GASTROPODA 



551 



Cassis Lamarck. Shell solid, last whorl very large; canal short 



and bent backwards : 37 species, which are much used in cutting cameos. 



C. cameo Stimpson. Length 25 cm.; yellowish-white, tinged with 



yellowish-brown; lip and columella very broad, yellowish-cream color, 



with dark brown teeth and ridges: North 



Carolina to west Florida; West Indies. 



Fig. SG2 Fig. 863 



Fig. 862 — Dolium galea (Rogers). Fig. 863 — Cassis tuherosa (Rogers). 



C. tuberosa (L.) (Fig. 863). Length 20 cm.; surface crossed by 

 numerous fine grooves, both longitudinal and spiral; color yellow, with 

 brown blotches; lower whorl with 3 rows of protuberances: North 

 Carolina to west Florida; West Indies. 



Family 18. TRITONIDAE. 



Shell solid, conical or fusiform, with a high spire; surface rough; 

 outer lip thickened and turned in; operculum horny; aperture with a 

 canal: 150 species, in tropical seas. 



Triton Montfort. Tritons. Shell conical, with a crenulated outer 

 lip; whorls roughened by transverse and longitudinal 

 ridges : 100 species, in tropical seas ; the largest snails, the 

 shells being often used as trumpets. 



T. nodiferus Lamarck. Length 45 cm.; color brown 

 and white ; aperture red : Mediterranean Sea, East Atlan- 

 tic, Indian, and Pacific Oceans ; often used as a shepherd 's 

 horn or a war horn. 



T. tritonis (L.) (Fig. 864). Length up to 50 cm.; 

 color brown, white, and red; aperture red: Gulf of 

 Mexico; Indian Ocean. 



Subdivision 2. HETEROPODA. 



Pelagic, transparent prosobranchs in which the foot is a swimming 

 organ, and is made up of two parts, a compressed fin-like structure 



