GASTEROPODS 381 



to Italy, where they are used in cameo-cutting 1 . It is owing to the fact 

 that the substance of these shells is deposited in layers of different colors 

 that they are available for this purpose. There are about fifty species 

 of helmet-shells, the one most valued for cameo-cutting being known 

 as the black helmet, C. Madagascar ensis. 



C. testicuhis. A species found outside of the West Indies only at 

 Key West and at Hatteras, where the Gulf Stream has brought so many 

 West Indian forms, and left them at the point where it takes its oblique 

 course away from the shore. This pretty species is smaller than the 

 others just described. It has a low, depressed spire ; longitudinal ribs 

 crossing wide, flat revolving ribs; a long, narrow aperture; and a 

 reflexed and thickened outer lip, also toothed. The columella is thick- 

 ened and ribbed. The anterior canal is recurved over the back of the 

 shell, as is usual in the genus. The color is bluish, with dark spots. 

 There are square black spots on the reflexed lip; the aperture is pink, 

 and the teeth and columellar ribs white. This species is exceedingly 

 common at Nassau, and plays havoc with the more slowly moving 

 bivalves, which it devours. (Plate LXXI.) 



C. inflata. Perhaps the commonest species of Cassis on our coast. 

 It is reported to be common at Beaufort, South Cai-olina, yet it is not so 

 frequently met with out of the West Indies as some earlier collectors 

 would have us believe. Beach-worn specimens, however, are not 

 unusual all along the Florida coast. It attains a size of from three to 

 four inches, and is a rounded, globose, ventricose shell, with a higher spire 

 than is usual in this genus. The surface is -almost smooth, the series of 

 revolving ribs being scarcely raised on the body-whorl. The lip is 

 thickened and reflexed, with prominent lamelliform teeth which continue 

 as internal ribs. The lower portion of the columella is calloused and 

 roughly granulated. The color is bluish-white, glazed, with large square 

 brown spots. The region of the aperture is pure white. The collector 

 should not remain content with a specimen or two of the poor beach- worn 

 shells of this species. In general, this advice applies to the collection of 

 all specimens. One can_get no idea of the sculpturing and painting of 

 shells from dead and worn specimens. It is quality rather than quantity 

 that makes an interesting cabinet. (Plate LXXI.) 



FAMILY MUBICIDJE 

 SUBFAMILY MTJBICINJE 



It seems like making a long leap to pass suddenly from the 

 Cassididce to the Muricidce. In the natural biological order, as it 

 appears in our present state of knowledge, a host of families and 

 genera intervene between these two. But they are omitted here, 

 either because they do not conspicuously occur upon our own 

 shores, or because they are free-swimming pelagic mollusks, 

 which live only far out at sea and rarely are found on the beaches. 

 The family Muricidce is an exceedingly large one, including a be- 



