GASTEROPODS 385 
than we are giving our specimens. They are O. interfossa, a small shell 
with deep spiral grooves, sharp varices, and deep sutures; and O. cir- 
cumtexta, also small, but heavy, short-spired, with scalloped or crenu- 
lated outer lip. 
Genus Cerostoma 
C. nuttallii. A species belonging to the southern coast of California. 
It may be recognized at once by two prominent characters : first, a horn- 
like projection from near the base of the outer lip, and, second, the tumid 
varices alternating with rounded knobs. It has no spiral series of lines 
like those in Pteronotus festivus ; and it has a row of five or six little teeth 
upon the inner side of the aperture, like those in Ocinebra poulsoni. The 
anterior canal is closed. It is about two inches long. (Plate LX XII.) 
C. foliatum. A shell somewhat like the last, but almost twice as 
large, with heavy !wing-like varices (three upon each whorl), made up 
of overlapping plaits. The knobs between the varices are much smaller, 
while the revolving ribs, though fewer in number than in most of these 
west-coast murices, are heavy and large. The aperture is oblong, the 
anterior canal closed. There is a ‘‘ horn” near the base of the aperture, 
as in C. nuttallii, but no row of teeth upon the under side of the lip. 
The color is dingy white. (Plate LXXII.) 
In the waters of Oregon and Washington there are a few trophons and 
other forms similar to the east-coast genera. These no doubt belong to 
the boreal and arctic faunal provinces, and have spread over both the 
Atlantic and Pacific northern regions. 
SUBFAMILY PURPURINE 
This is considered a subfamily of the Muricide, and the group 
therefore bears the subfamily termination -inw. There is no 
vital difference between it and the subfamily Muricine. The 
operculum in the Purpuwrine has a lateral nucleus instead of a 
subterminal one, but beyond this there are no essential differ- 
ences. The shell of the purpuras is generally heavy and solid, 
being adapted to a life among rocks which are exposed to the 
beating of the surf. There is a lack of that extravagant 
sculptural design so characteristic of the true murices, most of 
the purpuras being comparatively smooth, in order, no doubt, 
that they may offer as little resistance as possible to the rushing, 
seething waters of exposed rocky shores. 
The Purpurine, like some of the murices, when mutilated, 
exude a reddish-purple fluid. On account of this, the ancient 
Romans used to gather great quantities of certain Mediterranean 
forms belonging to these families, place them in large mortars, 
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