214 MOLLUSCA. 
~ 
It has a general resemblance in size and form to N. maroccana, and 
the shells from the Mediterranean allied to it; but is more solid, and 
differs from all in its umbilical channel, which is uncovered exter- 
nally, and is below the funiculus, and not above it. Its network 
colouring is peculiar, looking much like that on the pale bands of 
Conus ammiralis. \t most nearly resembles a shell which I suppose 
to be N. lupinus, Desh., which has a nearly similar columella, form, 
and solidity, with a simply banded colouring. 
Figures 255, 255 a, front and back view of the shell. 
Natica aLerpa (Gould). 
Testa parva, tenuis, globosa, glabra, albido-livescens : spira anfractibus 
quatuor ventricosis juata suturam linearem tabulatis, ultimo magno 
ampullaceo : apertura semilunaris ; columella arcuatd: basis umbilco 
modico spirali funiculato, ad introitum angulato, perforata. 
Natica algida, Gouin; Proceed. Boston Soc. Nat. Hist., in. 73. 
November 1848. Expedition Shells, 50. 
SHELL small, rather thin, globular, smooth, of a pale bluish-white 
colour. Whorls four, forming a rounded, slightly elevated spire, the 
last one very capacious, with a narrow shoulder near the suture. 
Aperture semilunar, outer lip thin; inner margin curved, covered 
posteriorly by callus, which is not very closely appressed. ‘There is 
a rather large, open, somewhat spiral umbilical opening, externally 
margined by an angle, and partially filled by a revolving pillar, on 
which is an expansion of the callus. 
Axial diameter five-eighths of an inch; transverse diameter three- 
fifths of an inch. 
Dead specimens were obtained at Classet, Oregon. 
Differs from N. soluta principally in its sutural region, and in its 
umbilical region, in which latter respect it differs from several allied 
species, such as NV. globosa, N. boreahs, &c. 
Figures 256, 256 a, ventral and dorsal views of the shell. 
