CvTHEBEA. 



CONCHIFERA. 



205 



7. Venus gallina.— The Hen Venus, pi. LXXXIV. f. 10. 

 r. gallina. Brown, Ulust. Kec. Conch. Brit. &c. p. 89, pi. 



36, fig. II. 



Sub-triansrularly sub-coriliform ; moderately convex ; beaks 

 considerably turned to one side, and approximate ; lunette 

 oblong, and longitudinally striated ; surface with numerous 

 prominent, rounded, concentric ribs ; internal margin finely 

 erenatcd. 



Tlio Pleistocene Jlarine Formation, Ayr. 



8. Venus faba. — The Bean Venus, pi. LXXXIV. figg, 

 24, 25. 



V.fabn. Sowerby, VI. p. 129, pi. 5G7, fig. 3. 



Transversely obovate ; sub-compressed, flattened in the 

 middle ; beaks short ; lunette deep and lanceolate ; surface 

 with numerous fine concentric stria;, and inequidistant lines of 

 growth. 



Tho Lower Greensand, Parham and Blackdown. 



9. Venus elliptica. — The Elliptical Venus, pi. LXXXIII. 

 fig. 9. 



V. elliptica. Phillips, Geo. York, II. p. 20.9, pi. 5, fig. 7. 



Elliptical ; compressed ; posterior side a little narrowed ; 

 anterior side rounded ; surface with broad, concentric, shallow 

 furrows. 



The Carboniferous Limestone, Northumberland. 



10. Venus gibbosa. — The Inflated Venus, pi. LXXXIV. 

 fig. 6. 



F. gibbosa. Sowerby II. p. 126, pi. 155, figs. 3, 4. 



Orbicular ; gibbous ; hinge area very strong and broad ; an- 

 terior side a little truncated ; lunette large and short ; surface 

 with distant concentric lines of rrrowth ; inner edge with very 

 fine, hardly visible crenulations. 



The Crag, SuflTolk. 



11. Venus tuugida. — The Swollen Venus, pi. LXXXIV. 

 fig. 1. 



F. turgida. Sowerby, III. p. 101, pi. 25G. Dosina tur- 

 gidus. Wood. 



Orbicular ; gibbose ; hinge strong ; beaks large, rounded ; 

 surface with many distant, concentric ridges ; inside with a 

 series of inflated crenulations a little way from the margin, 

 which is much thickened ; substance of tho shell thick. 



The Red Crag, Sutton ; and tho Coral Crag, Ramshot. 



12. Venus pasciata. — The Banded Venus, pi. LXXXIII. 

 fig. 15. 



V.fatciata. Brown, Illust. Rec. Concb. Brit. p. 91, pi. 36, 

 fig. 10. 



Sub-triangular; sub-compressed; beaksnearly central, con- 

 siderably turned to one side, and acute, with a shallow ovate 

 lunette under them ; striated longitudinally ; that portion of the 

 valves rather concave ; cartilage side flat, with a large lanceo- 

 late depression ; surface with flat, transverse, broad, reflected 

 ribs. 



The Pleistocene Marine Formation, Inch Marnock, on the 

 Clyde ; the Jlammiferous Crag, Bramraerton ; and the Red 

 and Coral Crags, Sutton. 



13. Venusovata. — Tiic Ovate Venus, pi. LXXXIII. fig.l4. 

 V. ovahi. Brown, 111. Rec. Conch. Brit. p. 91, pi. -37, fig. 11. 

 Sub-triangular ; oblique ; sub-compressed ; beaks nearly 



central, straight, and slightly inflexed ; sides nearly equal ; sur- 

 face with rather strong, longitudinal, divergent ribs, crossed 



by fine transverse striae, producing a beautifully cancellated 

 appearance. 



The Pleistocene Marine Formation, Ireland ; and the Red 

 Crag, Sutton. 



14. Venus imdricata. — Tho Imbricated Venus, pi. 

 LXXXVII. fig. 20. 



Astarte imbricata. Sowerby, VI. p. 37, pi. 521, fig. 1. 



Cordiform ; orbicular; convex; lunette elongated and flat ; 

 tooth in tlio left valve under tho lunette rather small ; hinge- 

 line arcuated ; edge finely creuulated internally ; surface with 

 from nine to eleven transverse imbricated ribs. 



The Red Crag, Sutton ; and Coralline Crag, Ramshot. 



15. Venus parallela. — TheParallel Venus, pl.LXXXIII. 

 figs. 3, 4. 



y. parallela. Phillips, Geo. York, II. p. 209, pi. 5, fig. S. 



Transversely ovate, with sub-parallel sides ; back gently 

 sloping from the beaks, which are small and pointed ; lunette 

 lanceolate, and rather deep ; surface with delicate concentric 

 furro ivs. 



The Carboniferous Limestone, Bolland. 



Genus XXX.— CYTHEREA.— iamarc^-. 



Shell bivalve, equivalve, generally more or less equilateral, 

 or obtusely trigonal and transverse, or ovate ; smooth, or va- 

 riously striated ; with three or more short divergent cardinal 

 teeth, and one anterior npproximate lateral tooth in both 

 valves, situate near the primary teeth ; two remote lateral 

 muscular impressions, united by a pallial impression ; ligament 

 external. 



1. Cythebea incrassata. — The Thickened Cytherea, pi. 

 LXXXIV. fig. 4. 



Venus incrassata. Sowerby, II. p. 126, pi. 155, figs. 1, 2. 



Nearly orbicular ; slightly oblique ; sub-compressed ; smooth, 

 with shallow lines of growth ; anterior side a little concave 

 uuder the beaks ; lunette large, and not well defined ; internal 

 margin entire. 



The Upper Marie, Isle of "Wight. 



2. Cytherea parva. — The Small Cytherea, pi. LXXXIV. 

 fig. 20. 



f'cnus parva. Sowerby, VI. p. 32, pi. 518, figs. 4, 5, 6. 



Transversely obovate ; rather convex ; beaks obtuse ; sur- 

 face smooth, with remote shallow lines of growth ; lunette 

 narrow. 



The Gault, Folkstone ; and Ridge, Wiltshire ; and tho 

 Lower Greensand, Parham and Blackdown. 



3. Cytherea lineolata. — The Lineated Cytherea, pi. 

 LXXXIV. fig. 28. 



Fenus lineolata. Sowerby, I. p. 57, pi. 20, upper figure. 



Transversely ovate, subcordate ; rather ventricose ; anterior 

 side smooth ; the other portions covered with zig-zag striae ; 

 beaks prominent; internal margin entire; substance of the 

 shell very thick. 



The Greensand, Blackdown. 



4. Cytherea convexa. — Tho Convex Cytherea, pi. 

 LXXXIV. fig. 19. 



C. convexa. Brongniart, Env. de Paris, pi. 8, fig. 7. 



C. Scutellaria (?) Mantcll, Geo. Suss. p. 263, pi. 25, fig. 2. 



