Count) LA.. 
CON CIII FEU A. 
221 
flattish, wedge-shaped, gaping at the anterior end ; hinge of 
the left valve with ail elevated, transversely dilated tooth— 
that of the right valve with a concave tooth, and a small 
denticlo behind it, destitute of lateral teeth ; two small muscu¬ 
lar impressions in each valve ; pallial impression with a large, 
tongue-shaped sinus, emanating from the anterior side, and 
reaching nearly the middle of the valves; ligament external. 
1. Sphenia Binghami. —Bingham's Sphenia, pi. XC. figs. 
44, 45. 
S. Binghami. Brown, Ill. Rec. Conch, p. 104, pi. 42, figs- 
17, 18. and 22. 
Transversely oblong ovato ; anterior side short and rounded ; 
posteriorly truncated; beaks rather prominent, and not quite 
opposite; surface smooth. 
The Coral Crag, Sutton. 
2. Sphenia Swainsoni. —Swainson’s Sphenia, pi. XC. f. 37. 
S. Swainsoni. Brown, Ill. Rec. Conch. Brit. p. 104, pi. 
42, figs. 1G, 23, 24. 
Transversely oblong oval, wedge-shaped; anteriorly rounded 
and short; posteriorly elongated and truncate ; a concave tooth 
lying horizontally and pointing inwards; surface smooth. 
The Pleistocene Marine Formation, Bute. 
Genus XLV1II.—SAXICAVA .—Lamarck. 
Shell transverse, irregular in form, generally oblong, inequi¬ 
lateral, sub-equivalve, gaping anteriorly ; ligament exterior; 
two lateral muscular impressions in each valve; pallial im¬ 
pression interrupted, but not sinuated; hinge in the young 
condition with sometimes two or three minute, obtuse, mostly 
indistinct cardinal teeth, which become obsolete in the adult. 
1. Saxicava eugosa. —The Rugged Saxicava, pi. XC. fig. 
17. 
S. rugosa . Sowerby, V. p. 101, pi. 466. Brown, Ill. Rec. 
Conch. Brit. p. 103, pi. 47, fig. 1. 
Transversely oblong ovate, gaping at one side ; beaks small, 
obtuse, and placed near the anterior side ; posterior side sub- 
truncated ; surface with irregular, rugged, concentric wrinkles. 
The Pleistocene Marine Formation, Dalmuir and Bute, 
Mammiferous Crag, Thompe, and the Red and Coral Crags, 
Sutton. 
Genus XLIX.—AGINA.— Turton. 
Shell transverse, oval, equivalve, inequilateral, open at the 
anterior side ; hinge with a single erect, conic, penetrating 
cardinal tooth in each valve, destitute of lateral teeth; liga¬ 
ment external. 
1. Agina purpura. —The Purple Agina, pi. XC. fs. 2G, 27- 
A. purpura . Turton, Brit. Biv. p. 55, pi. 4, fig. 9. 
Transversely oval; posterior side obliquely truncated; 
beaks prominent, closo to the shorter anterior side; surface 
with irregular, transverse stria?; length one-eighth of an inch, 
breadth one-quarter. 
The Coral Crag, Sutton. 
Tribe III.—CORBULACEA. 
Shells inequivalve, the ligament interior. 
Genus L.—PAN DO R A .— Bruguiere . 
Shell free, thin, internally pearlaceous, inequivalve, trans¬ 
verse, inequilateral, the anterior side the longer, sub-rostrated, 
and slightly gaping at its extremity; one valve flat, with two 
internal anterior ribs, and with its anterior margin turned 
downwards, provided with a single, oblong, obtuse, cardinal or 
hinge tooth, situate behind the ligament; the opposite valve 
concave and destitute of teeth, but furnished with an indistinct 
cicatrice on which the tooth of the flat valve rests when the 
shell is closed; in each valve are two distant, lateral, muscular 
impressions; ligament internal, its sides lodged in, and at¬ 
tached to an elongated cicatrice, which lies inclined to the an¬ 
terior sido of the valves; in some species the cicatrice is pro¬ 
duced into an elongated divergent lamina, stretching from the 
umbo towards the anterior side of the shell, and terminating 
near the inner side of the anterior muscular impression. 
1. Pandora margaritacea. —The Pearly Pandora, pi. XC. 
figs. 23, 24, 25. 
P. margaritacea. Turton, Brit. Biv. p. 40, pi. 3, figs. 11-14. 
Transversely oblong; arcuated; one valve nearly flat, the 
other moderately convex ; beaks situate near the anterior side, 
which is rounded ; surface rather smooth and pearly. 
The Red Crag, AValton Naze, and the Coral Crag, Sutton. 
Genus LI.—CORBULA.— Bruguiere. 
Shell inequivalve, one valve being generally small and flat¬ 
tened, the other largo and convex ; sub-equilateral, transverse, 
generally gibbose and close ; each valve usually furnished with 
a single conical, recurved, ascending, pointed tooth, at the side 
of which is a small concave depression, very deep in some 
species, which serves either for the reception of the ligament, 
or the tooth of the opposite valve; two distant, lateral, some¬ 
what irregular muscular impressions in each valve ; pallial 
impression posteriorly angulatcd, with a very small sinus; 
ligament internal, fixed to the tooth of the lossor valve, and 
inserted in the depression by the sido of the tooth in the larger 
valve. 
1. Corbula gallica. —The Maple-like Corbula, pi. XC. 
figs. 1, 2, 3. 
C. gallica. Lamarck, Ann. du Mus. VIII. p. 4GG, No. 1. 
Ib. An. Son. Vert. V. p. 497, No. 10. Ercy. Meth. pi. 230, 
fig. 5, a , /v, c. Deshayes, Coq. Foss. p. 49, pi. 7, figs. 1, 2, 3. 
Shell transversely ovate; the larger valve turgid ; the urn- 
bones with thin, transverse strim; beaks smooth; smaller 
valve with longitudinal remote rays. 
Found in the London Clay at Bracklesham. 
2. Corbula longirostrum. —The Long-beaked Corbula, 
pi. XCI. figs. G, 7. 
