148 JOURNAL OF THE NEW JERSEY 



2. SiGARETUs, Lam. 



Shell ear-shaped, witli a minute spire and very large aperturer; 

 operculum minute, horny, subspiral. 



Animal with a large mantle, partly or entirely covering the 

 shell ; anterior foot-lobe, used in burrowing, very large. 



L Sigaretus perspectivm^ Say. Shell ovate, elongated, depressed ; 

 surface with numerous, impressed, slightly undulating lines, 

 crossed by revolving stria? which disappear beneath; aperture 

 more than f the entire area of the shell; suture distinct, but 

 not deep. Milk-white, sometimes tinged with brown; smooth, 

 j)olished, and faintly iridescent. L. o7 ; D. 30; An. 140°; Wh. 

 3 ; Ap. |. 



Family 68. ACM/EID/E. 



Shell wholly external, dish-shaped, with apex directed forward. 

 Animal with eyes, and a plumose, external gill on the neck. 

 1. AcM.EA, Esck. 



Shell solid, patelliform. Animal with a frilled muzzle pro- 

 duced at the lower front corners into two tubercles. 



L Acmcxa testucUnalis, Mul. (Fig. 42). Shell oblong, oval, 

 conical, surface finely checkered by the minute, radiating and 

 encircling lines; margin entire, sharp. Whitish or greenish, often 

 mottled with brownish. L. 20-35 ; W. 12-20 ; Height 7-12.— 

 New England. On rocks. Common north. 



Var. Alveus, Con. Shell smaller, oblong, twice as long as wide, 

 with nearly parallel sides. — Same region. On eel-grass. 

 Family 69. TROCHID/E. 



Sliell usually conical, with flattened base, brilliantly pearly 

 inside ; operculum horny, multispiral. Animal with a short 

 muzzle; eyes pedunculated at the outer base of long, slendei- 

 tentacles ; head and sides ornamented with fringed lobes, and 

 tentacular filaments. Feeding on sea-w-eeds. 

 1. Margareta, Leach. 



Shell usually thin, globular-conical, umbilicated ; aperture 

 rounded, pearly ; lip sharp, smooth. Many species are found 

 in deep water. The following is in rather shallow water. 



1. Margareta obscura, Cout. Shell solid, low-conical ; whorls 

 convex, and rendered angular near the middle by a prominent, 

 revolving ridge ; often one or two additional and less prominent 



