MARINE MOLLUSCA OP THE UNITED STATES. 19 



4. Not umbilicated. Shell pear-shaped ; fusiform ; outer lip thin; columella 



smooth. 



Pear-shaped ; spire short ; whorls angular above ; canal long, curved, open ; 

 operculum with apical nucleus. Stcotypus, Browne. 



Pyriform, light, ventricose, ribbed, and cancellated ; spire very short ; aper- 

 ture large ; columella simple ; canal straight, elongated ; outer lip thin, 

 entire. Ficus, Klein. 



Fusiform ; spire conical ; canal straight, long ; operculum ovate, curved ; 



nucleus apical. Fusus, Lamarck. 



Genus MTJREX, Linn. 



Syst. Nat., edit, x., 74G. 1758. 



The murices appear to form only one-third of a whorl annually, 



ending in a varix, hut some species form intermediate varices of 



less extent. There are over two hundred species, of world-wide 



distrihution. 



1. M. spinicostata, Yalenciennes. Fig. 17. 

 Kiener, Icon. Coq., 49, t. 41, f. 1. 

 Shell pear-shaped, sometimes ohlong, sometimes shorter and 

 ventricose; whorls hiangulated at the upper part, transversely 

 ridged and striated ; ridges minute, narrow, rather superficial ; six- 

 or-seven varicose veins armed with frond-like spines throughout ; 

 spines canaliculated, slightly curved, the basal, and those upon 

 the posterior angles, longer, sharp-pointed ; white, ridges reddish- 

 brown, stained here and there with small crescent-shaped spots of 

 a deeper color; interior of the aperture white, stained in places 

 with ruddy spots; canal rather . elongated ; sometimes shorter, 



recurved. 



Beaufort, North Carolina, to Gulf of Mexico. 



The North Carolina specimens are generally worn, evidently 

 dead shells. This is probably the most northern limit of the 

 species. 



Subgenus TJrosalpinx, Stimpson. 

 Am. Journ. Conch., i. 58. 1865. 

 Shell elongated, oval or short fusiform, longitudinally ribbed or 

 undulated and spirally striate'd ; aperture with a short canal- 

 Operculum semi-cordate, with the nucleus at the outer edge a lit- 

 tle below the middle. 



1. U. cinereus, Say. Fig. 42. 



Fusus. Journ. Phil. Acad., ii. 23G. 1821. 

 Buccinum plicosum, Menke, Synopsis, 2d edit. 59. 1830. 



Shell oval, fusiform, with five or six convex volutions crossed 



