366 MARINE INVERTEBRATES 
able for their beauty and rarity, have been greatly prized by col- 
lectors. A single specimen of the now well-known S. pretiosa of 
China has been sold for two hundred dollars—a fancy price, indeed, 
for a shell which can now be bought for a dollar! There are 
over fifty species of Scala on the Atlantic coast, but most of them 
are either rare or belong to a zone of deeper water; there are, 
however, four or five species which are exceedingly common. 
S. lineata. A species which ranges from Hatteras to New 
England. It has about eight whorls, and is slightly brownish 
in color. The ribs are robust and not greatly elevated ; there 
are from seventeen to nineteen on the body-whorl. The shell 
is sometimes painted with a few revolving brownish lines. 
S. multistriata. The transverse ribs are much smaller but 
very numerous; the small spaces between them are 
marked with many fine revolving lines. Found 
from Cape Cod southward. . 
S. groenlandica. Essentially an arctic species, 
scata tine. Which has found its way down to the New England 
ata, coast. It is readily distinguished by the flattened, 
coarsely rounded, revolving ribs, which follow 
the volutions of the spire. Over them are the usual trans- 
verse heavy ribs peculiar to this genus. 
__S. angulata. The whorls touch one another only by the J 
ribs, of which there are nine to each volution. This species  geatamuttistri 
has a remarkably wide range, occurring from Cape ata, 
Cod to southern Florida. (Plate LX VIII.) 
_ These four species vary from one half of an inch to one inch 
in length. All of them are found on the beach after storms or 
may be dredged in shallow water near the shore. 
FAMILY NATICIDE 
This large and interesting family is well represented 
Scala groen- in the Atlantic waters of the United States, but its more 
“beautiful members live in the tropics. The New England 
and New Jersey species are dull in color, but offer much of interest 
to the collector and student. The foot is enormously large, and 
carries in front a great shield-like fleshy process, which curves back 
over the head of the animal and serves as a plow in pushing its way 
through the heavy wet sand of the beach. When the creature is 
thus seen extended in the act of crawling, one wonders how it is pos- 
sible for it to withdraw so great an amount of body into its shell; 
but if it is suddenly seized or irritated, it will quickly demon- 
J) 
