The Horn Shells 



B. filosum, Gld., has about eight whorls, each lined with 

 four ridges, forming a graceful spire, ^ to § of an inch long. It is 

 thin, of horny texture, brownish to white, and found attached 

 to stones at low tide. Small hermit crabs often take possession 

 of the dead shells. Sitka to Monterey, Cal. 



B. nigrum, Totten, is i inch long, a chocolate-coloured 

 conical shell, cross-banded by spiral and longitudinal ridges, of 

 which the spiral only persist on the the base of the body whorl. 



Habitat. — New England to Florida. 



B. quadrifilatum, Cpr., has four raised lines on the convex 

 whorls of its graceful slender spire. Length, about J inch. 



Habitat. — Southern California. 



Sub-Genus CERITHIOPSIS, Forbes and Hanley 



Shell small, rather cylindrical, narrow, tubercled; whorls 

 numerous, narrowing toward base; aperture small; canal short, 

 straight; foot narrow. Inhabits northern and temperate seas. 



C. punctata, Linn., is a little brown shell, paler on the 

 ridges, which intersect, making the surface finely granulated. 

 The body whorl has a smooth concave base. Length, ^ to | inch. 



Habitat. — Massachusetts to Florida, West Indies. 



C. tubercularis, Montg., is the European horn shell found 

 also in Florida and on the west coast of North America. It is 

 half an inch long, however, in the New World form, twice as large 

 as the European type. It is a dark brown shell with three rows 

 of strong, regular tubercles. The sutures are well marked, 

 the apical whorls smooth. 



Habitat. — Europe, Vancouver Island to Southern California. 



C. purpurea, Cpr., has whorls in which the upper half is 

 dark brown, the lower half paler. Three series of nodules coil 

 from base to spire. Length, J to ^ inch. California. 



C. terebrans, C. B. Ads., has a narrow spire sculptured 

 with sharp spiral ridges, three on each whorl. Chocolate brown 

 solid colour is tinged with yellow. Length, | to § inch. 



Habitat. — Massachusetts to West Indies. 



Genus TRIFORIS, Desh. 



Shell spiral, elongated, granular, coiled to the left, whorls 

 numerous, aperture small with short canal. One hundred species. 



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