The Horn Shells 



further sculpture the surface. Chestnut dots and patches colour 

 the depression and the aperture. Sometimes the shells are 

 colourless. 



Habitat. — West Indies, Florida. 



The Dark Horn Shell (C. atratum, Born.) has a row of 

 small nodules in the suture, and a larger row on the keel of the 

 whorl, with fine strise between. A strong varix is opposite the 

 aperture. Colour, dark gray or chocolate; aperture bluish. 

 Length, i. to i J inches. 



Habitat. — ^^West Indies, Florida. 



C. muscarum, Say, has rounded, spirally ribbed whorls 

 crossed by longitudinal, finely knobbed, ridges. Small brown 

 dots cover the more depressed surfaces and often the ridges as 

 well. This is a slender species. Length, i inch. 



Habitat. — Bahamas, Florida. 



C. litteratum, Born., is a stouter shell, i to ij inches long, 

 its whorls bordered above with the strongest set of tubercles, 

 the depressed surfaces dotted and splashed with pale brown, 

 in a pattern resembling letters. 



Habitat. — West Indies, Florida. 



C. ferrugineum, Say, is two-thirds of an inch long, dark 

 with orange red tinge, spirally ridged and faintly knobbed, with 

 a dark aperture. 



Habitat. — South Carolina to Florida. 



C. laeve, Quoy, a smooth species, is the largest living mern- 

 ber of the family. It is white with many flattened whorls 

 forming a regular spire, except that the body whorl is slightly, 

 swollen. Length, 5 to 6 inches. 



Habitat. — Australia. 



Genus CERITHIDEA, Swains. 



This group is distinguished by the tree-dwellers and other 

 amphibious forms it contains. 



The Decollated Cerithidea, (C. decollata, Linn.), the type 

 of the genus, is a widely distributed species of robust character, 

 somewhat over an inch long. The apex is truncated, the rounded 

 whorls brown, sometimes with a white line at the suture, with 

 strong ridges and fine striie crossing all over the surface. These 

 mollusks live on swampy coasts of warm regions. They some- 



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