The Murex Shells. Rock Shells 



mens on the west coast of Africa. They reach eight inches in 



length. 



Sub-genus CEROSTOMA, Com. 



Operculum with nucleus lateral; varices, three, wing-like; 

 aperture toothed inside lip, usually with one large tooth near base. 

 Much like Pteronotus. 



The Three-winged Murex (M. trialatus, Sby.) is the prize 

 of the collector in Southern California. It is taken by dredging 

 off San Pedro and San Diego. Three flaring, thin, often reflexed 

 wings adorn its spire; its pale surface is banded between the 

 varices with dark brown. The lip tooth is wanting. Length, 

 2 to 3 inches. 



The Leaf Murex (Af. foliatus, Martyn) is white, with chest- 

 nut bands, and a pronounced tooth on the lip, which distinguishes 

 it from M. trialatus. Length 2 to 3 inches. 



Habitat. — Rocky coasts. Sitka to Santa Barbara, Cal. 



Nuttall's Murex (M. Nuttallii, Conr.) is whitish, or 

 brown, banded with white. The six varices are thick, frilled rolls 

 crossed by fine spiral striae. The lip has a row of teeth within 

 the aperture, and one large tooth pointing down and outward. 

 Length, ij to 2 inches. 



Habitat. — California. 



The One-horned Murex (M. monoceras, Sby.) has fewer 

 and larger lip teeth, more tuberculated revolving ribs, less frilling 

 of the varices, lighter colour and a pink interior. Length, i J inches. 



Habitat. — Lower California. 



The Festive Murex (M. festivus, Hds.) is a familiar shell to 

 collectors in Southern California. I picked them alive from the 

 muddy rocks exposed at low tide along the breakwater in San 

 Pedro Bay. Dingy brownish white and coated with foreign 

 matters they scarcely show the fine brown spiral strias that 

 cover the surface. The thick whorls bear three ridge-like, crested 

 varices, which are bent backward. The small oval aperture is 

 closed by a horny operculum. The canal forms a short tube 

 that bends back at the tip. Length, i^ to 2i inches. 



Habitat. — Southern California. 



Sub-genus OCINEBRA, Leach 



Spire elevated; canal more or less closed; varices numerous, 

 leaf-like, sometimes spinose. 



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