CASSIDIDJB. 201 



the edge finished with oil-stone. It is next cemented to a block 

 of wood, which serves as a handle to be grasped by the artist 

 while tracing out with a pencil the figure to be cut on the shell. 



The pencil-mark is followed by a sharp point, which scratches 

 the desired outline, and this again by delicate tools of steel 

 wire, flattened at the end and hardened, and by files and 

 gravers, for the removal of the superfluous portions of the 

 white enamel. A common darning-needle, fixed in a wooden 

 handle, forms a useful tool in this very minute and delicate 

 species of carving. The careful manipulation necessar}^ in this 

 work can only be acquired by experience ; the general shape 

 must first be wrought, care being taken to leave ever^^ projection 

 rather in excess, to be gradually reduced as the details and 

 finish of the work are approached. To render the high parts 

 more distinct during the process of carving they are slightly 

 marked in black. — Simmonds, Commercial Products of the Sea, 212. 



SBMiCAssis, Klein. (Cassidea, Swn. ) Shell oval, with revolving 

 ribs, spire moderate, sharp. G. canaliculatus, Brug. (Ixii, 23). 



PHALiUM, Link. (Bezoardica, Schum., 1817.) Shell varicose, 

 angular behind, oval, with moderate spire ; outer lip usually 

 strongly dentated in front. G. undatus, Mart. (Ixii, 24). 



CASMARiA, H. and A. Adams. Shell smooth, whorls simple or 

 subplicate, spire moderate; inner lip smooth, callous, outer lip 

 margined, smooth or slightly crenulated on the inner edge. G. 

 pyrum, Lam. (Ixii, 25). 



CASSIDEA, Link. (C3^pr8ecassis, Stutchb.) Shell ovate, spire 

 short; mouth narrow, subcanaliculate behind, columella plicate 

 its entire length; varices none or obsolete. No operculum. 

 The mantle-margins are reflected over the lips of the shell. G. 

 testiculus, Linn. (Ixii, 26). 



' LEVENIA, Grray. Shell oval, subcylindrical, spire short, conic ; 

 aperture narrow, contracted in the middle, columellar lip plicate 

 throughout, outer lip without external rib, inflected and dentate. 

 Operculum narrow. G. coarctatus^ Gray (Ixii, 27). 



Cassidaria, Lam. 



Etym. — Gassida, a helmet. 



Syn. — Galeodea, H. and A. Adams. Morio, Montf. 



Distr. — 5 sp. Mediterranean. Fossil, 30 sp. Cretaceous, 

 Eocene — ; Europe, West Indies. G. echinophora, Linn. (Ixii, 29). 



Shell nodulous, ovate or oval-oblong, somewhat attenuated in 

 front to a short, subascending canal ; inner lip more or less 

 spread over the body-whorl, tuberculated or plicate, outer lip 

 reflected, ribbed and plicate within. Operculum corneous, ovate, 

 summit median and marginal, outer edge sinuous. 



SCONSIA, Gray. Shell oval-fusiform, with revolving strise and 

 a single longitudinal varix ; aperture long, canal very short, and 



14 



