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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. firoenlantlica. Essentially an arctic species, 

 which has found its way down to the New England 

 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 

 ribs, of which there are nine to each volution. This species 

 has a remarkably wide range, occurring from Cape 

 Cod to southern Florida. (Plate LXVI1L) 



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 NATICIDJE 



This large and interesting family is well represented 

 scaia 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- 



Scala multistri- 

 ata. 



