18 AMERICAN MARINE CONCHOLOGY. ' 
e 
Animal with a broad short muzzle; tentacles cylindrical, bear- 
ing the eyes on prominences near their bases, outside; foot short, 
angular in front; branchial plume single, long. 
Subgenus Arrhoges, Gabb. 
Am. Journ. Conch., iv. 145. 1868. 
Shell fusiform, anterior canal nearly obsolete, no posterior canal, 
outer lip expanded, simple. . 
1. A. occIDENTALIS, Beck. Fig. 125. 
Guérin, Mag. Zool., t. 72. 1836. 
Whorls eight to nine, convex, with numerous waving vertical 
folds and regular conspicuous revolving lines; lip expanded, with 
a blunt process above. Epidermis thick and dusky; beneath 
bluish-white. Length 2.25; width 1.5 inches. 
Maine, northwards. 
Family MURICIDAi. 
Animal with a broad foot ; eyes sessile on the tentacles, or at 
their base; branchial plumes two. Lingual ribbon long, linear. 
Teeth in three series (I:I-1) the central broad, the lateral versatile. 
Mantle inclosed, the margin producing varices at intervals across 
the shells, and extended in front, forming a straight, more or less 
elongated siphon. Foot simple in front. 
Synopsis of Genera. 
1. Not wmbilicated. Outer lip thickened. 
Lip without folds ; whorls with varices. 
Shell ornamented with three or more continuous longitudinal varices ; 
aperture rounded ; beak often very long ; canal partly closed ; operculum 
concentric ; nucleus sub-apical. Murex, Linn. 
Shell with two rows of continuous varices, one on each side. 
RANELLA, Lam. 
2. Not umbilicated.  Columellar lip with folds ; no varices. 
Shell fusiform, elongated ; not cancellated; whorls round or angular ; canal 
open; columellar lip tortuous with’ several oblique folds. Operculum 
claw-shaped. FAscroLaria, Lam. 
Shell cancellated ; aperture channelled in front; columella with several 
strong oblique folds ; no operculum. CANCELLARIA, Lam. 
3. Umbilicated. Shell spirally furrowed ; columella without folds. 
Thin, wmbilicated ; spirally furrowed; the ridges with epidermal fringes ; 
columella obliquely truncated ; operculum lamellar, nucleus external. 
Tricnorroris, Brod. 
