20 
valves thirteen, those on the dorsal valve in transverse 
rows, the three lower valves on each side’ to which the 
peduncle is fixed, are very small, the two next larger, 
the superior one the largesi, running a little oblique 
to the rest, and is pointed at the top; the dorsal valve 
is compressed, the edge rounded at the base, and run- 
ning into a sharp process about half-way up, from 
whence it turns in a diagonal line to cover the edge of 
the two superior valves: the upper part truncated ob- 
liquely to the front. Sandwich and Plymouth, rare. 
P. Cornucopia. Leach.—Lam. |.—Reeve. t. 14. 
f. \.—Pentarepas P. Bl. t. 84. f. 3.—Lepas. Pol- 
LiciPEs. Gmel, 3213.—Ch. f. 851. 2.—Arg. t. 26. f. 
D.—Wood. G. C. p. 60. t. 10, f. 2.—Knorr. 5. t. 
13. f. 7.—D. p. 29.—Mont. Sup. p. 6. t. 28. f. 5.— 
Turt D. p. 74.—Compressed, erect, solid, eight prin- 
cipal smooth convex white valves, besides numerous 
irregular small] ones environing the base: four larger 
valves obtusely pointed above ; membrane dark ; pedi- 
cle coriaceous, bluish as‘1-colored and shagreened. 
0,89. without the pedicle. Rather doubtful, very rare. 
Genus CINERAS. 
Body pedunculate, entirely enveloped in a thick mem- 
branaceous integument, with a large anterior opening 
B 
