MARINE MOLLUSCA OF THE UNITED STATES. TE 
Synopsis of Genera. 
Shell turreted, many-whorled, generally reticulate or granular with indis- 
tinct varices ; canal produced in front and slightly recurved ; columella 
thickened, with a callosity at the hind part. CERITHIUM, Adanson. 
Aperture with a slight canal in front, not produced or recurved ; inner lip 
acute, not reflexed or expanded. \ Brirtium, Leach. 
Shell sinistral ; aperture round, produced anteriorly into a closed, tubular 
canal, sometimes with a posterior, closed canal. TRrPHORIS, Deshayes. 
Genus CERITHIUM, Adanson. 
Hist Nat. Senegal. 153. 1757. 
1. C. FERRUGINEUM, Say. Fig. 126. 
Am. Conch., t. 49, f.3. 1882. 
Shell oblong-conical, with longitudinal ribs rendered nodulous 
by revolving elevated striz ; ribs about twenty on the body-whorl, 
almost interrupted by the interstices of the striw#; strize about 
seven with intermediate smaller ones on the body-whorl, and but 
three on the second whorl; volutions seven, suture inconspicuous ; 
aperture oblique, oval, whitish within; labrum slightly thickened 
on the exterior margin and with obsolete impressed lines on the 
inner side corresponding with the exterior striz ; color ferrugi- 
nous. 
North Carolina to Florida. 
Genus BITTIUM, Leach. 
Gray, Zool. Proc. London. 1847. 
This group includes several northern forms, smaller than the 
typical Cerites, and resembling dextral Triphores; they range from 
low water to eighty fathoms. 
1. B. nigrum, Totten. Fig. 127. 
(Pasithea) test. juv. Am. Journ. Sci., xxvi. 369, t. 1, f. 7. 1884. 
Cerithium reticulatum, Totten, ibid. xxviii. 352, f. 8. . 1835. 
Cerithium Sayi, Menke, Gould, Invert. Mass. 1st Edit. 278, f. 188. 1841. 
Shell small, acute, conic, thin. Whorls from six to eight with 
a distinct shoulder formed by a series of granules. Surface granu- 
lar from the crossing of slightly elevated folds with elevated spiral 
lines; about twenty of these ribs, which disappear on the lower 
half of the body-whorl leaving there only about six slightly elevated 
revolving lines. Suture deeply impressed. Aperture about a 
fourth of the length of the shell, elongate, subovate, acutely an- 
