64 AMERICAN MARINE CONCHOLOGY. 
Genus OBELISCUS, Humphrey. 
Mus. Calonn. 1797. 
1. O. crENULATUS, Holmes. Fig. 110. 
Post Pliocene Foss. So. Car. 88, t. 18, f. 14. 1860. 
Shell subulate, smooth, angularly channelled at the suture, which 
is crenulated on the lower whorls only; columella with three folds, 
the superior one large and acute, the others small; outer lip with 
four small teeth internally; whorls fourteen to sixteen; with two 
indistinct opaque revolving bands, which are sometimes obsolete. 
North and South Carolina, 
Genus TURBONILLA, Risso. 
Hist. Nat. Eur. Merid., iv. 224. 1826. 
Chemnitzia, Orb. Webb and Berthol. Hist. Nat. Iles Canaries. 1859. 
1. T. InTERRUPTA, Totten. Fig. 111. 
(Turritella) Am. Journ. Science, xxviii. 352, f. 7. 1834. 
Shell small and slender, whorls ten, almost flat, on which are 
twenty to thirty transverse obtuse ribs, crossed by about fourteen 
subequal revolving lines interrupted by the ribs; these are 
arranged in pairs, so closely applied as often to be confounded in 
one; below the middle of the body-whorl, the ribs become obsolete, 
and the revolving lines are uninterrupted; a slight shoulder on 
each whorl causes the sutures to be quite distinct. Aperture 
ovate, sharply angular above; inner lip slightly everted. Whitish- 
brown or amber-colored. 
Length 6.25, diam. 2.4 mill. 
Mass. to North Carolina. 
2. T. NIVEA, Stimpson. Fig. 112. 
Proc. Bost. Soc. Nat. Hist., iv. 114. 1851. 
Shell aciculated, sub-cylindrical, white shining; whorls eleven, 
flattened, longitudinally plicate; folds straight, interstices per- 
fectly smooth. 
Length 7, diam. 1 mill. 
Animal white; head short; tentacles triangular, very broad, 
with the eyes at nearly the middle of their bases; foot elongated, 
with an arcuated indentation at its anterior terminus. 
This species differs from 7. interrupta in being more slender, in 
wanting revolving lines, and also totally in its station, the deeper 
parts of the Coralline Zone. Taken in forty fathoms, on a muddy 
and gravelly bottom. , 
Grand Manan Island, Bay of Fundy. 
