The Top Shells and Dolphin Shells 



In bad weather they sink to the bottom. Fragments are picked 

 up on the beach, but rarely a perfect shell. The whorls are 

 yellowish, ornamented with raised brown dots in parallel rows; 

 the depressions between the whorls and the area about the axis 

 are shaded with purple. The exterior is almost as beautiful 

 as the pearly lining. Height, i inch. 



Habitat. — California. 



The largest American species is C. canaliculatum, Martyn, 

 an inch and a half high. It is conical; its revolving ribs sharp- 

 edged and separated by spiral canals, which, however, are not 

 purple. The ribs are pale yellow or ashy, the depressions 

 brownish. 



Habitat. — Pacific coast. 



The Blue Top Shell (C. costatum, Martyn) is the abundant 

 species along the northern Pacific coast. It is conical, with a 

 sharp apex, rounded whorls and flattened base. The whorls 

 are ornamented by parallel yellow riblets separated by brown 

 depressions. The aperture is round and beautifully pearly; 

 the columella simple. 



This shore-dwelling species has a heavy shell. A dilute 

 acid bath and a scrubbing removes the outer layer and exposes 

 the blue pearl that forms the shell substance. The living mollusks 

 crawl on rock surfaces exposed by the tide, but remain in the 

 dark if possible. Length, f inch. 



Habitat. — California northward. 



C. gemmulatum, Cpr., is wound with strings of granules, 

 each whorl bearing two principal rows, and many small ones. 

 The gray surface is streaked with dark brown from the apex 

 downward. Height, J inch. 



Habitat. — Southern California. 



Several recently named species have been discovered by 

 collectors dredging in deep water off the California coast. All 

 are easily recognisable as top shells by their characteristic form. 



The Pearly Top Shell (C.occidentale, Migh. and Ads.) of the 

 Maine coast is strongly ribbed, with a row of white dots ornament- 

 ing the pearly surface of the upper half of each whorl. It is 

 but half an inch long, and is only obtained by dredging in gravel 

 off shore. 



The Top Shell of Florida and the Carolina coast is C. euglyp- 

 tum, A. Ads., a regular pyramid, f inch high, with a solid 



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