196 MOLLUSCA FROM THE CRAG. 



1. CYPRINA ISLANDICA. Linn. Tab. XVIII, fig. 2 ad. 



PECTUNCULUS MAXIMUS. List. Hist. Conch., fig. 108, 1685. 



_ Dacosta. Brit. Conch., p. 183, t. xiv, fig. 5, 1778. 



VENUS ISLANDICA. Linn. Syst. Nat., ed. 12, p. 1131, No. 124, 1767. 



Will. Zool. Dan., vol. i, p. 29, pi. xxviii, figs. 1 5, 1776. 



ICELANDICA. W. Wood. Ind. Test., pi. vii, fig. 41, 1825. 



MEKCENABIA. Penn. Brit. Zool., ed. iv, vol. iv, p. 94, pi. liii, fig. 47. 



BUCARDIUM. Born. Mus. Caes. Vind., t. iv, fig. 11, 1780. 



EQUALIS. J. Sow. Min. Conch., t. xxi, 1813. 

 CYPBINA ISLANDICA. Ency. Meth., pi. 301, fig. 1 a, b, 1789. 



Phil. En. MoU. Sic., vol. ii, p. 31, 1844. 



Nyst. Conch. Foss. de Belg., p. 146, pi. ix, fig. 1, and pi. ii, fig. 1, 



1844. 



Agass. Icon, des Coq. Tert., p. 49, t. xiii, figs. 6, 7, 1845. 



Defray. Nat. Hist. New York Zool., pi. xxvi, figs. 268-9, 1843. 



Lovtn. Ind. Moll. Scand., p. 38, 1846. 



ISLANDICOIDES. Nyst. Coq. Foss. Prov. d'Anv., p. 9, No. 33, 1835. 



Pusch. Pol. Pal., p. 74, pi. viii, fig. 5 a c, 1837. 



ANGULATA. Nyst. Rech. Coq. Foss. d'Anv., p. 9, No. 34, 1835. 



MAXIMA. S. Wood. Catalogue, 1840. 



VULGARIS. G. B. Sow. Genera of Shells, No. 32, 1824. 



JEQUALIS. Phil. En. Moll. Sic., vol. i, p. 39, t. iv, fig. 4, 1836. 



Gold/. Pet. Germ., p. 236, pi. 148, fig. 5, a, 6. 

 Agass. Icon, des Coq. Tert., p. 52, t. xiii, fig. 5, 1845. 



ARCTICA VULGARIS. Schum. Essai d'un Nouv. Syst. des Habit, des Vers. Test., p. 145, 

 pi. xiii, fig. 3, 1817. 



Spec. Char. Testa magnd, subcordatd, transversd, vel orbiculari, tumidiusculd; striis 

 aut lineis incrementi tenuibus et irregularibus ; umbonibus acutis mx incurvatis ; latere 

 postico subangulato. 



Shell large, of a subcordate form, sometimes elongate or transverse, at others 

 nearly orbicular, somewhat tumid, covered with fine and irregular lines of growth ; 

 beaks sharp, not prominent, scarcely incurved, posterior side slightly angulated. 

 Diameter, 4J inches. 

 Localities. Cor. Crag, Gedgrave, Ramsholt. 



Red Crag, Button, Bawdsey, Alderton, Felixstow. 

 Mam. Crag, Bridlington, Southwold, Chillesford. 

 Uddevalla and Clyde Beds. 



Recent, British, Norwegian, and North American Seas. 



This is one of the most common and abundant shells of the Coralline Crag, and 

 although perfect specimens are somewhat difficult to obtain in the disturbed portion 

 of the Red Crag, fragments or imperfect specimens are there of no uncommon occur- 

 rence, neither is it very rare in the still more recent deposit of the Mammaliferous 

 Crag. It is found living upon our own coasts in various depths of water from five to 

 thirty fathoms, and mostly where the bottom is of sandy mud, but it is considered as 



