450 MOLLUSCA. VENERIDyE. Venus. 



2. V. plana. — Rather 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 

 lunule — Sower. Min. Conch, t. civ. f. 1, 2. — London Clay. 



4. V. gibbosa Orbicular, gibbous, with many transverse rugae; lunule 



large and short ; edge subcrenulated ; hinge rather large.— Sowr. Min. Conch, 

 t. civ. f. 3, 4 Crag. 



5. V. turgida Orbicular, gibbose, with concentric ridges ; valves thick, 



with tumid crenulated edges. — Sower. Min. Conch, t. cclvi. — Crag. 



0. 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. — Sower. Min. Conch, t. ccccxxxii. 

 f. 1. — London Clay. 



8. V. rotundata Obovate, gibbose ; marked with numerous, minute, trans- 

 verse striae — (Brander, f. 91.) — V. liueolata, Sower. Min. Conch, t. ccccxxii. 

 f. 2. — London Clay. 



9. V. elegans Ovate, convex, transversely sulcated ; lunette ovate ; the 



spaces between 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. 



1 1. V. caperata — Orbicular, rather depressed, covered with small, rounded 

 concentric ridges; lunette cordiform, inconspicuous. — Sower. Min. Conch, 

 t. Dxviii. f. 1. — Green Sand. 



12. V. parva. — Transversely obovate, rather convex, smooth ; lunette nar- 

 row. — Sower. Min. Conch, t. Dxviii. f. 4, 5, 6. — Green Sand. 



13. V. ovalis — Sower. Min. Conch, t. Dlxvii. f. 12. 



14. V. Faba 3. 



15. V. Ringnieriensis — Suborbicular, with numerous, transverse concentric 

 stria?, beaks incurved, approximate ; margin entire. A cast. — Mant. Geol. 

 120. t. xxv. f. 5 — 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 equl- 

 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." 



10. Tlielis major. — Convex, orbicular; posterior edge rather angular ; beaks 

 small. — Sower. Min. Conch, t. Dxiii. f. 1-4 Green Sand. 



17- Tlietis minor. — Gibbose, wider than long ; posterior edge rounded. Ve- 

 nus, No. 12 — Mant. Geol. Suss. 73.— Sower. Min. Conch, t. Dxiii. f. 5, 6.— 

 In Green Sand. 



