MARINE MOLLUSCA OF THE UNITED STATES. TT 
3. S. GR@NLANDICA, Chemnitz. Fig. 139. 
S. subulata, Couthouy, Bost. Journ. Nat. Hist., ii. 93, t. 3, f. 4. 1838. 
S. planicosta, Kiener, Iconog., t. 7, f. 21. 1838. 
Shell tapering to a fine point, imperforate; whorls nine or ten, 
contiguous, slightly convex, with eight to fifteen stout compressed 
oblique ribs, with intervening coarse rounded vertical ridges, and 
seven or eight revolving striz; the ribs not ending abruptly at 
the suture, but flowing along the sutural region to the preceding 
ones; aperture nearly circular, bordered by a rib which is emar- 
ginate at the base; operculum horny, shining. 
Length 25, diam. 8.75 mill. 
Animal yellowish-gray with whitish spots; mouth rather large, 
rounded, corrugated. 
Arctic America (EHur.). 
4, §. ANGULATA, Say. Fig. 140. 
(S. clathrus, Linn. var.), Amer. Conch., iii. t. 27. 1831. 
S. Humphreysii, Kiener, Iconog. 1838. 
Shell conic, turreted, imperforate, white, immaculate; whorls 
‘six to eleven, touching each other only by the ribs, but with a 
very narrow interval; ribs nine to each volution, prominent, sim- 
ple, a little oblique, somewhat recurved, and with a more or less 
obvious, obtuse angle or shoulder above, near the suture; aper- 
ture suborbicular; base a little angulated; labium distinct. 
Length 15 to 20 mill. 
Described by Mr. Say as a doubtful variety of S. clathrus, from 
which it is distinct. 
New England to Florida. 
5. S. rurBINaTA, Conrad. Fig. 141. 
Journ. Philad. Acad. Nat. Sciences, vii. 263, t. 20, f. 26. 1837. 
Shell with the body-whorl dilated; ribs lamellar, strong, very 
prom.nent, slightly reflected, terminating above in a prominent 
angle; color white. 
Beaufort, North Carolina. 
6. S. MULTISTRIATA, Say. Fig. 142. 
Amer. Conch., ili. t. 27. 1831. 
Shell conic, turreted, tapering to an acute apex, white, immacu- 
late, imperforate ; whorls about eight, in contact; coste regular, 
simple, not reflected, equidistant, moderately elevated; spaces 
between the cost with very numerous, approximate, equidistant, 
