History of British animals - University of Guam Marine Laboratory

446 MOLLUSCA. VENERIDiE. Cvtherea.519- C. orbiculata.— Orbicular, compressed and cancellated;beaks small, with a minute cordiform impression in front.Venus orb. Mont. Test. Brit. Sup. 42. t. xxix. f. 7— Cyprina orbiculata,Turt. Biv. Brit. 138— Dunbar, Mr Laskey.Diameter fths of an inch ; white; margin plain ; two approximating teeth,and one transverse, and rather remote where the margin is angular.EXTINCT SPECIES.1. C. lentiformis Orbicular, depressed, with concentric, reflected, minute,imbricated ridges ; posterior slope depressed, terminated by an angle at themargin Venus exoleta, Park. Org. Rem. iii. 189. V. lent. Sower. Min.Conch, t. cciii— Crag.2. C. Scutellaria Manl. Geol. 263. t. xxv. f. 2—Plastic Clay.G£N. CXXVIII. VENUS.—Shell suborbicular, inequilateral; hinge with three diverging teeth in each valve, the middleone in the left valve strong and bifid.* Marginwithin crenulated.— 520. V. verrucosa. — Shell tumid, heart-shaped,with numerousconcentric ridges, broken into tubercles by longitudinalgroovesat both extremities.Pectunculus omnium, crassissimus, List. Conch, t. cclxxxiv—Concha—cinerea, Borl. Corn. 275. t. xxvii. f. 32. V. ver. Linn, Syst.i. 1 130.—V. ervcina, Perm. Brit. Zool. iv. 94. t. liv. f. 48— V. ver. Don. Brit.Shells, t. xliv. Mont. Test. Brit. 112. Turt. Biv. Brit. 140 Englishand Irish shores.Length two inches and a quarter, breadth a little more ; rufous ; strong ;depression before the beaks heart-shaped, the posterior, or cartilage depression,distinctly displayed only on the left valve ; the ridges are sharp, reflectedand striated, and, towards the beaks the furrows are striated longitudinally; the margin crenulated within.521. V. cassina.— Shell slightly compressed and heart-shaped,with numerous concentric entire ridges.Linn. Syst.i. 1130 V. erycina worn, Penn. Brit. Zool. iv. t. liv. f. 48.A V. lactea, Don. Brit. Shells, t. cxlix V. cass- Maton and Ruekett, Lin. Trans, viii. 79. t. ii- f. 1. Turt. Biv- Brit. 141. t. ix. f. 1—Various parts of coast.tjjeDiameter about two inches ; whitish ; ridges irregular in size, curving towardsthe hinge;left valve at the ligament depressed and striate ;marginsometimes very obtuse—This species is distinguished from the preceding bybeing less tumid, and by the ridges being entire.522. V. reJJexa.— Shell compressed, dorsal margin behind thebeaks nearly straight; concentric ridges risinginto thin platesxctrally, where they are waved and deflected.Laskey, Wern. Mem. i. 384. t. viii. f. 1. Mont. Test. Brit. Sup. 40.Flem. Encyc. Edin. vii. 95. t. ccvi. £ 1. Turt. Biv. Brit. 142. t.x. f. 1,2 Various parts of the coast from Devon to Zetland.3