60 AMERICAN MARINE CONCHOLOGY. 
Genus NEVERITA, Risso. 
Moll. Eur. Merid., iv. 149. 1826. 
1. N. pupiicaTa, Say. Fig. 101. 
(Natica.) Journ. Phila. Acad. Nat. Sci., ii. 247. 1822. ° 
Shell solid, subglobose; whorls five, somewhat convexly flat- 
tened above; aperture oval, oblique; umbilicus irregular, with a 
deep furrow, and almost entirely covered by a thick callus. 
Color ashen-gray, within deep chestnut-brown; callus of the same 
color. 
Length 25-50, diam. 27-55 mill. 
New England to Georgia. 
Genus MAMMA, Klein. 
Ostracol. 21. 17538. 
1. M. immacuLaTa, Totten. Fig. 102. 
(Natica.) Amer. Journ. Sci., xxviii. 357 f. 6. 1835. 
Shell small, solid, longitudinally suboval. Whorl about five, 
the upper ones very slightly convex; apex short and pointed, su- 
ture not impressed ; the body-whorl convex and elongated be- 
neath. Aperture narrow, regularly and somewhat acutely curved 
at the base. Umbilicus rounded and deep, scarcely modified by 
the callus, which is not very copious, but forms a deposit under 
the upper part of the lip, and causes a white spiral line to appear 
externally just below the suture. Epidermis thin, greenish-yellow, 
beneath milk white. 
Length 7, diam. 5.5 mill. 
Maine to New York. 
Genus BULBUS, Brown. 
Proc. Geol. Soc., iii. 119. 1839. 
1. B. Smirui, Brown. Fig. 103. 
Vatica flava, Gould, Am. Journ. Science, xxxvili. 196. 1840. 
Natica aperta, Lovén, Index Moll. Scand. 1846. 
Shell globular, inflated, thin and light; whorls four, rounded, 
slightly compressed above near the suture, with very minute in- 
cremental and revolving strive; spire little elevated; pillar-lip 
with a curve in its middle; the callus contracting and obliterating 
the umbilicus, which is deeply indented ; epidermis light yellowish, 
white underneath; callus ivory white. 
Maine northwards (Hur.). 
