15 



This shell differs from R. aculeiis, (Cingula acideus, Gould,) 

 in being shorter ; its whorls are much more compactly coiled, 

 and its revolving strise are stronger and more evident. The lip 

 is also more thickened. From R. Mighehii it differs in having 

 much more numerous and crowded transverse strise. 



It was dredged in 5 fathoms, off Gt. Misery Island, and also 

 near Nahant, on sandy and gravelly bottoms. 



RissoA MiGHELSii, nob. Cingula arenaria^ Mighels, Boston 

 Journ. Nat. Hist. IV. 49. This is not the Turho arenarius of 

 Turton nor of Dillwyn, nor is it identical with any other Euro- 

 pean species. It may take the name of its discoverer, who is 

 well known for the many additions to our Fauna which he has 

 made during his researches on the coasts of Maine. 



I have obtained a few specimens of this species from fishes 

 taken in deep water in the Bay. 



RissoA EXARATA, nob. n. s. T. parva, ovata, fusca, solidula, 

 imperforata ; anf. 5 convexiusculi, postice subplicati, costis 

 Iransversis, elevatis, inoequidistantibus, (tribus ad anf. supr.,) 

 — cincti ; apertura parva, ovata, labro incrassato. Long. .11 ; 

 lat. .05 poll. 



A single specimen of this very distinct species was dredged in 

 three fathoms, on a shelly bottom in Boston Harbor. It is dis- 

 tinguished by its very prominent, distant, transverse ribs, which 

 are three on the upper whorls and eight on the lower. Its aper- 

 ture is very small. 



RissoA PELAGiCA, nob. Cingula sernicostata^ Mighels, Boston 

 Journ. Nat. Hist. IV. 49. That this species is distinct from the 

 European shell to which it has been referred will be readily 

 seen by a comparison of it with the recently published figures of 

 Forbes and Hanley. It is somewhat abundant in deep water off 

 Cape Ann. 



TuRRiTELLA AcicuLA, nob. n. s. T. parva, turrita, subulata, 

 Candida, tenuis; anf. 10 valde convexi, longitudinaliter striati, 

 costis transversis, quarum tribus majoribus, cincti ; apertura 

 rotundata, antice eff'usa, labro acuto. Long. .22 ; lal. .08 poIL 



This species is distinguished from the young of T. erosa by 

 its much more convex whorls and prominent ribs. 



