450 
MOLLUSCA. VENERIDJE. 
Venus. 
2. V. plana . — llather depressed, subcordate, slightly angular towards the 
posterior side ; surface smooth ; edge entire. — Sower. Min. Conch, t. xx., low- 
er figures — Green Sand. 
3. V. incrassata — Orbicular, oblique, subdepressed, smooth ; posterior slope 
straightish ; lunule large, obscure ; edge entire ; a conical tooth under the 
iunule — Sower, Min. Conch, t. civ. f. 1, 2 . — London Clay. 
4. V. gibbosa — Orbicular, gibbous, with many transverse rugoe ; lunule 
large and short ; edge subcrenulated ; hinge rather large. — Sower. Min. Conch, 
t. civ. f. 3, 4 — Crag. 
5. V. turgida — Orbicular, gibbose, with concentric ridges ; valves thick, 
with tumid crenulated edges Soiver. Min. Conch, t. cclvi. — Crag. 
G. V. varicosa. — Subglobose, with projecting beaks, transversely furrowed, 
two longitudinal varicose ridges within each valve. An obscure cast. — Sower<> 
Min. Conch, t. ccxcvi. f. 1, 2 — Oolite. 
7. V. transversa — Transversely ovate, elongated, gibbose; nearly smooth ; 
anterior side small, rather pointed ; shell thin.— Aower. Min. Conch, t. ccccxxxii. 
f. 1 — London Clay. 
8. V. rotundata. — Obovate, gibbose ; marked with numerous, minute, trans- 
verse striae — .{Brander.^ f. 91.) — V. lineolata^ Sower. Min. Conch, t. ccccxxii. 
f. 2 . — London Clay. 
9. V. elegans — Ovate, convex, transversely sulcated ; lunette ovate ; the 
spaces betw'een the sulci rounded and shining — {V. gallina.^ Brander.^ f. 90.) 
— Sower. Min. Conch, t. ccccxxii. f. 3 . — London Clay. 
10. V. pectinifera . — Transversely oblong ; carinated ; surface longitudinally 
sulcated, and supporting a few erect lamellae, commencing at the keel ; pos- 
terior side smooth, truncated. — Sower. Min. Conch, t. ccccxxii. f. 4 . — London 
Clay. 
11. V. caperata. — Orbicular, rather depressed, covered with small, rounded 
concentric ridges; lunette cordiform, inconspicuous — Sower. Min. Conch, 
t. Dxviii. f. 1 . — Green Sand. 
12. Y . parva — Transversely obovate, rather convex, smooth; lunette nar- 
row. — Sower. Min. Conch, t. nxviii. f. 4, 5, 6. — Green Sand. 
13. V. (malts — Sower. Min. Conch, t. nlxvii. f. 12. 
14. Y.Faba — 3. 
15. V. Ringmeriensis. — Suborbicular, with numerous, transverse concentric 
striae, beaks incurved, approximate ; margin entire. A cast. — Mant. Geol. 
126. t. XXV. f b.—Grey Chalk Marl. 
Mr Sowerby has described two shells connected with this group, under a 
Genus which he terms Thetis, with the following character : “ An equi- 
valved, subequilateral bivalve ; more or less orbicular, and convex ; ligament 
marginal ; three or four small acuminated teeth about the hinge ; the line 
of attachment of the mantle ? has a deep sinus extending nearly to the beak ; 
muscular impressions rounded, small, distant from the hinge.” 
IQ. Thetis major. — Convex, orbicular; posterior edge rather angular ; beaks 
small. — Sower. Min. Conch, t. Dxiii. f. 1-4. — Green Sand. 
17* Thetis minor. — Gibbose, wider than long ; posterior edge rounded. Ve- 
nus, No. 12 — Mant. Geol. Suss, Sower. Min. Conch, t. nxiii. f. 5, 6.— r 
In Green Sand. 
