with the posterior ganglions by ducts leading from 



