14 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
Genus PURPURA Martyn, 1784 
Shell triangular, varices wing-like; aperture elongate-ovate. Canal 
moderately long, usually closed in adult specimens; outer lip with a pro¬ 
duced tooth near the base. (Tryon, Manual of CoHchology .) 
This is the description of the subgenus Cerostoma (Conrad). Purpura 
Martyn is the first binominal use of the name, used by the ancients collo¬ 
quially to indicate the muricoid shells from which the Tyrian purple was 
derived. In harmony with this tradition it is applied by Martyn to a shell 
which Linnaeus would have called Murex, and which has been usually 
known as Cerostoma foliatum Martyn, after Carpenter. This is Martyn’s 
only species of Purpura in Volumes I and II, and hence the type. In 1798 
Bolten adopted the same view, and began his list of Purpuras with the 
group of Murex trunculus. There seems to be no doubt that, if any of 
Martyn’s names are valid, Purpura foliata must typify the group bearing 
the ancient designation. (Dali.) 
Type. Purpura foliata Martyn, 1784. 
Distribution. North Pacific, Japan, Bering Straits. 
Purpura foliata Martyn, 1784 
Figures of Nondescript Shells; Table 2, PI. 66. 
Shell ovately oblong, spire rather short; whorls transversely ribbed, 
ribs small, compressed, somewhat distant, interstices smooth; three-vari¬ 
cose, varices thin, erectly foliated, whitish, banded with chestnut-brown; 
aperture small, columella lip simple, outer lip denticulated, armed at the 
lower part with a small flattened tooth; canal short, flatly compressed, 
closed. ( Conchologica I conic a .) 
Length, 85; diameter, 45 mm. (Oldroyd.) 
Type in Museum White. Type locality, Sitka, Alaska. 
Range. Sitka, Alaska, to San Diego, California. 
Purpura nuttallii Conrad, 1837 
Journal of the Philadelphia Academy of Natural Sciences, 7 :264; PI. 20, fig. 22. 
Shell fusiform, whorls with three prominent obtuse varices, carinated 
on the back, and lamellar at base; aperture elliptical; submargin of the 
labrum toothed; channel of the beak concealed; color brown, with a white 
band on each whorl; within, white. (Conrad.) 
Length, 1.5-2 in. (Tryon, Manual of Conchology.) 
1 ype in Philadelphia Academy of Sciences. Type locality, Santa 
Barbara, California. 
Range. Monterey, California, to Scammons Lagoon, Lower California. 
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