FAMILY ANATINIDA — ANATINA. 235 
GENUS ANATINA. Lamarck. 
Animal having the mantle closed by a wide membranous plate, with a small rounded 
aperture on the antero-inferior portion, for the passage of a tongue-shaped foot. Two 
elongated tubes separated for some considerable distance from their extremities ; the infe- 
rior slightly longest. Branchie narrow, free, and pointed behind. Shell usually thin, 
sometimes translucent, fragile, ovate, rounded, nearly equivalve, inequilateral, gaping 
slightly at one or both extremities. Hinge with a prostrate spoon-shaped tooth in each 
valve, to receive the cartilage ; and a small ossiculum resting in front of the teeth, usually 
removed with the animal. 
ANATINA PAPYRACEA. 
PLATE XXXI. FIG. 300. 
(STATE COLLECTION.) 
Anatina papyracea, Say, Jour. Acad, Nat. Sc. Vol. 2, p. 314. 
A. id. fragilis? Torten, Amer. Jour. Sc. Vol. 28, p. 347, pl. 1. 
A. papyracea, GOULD, Invertebrata of Mass. p, 47, fig. 28. 
Description. Shell thin and fragile, ovate-rounded ; one valve more convex, and at the basal 
margin projecting a little beyond the other. Beaks not prominent, in the posterior third of 
the length of the shell: from the beaks to the posterior portion runs an elevated angular 
ridge ; shorter end narrowed and subtruncated, slightly gaping. Surface of the valves mi- 
nutely wrinkled. Tooth long, narrow and oblique, with an accessory process at the base. 
Ossiculum like two crescents fitting in front of the teeth. Color, white and pearly. 
Vertical axis, 0°5; transverse ditto, 0°6. 
This delicate shell, which is rare, occurs along our whole coast. It has been obtained by 
dredging at Newport, Rhode-Island, and from the stomachs of fishes on the coast of Massa- 
chusetts. 
30° 
