A. K Verrill — Marine Nemerteans of New England, etc. 427 



Long Island Sound to Vineyard Sound, in 2 to 24 fathoms ; Bart- 

 lett's Reef, 22 fathoms, 1874. Usually taken on shelly or stony 

 bottoms among algje, ascidians, and hydroids ; common, es})ecially in 

 Vineyard Sound. The specimen figured was taken at Wood's Holl, 

 July 14, 1875. 



DOUBTFUL SPECIES. 



Lineus truncatus (flubr.) Veniii. 



Cerebratulus truncatus Hubrecht, Voyage of the Challenger, vol. xix, pp. 37, 50, pi. 

 1, figs. 11, 12, 1887. 



This species was described from imperfect alcoholic specimens, so 

 that its external form and color in life are entii'ely unknown. 



In the contracted speidraens the head is short, flattened, truncated 

 in front ; the cephalic slits are short and run forward close to, but 

 do not join, the proboscis-pore ; the mouth is small, rounded, and 

 only a short distance back from the front. 



Ofl:'Nova Scotia in 75 and 85 fathoms ; also off Bermuda. (Chal- 

 lenger Exp.) 



The S)nall mouth, rounded l)ody, and general appearances of the 

 specimens, as figured, indicate that it belongs to Linens or Micrura, 

 and not to Cerehratulus, as here defined. There is nothing in the de- 

 scription to distinguish it from Lineus viridis, which often contracts 

 into the same form. 



Micrura Elueuberg, 1830. 



Micrura (pars) Mcintosh, Nemerteans, p. 196. 

 Gerehrattdm (pars) Hubrecht. 



Body, head, and proboscis nearly as in Lineus ; body elongated, 

 terete or somewhat flattened ; the posterior regions usually not 

 much flattened, nor very different in form from the region of the 

 proboscis. Cephalopori or olfactory slits well defined. Ocelli some- 

 times present, but often wanting. Posterior end of the body pro- 

 vided with a median slender cixTus, above the anus. 



This genus, as here defined, differs from Lineus in little else than 

 the presence of a well marked contractile anal cirrus, which may 

 often be distinguished even in alcoholic specimens. From Cerebra- 

 tulus, which also has the anal cirrus, it differs in the form and mus- 

 cular structure of the bod}^ posteriorly, which is not very flat and 

 thin, nor adapted for swimming, as in the latter. 



Tkans. Conn. Acad., Vol. VIII. 56 June, L892. 



