Fam. 67.] NATUKAL HISTOKY SOCIETY. 147 



A. Umbilicus more or less covered with brown callus 2. 



. * Shell under 20 long. (B.) 



B. Umbilicus open 5, 



B. Umbilicus more or less covered with white callus. (C) 



O. Under 10 long , J. 



G. Over 10 long 4. 



1. Natica pusilla, Say. Shell thin, saboval ; callus pressed later- 

 ally into the umbilicus, whitish ; umbilicus consisting of an 

 arcuated, linear, vertical aperture. Cinereous or rufous, with 

 sometimes, one or two obsolete, revolving bands. L. 6 ; D. 5 ; 

 An. 100° ; Wh. 3 ; Ap. f .— Mass. and south. Not rare. 



2. Natiea (Neverita) duplicata, Say. (Figs. 31 and 39). Shell 

 solid, subglobose ; whorls convexly flattened above ; aperture 

 oval, oblique ; umbilicus irregular, with a deep furrow, and 

 almost covered by a thick callus. Color ashen-gray, deep chest- 

 nut-brown within ; callus of the same color. L. 50 ; D. 50 ; An. 

 100° ; Wh. 5 ; Ap. f . — Mass. and south. Abundant south of 

 Cape Cod. 



3. Natica (Lunatia) Aeros, Say. (Fig. 38, young shell). Shell 

 large, thick, globular ovate; whorls convex ; aperture oval, dark 

 reddish-brown, or tinged with yellowish ; the callus reflected 

 over a small portion of the larger, patulous, and coarsely wrin- 

 kled umbilicus ; the young shell is sometimes marked by three 

 revolving series of parallel, oblong, brown spots, 12 or 14 in each 

 row. L. 60; D. 50; An. 120°; Wh. 5; Ap. f.— Whole extent. 

 Common. 



4. ]\atica (Limatia) Gr (Enlandica, Mo\. Shell suboval, smooth, 

 glossy, or with faint lines of growth and revolving lines ; suture 

 distinct and deep ; lip sharp, callus pressed laterally into the 

 umbilicus, leaving a narrow, curved, linear opening. Epidermis 

 ash-colored, bluish-white beneath. L. 12J ; D. 11; An. 110°; 

 Wh. 4 ; Ap. f . — Mass. and north. 



5. Natica {Lunatia) immaculata, Tot. Shell small, solid, sub- 

 oval; apex short and pointed, suture not impressed; aperture 

 narrow, somewhat acutely curved at base ; umbilicus rounded 

 and deep, but little covered by the callus which is not very large, 

 but forms a deposit under the upper part of the lip, and causes 

 a white spiral line to show just below the suture. Epidermis 

 thin, greenish-yellow, milk-white beneath. L. 7; D. 5 J ; An. 

 90° ; Wh. 5 ; Ap. f .— New York and north. 



