mssoA. 297 



Rissoella? eburnea. 



Rissoa eburnea, STiMPSO>r, Proc. Bost. Soc. iv. 14 (1S51) ; Shells of New England, 34, pi. 



l.fig. 1. 

 Rissoella? eburnea, Stimpsox, Check Lists, 4. 



Shell small, ovate-conoid, white, shining, smooth ; whorls Fig. 564. 

 four, rather convex, sub-angulated at suture ; aperture ovate- 

 elliptic ; peristome thin, simple, acute, eftiise anteriorly. 

 Length, sixteen hundredths of an inch ; breadth, nine hun- 

 dredths of an inch. 



This species resembles some varieties of R. ventrosa, but 

 is much more angular. Two specimens were taken in thirty 

 fathoms, off Cape Ann (^Stimpsoii). 



Rissoella sulcosa. 



Shell minute, ovate-conic, sniooth ; whorls four, sub-convex, transversely fur- 

 rowed ; suture impressed ; aperture ovate-oblong, transversely banded within. 



Plmsinndla sulcosa, Mighels, Bost. Journ. iv. 348, pi. 16, fig. 4 (1843). 

 liissoella ? sulcosa, Stimpson, Clieek Lists, 4. 



Shell very small, ovate-conical, smooth and white ; whorls four, 

 sliglitly convex, Avith six or seven transverse grooves on 

 the body whorl, and three on each of the two next above, 

 spire smooth and pointed ; aperture ovate-oblong, with 

 three slightly apparent transverse bands within, as seen ^ 

 under a strong magnifying power. Length, one tenth 

 of an inch ; breadth, about one twentieth of an inch. 



^^ R. sidcosa. 



Casco Bay. 



Examined with the unassisted eye, this shell would be likely to 

 be mistaken for some species of Cing-iila, but its true character is 

 revealed with even a moderate magnifying power, the lip being in- 

 conlinuous posteriorly. I have never discovered but one specimen 

 of this curious little shell ; this I found in the stomach of a had- 

 dock, in the summer of 1842. I presume it is the only representa- 

 tive of the genus that has been hitherto discovered on our Atlantic 

 coast {3Iig-hels). 



Ociius RISSOA, Fremenville. 1814. 

 Shell usually white, solid, conical; spire pointed, many whorled, 

 whorls convex and smooth, or longitudinally ribbed ; aperture ovate; 

 outer lip more or less dilated and thickened externally. 



