144 JOUKNAL OF THE NEW JERSEY 



ing, elevated, obtuse, equal ridges, which are spotted with short, 

 brownish lines; wdiorls flat, suture not indented; outer lip bev- 

 elled to a thin edge, and lineated with dark-brownish ; inner lip 

 with a lime deposit. Greenish or pale-ashy ; throat white — L. 

 25; D. 15; An. 60°; Wh. 5; Ap. f.— Mass. and south. Rare 

 north ; abundant south. 



2. Lacuna, Tur. 



Shell turbinated, thin; aperture semilunar; columella flat- 

 tened with an umbilical fissure; operculum paucispiral. 



1. Lacuna vincta, Mon. Shell thin, ovate-conic ; spire pointed ; 

 whorls very convex, with faint lines of growth ; suture deep ; 

 aperture nearly circular ; outer lip sharp, pillar lip white, with 

 a wide and deep groove ending in a deep umbilicus. Color yel- 

 lowish, with sometimes 4 or 5 purplish or reddish bands. L. 12 ; 

 D. 8; An. 58°; Wh. 5; Ap. i.— N. J. and north. Abundant 

 north. 



Family 64. RISSOID/E. 



Shell small, spiral, turreted, usually ribbed, many-worled ; 

 aperture rounded with entire lip ; outer lip slightly expanded 

 and thickened. 



1. RissoA, Frem. 



Shell minute, conical, pointed, many whoiled ; peristome 

 entire, continuous; outer lip slightly expanded and thickened; 

 operculum subspiral. 



1. Rissoa aculeus, Gld. Shell ovate-cylindrical, fragile; whorls 

 convex ; suture deep ; surface covered with numerous, minute, 

 revolving lines, and traces of longitudinal folds near the apex ; 

 apex blunt ; aperture entire, oval, oblique. Light yellow^ish 

 horn-color. Animal white. L. 4; D. If; An. 23°; Wh. 6. Ap. 

 J. — New England. On stones and timbers at low water. 



2. Risoa exarata, Stim. Shell ovate, rather solid, imperforate; 

 whorls convex, sub-plicate posteriorly, and' with about 3 elevated, 

 distant, revolving lines on the up})er, and 8 on the lower one.. 

 Fuscous. L. 3; D. 11; An. 22°; Wh. 5; Ap. less than J.— 

 Nova Scotia to Hatteras. Rare. 



3. Rissoa minuta, Tot. Shell minute, conic, thin, polished, 

 elevated to an obtuse apex ; whorls convex, souicwhat shoul- 

 dered ; lines of growth ftiint ; aperture oval, entire ; outer lip 



