200 WEST AMERICAN SHEERS 
Another Purple, which lives in 
San Francisco Bay, but is more 
highly developed a few hundred 
miles to. the northward, is 
named Purpura crispata, Chem., the 
Wrinkled Purple, and a rather poor 
figure of a small specimen is shown 
in Figure 209. Specimens from Pu- 
get Sound are beautifully frilled 
and richly painted with brown 
bands. The shells are strong and heavy, and have 
an average length of an inch and a half to two 
inches. Some are nearly smooth, while others are 
extremely wrinkled. Though the smooth, white 
varieties are very plain in their appearance, some 
of the northern beauties, all frilled and banded as 
if to attract attention, are worthy of a place in any 
choice collection of handsome shells. 
Closely related to the Purples are the Unicorn- 
shells, a small group of mollusks which are al- 
most exclusively confined to the west coast of 
America. Their name refers to the fact that a 
little horn is developed on the edge of 
the outer lip, near the canal, as is well 
shown in Figure 210, Monoceros en- 
gonatum, Conr., the Angled Unicorn. 
These mollusks are found clinging to 
rocks, under a heavy growth of sea- 
weed. The shells themselves are al- 
most the same color as the stones to pea 
which they are attached. The name of this spe- 
cies is suggested from the fact that the whorls are 
~ 2 
Fig 209, x 3 
