Cardium. 
CONCHIFERA. 
199 
Transversely sub-quadrangular, with a keel running from 
the beak at the posterior side to the base ; surface longitu¬ 
dinally furrowed, with three or four erect transverse lamellae, 
which are pectinated upon their lower sides; anterior side 
smooth and truncated. 
The London Clay, Barton. 
10. Cypricardta Deltoidea. —The Deltoidal, Cypricar- 
dia, pi. LXXXI. fig. 7. 
C. deltoidea. Phillips, Pal. Fos. p. 37, pi. 17, fig. 59. 
Portlock, Geo. Rep. pi. 3(5, fig- 7. 
Ovate, rbomboidal, compressed; anterior side rounded; 
posterior side obliquely truncated below, with an oblique 
ridge from the beaks to the base ; beaks obtuse, nearly cen¬ 
tral ; base rounded; surface smooth. 
The Devonian Shales, Petherwin, Cornwall, and the Carboni¬ 
ferous Limestone, Tyrone, Ireland. 
11. Cypricardia tricostata. —Tho Three-ribbed Cypri- 
cardia, pi. LXXXI. fig. 13. 
C. tricostata . Portlock, Geo. Rep. p. 411, pi, 34, fig. 17. 
Much elongated transversely, moderately inflated ; hinge¬ 
line lengthened, and nearly straight; anterior side short and 
rounded; posterior side lengthened, with a pretty strong 
diagonal ridge from the beak to the margin ; a little above 
this are two other ridges, and one running parallel, and close 
to tho hinge-line; surface with irregular concentric stria?. 
The Carboniferous Limestono, Caruteel, Tyrone, and 
Drumkecran, Fermanagh, Ireland. 
Captain Portlock considers this species as highly characteristic of the 
iron-gray Limestone in which it occurs. 
Genus XXII.—CARDIUM.— Linnaeus. 
Shell equivalve, nearly equilateral, and more or less gaping 
posteriorly ; generally with strong ribs radiating from the um- 
bones or beaks to the margins; inside of the lips creuulated 
or dentated, corresponding in sizo to tho ribs, two approximate 
oblique cardinal teeth in each valve, locking into each other 
cross-ways, and with two remote, lateral teeth in both valves; 
two lateral, distant, muscular impressions in each valve; man¬ 
tle impressions entire ; ligament external. 
1 . Cardium striatum. — The Striated Cardium, pi. 
LXXXI. fig. 21. 
C. (?) striatum. Sowerby, Silur. Syst. pt. II. p. G14, pi. G. f. 2. 
Shell sub-orbicular, convex, beaks prominent; surface co¬ 
vered with numerous longitudinal, divergent stria?; length an 
inch and seven-eighths; breadth an inch and five-eighths. 
In the Aymestry Limestone, near Shelderton, in Lower 
Ludlow, and also at Aymestry. 
Murchison mentions a variety of this species larger than the above, 
more oblique in its form, and provided with more distant and deeper 
strite; it is found in the landslip, in Wheeler Vallets Wood, north flank 
of Urindgwood Cbacc. 
2. Cardium gentianum.— Gent’s Cardium, pi. LXXX, f. 1. 
Cardita tuberculata. Sowerby, II. p. 97. pi. 143. 
Ileart-sbaped, valves equal, laterally compressed, and longi¬ 
tudinally sub-carinated, one side somewhat lobated, tho other 
nearly flat; beaks much incurved; surface with numerous 
longitudinal, tuberculated ribs, placed in sets of three or four, 
with longer and more conspicuous ones intervening. 
U'pper Greensand, Devizes, and Lyme Regis, Dorset. 
3. Cardium IIillanum. —Hill’s Cardium, pi. LXXXII. 
fig. 3. 
C. IIillanum. Sowerby, I. p. 41, pi. 14, upper fig. 
Nearly circular, a very little wider than long, and slightly 
oblique; somewhatgibbose, with longitudinal furrows, which 
occupy about a fourth of its breadth on the anterior side ; whole 
surface with uumerous concentric striae, the interstices between 
which are smooth. 
Greensand, Blackdown and Haldown. 
4. Cardium Plumstediense. —Tho Plumsted Cardium, pi. 
LXXXI. fig. 22. 
G. Plumstedianum. Sowerby, I. p. 42, pi. 14, right and 
left hand upper figures. 
Sub-cordate, smooth, anterior side longitudinally furrowed, 
tho serrations on the edge of the shell being rather acute, with 
transverse, irregular, slightly defined lines of growth, which 
cover but a fifth of the surface. 
Plastic Clay, Plumsted and Upnor. 
5. Cardium nitens. —The Shining Cardium, pi. LXXXII. 
figs. G, 7. 
C. nitens. Sowerby, I. p. 43, pi. 14, lower right hand 
figures. 
Rather round, anterior side a little produced; smooth and 
shining ; surface covered with faint, punctated lines of growth, 
which are most distinct at the anterior side; near the base 
longitudinally striated. 
The London Clay, Ilighgate and Nunoham. 
6. Cardium angustatum. —The Narrowed Cardium, pi. 
LXXXII. fig. 8. 
C. angustatum. Sowerby, III. p. 149, pi. 283, fig. 2. 
Transversely elongated, its length equalling two-thirds of its 
breadth ; thin, somewhat depressed ; anterior side truncated ; 
posterior side rounded; surface with twenty-seven longitudinal 
ribs; margin toothed. 
Red Crag, Sutton ; and Aldcrton, near Woodbridge. 
7. Cardium edulinum. —The Small Edible Cardium, pi. 
LXXXII. fig. 13. 
C. edulina. Sowerby, III. p. 149, pi. 283, fig. 3. 
Thick, almost orbicular ; convex, and slightly oblique ; an¬ 
terior side a little truncated ; posterior side somewhat pro¬ 
duced ; surface covered with eighteen rugoso longitudinal ribs. 
Differs from C. edule in tho form of the anterior side, which is less 
wedge-shaped, and is somewhat shorter. 
The Red Crag, Sutton, and tho Coralline Crag, Ramshot. 
8. Cardium Parkinsoni. — Parkinson's Cardium, pi. 
LXXXI. fig. 20. 
C. Parkinsoni. Sowerby, I. p. 10.5, pi. 49. 
Gibbose, somewhat oblique; posterior side a little parallel; 
with thirty-eight to forty longitudinal ribs, with transverse 
slight elevations on each, which are most prominent towards 
the margin. 
Differs from C. edule in its more delicate form, and in being less acute 
at the posterior side. 
Red Crag, Walton. 
9. Cardium proboscideum. —The Produced Cardium, pi. 
LXXXI. fig. 19. 
C. j)roboscideum. Sowerby, II. p. 127, pi. 15G, fig. 1. 
Gibbose, sub-orbicular; anterior side nearly parallel; sur¬ 
face with about twenty slightly elevated longitudinal ribs, each 
