BIVALVIA. 215 
1. ARTEMIS LENTIFORMIS, J. Sowerby. Tab. XX, fig. 7 a—e. 
Venus Exoneta. Parkinson. Org. Rem., vol. iii, p. 189, 1811. 
— pntirormis. J. Sow. Min. Conch., t. 203, 1818. 
Anremis ExoLETA. Nyst. Coq. Foss. Belg., p. 184, pl. xiv, fig. 1, 1844. 
— .entrrormis. S. Wood. Catalogue, 1840. 
— — Potiez et Mich. Catal. des Moll. de Douai, tom. xi, p. 227, No. 13, 
1844. 
Spec. Char. Testa orbiculari, lentiformi, compressiusculd inequilaterali, crassa ; strits 
concentricis, magnis, confertis ; lunuld cordatd, impressd; margine dorsali convexiusculo 
postice subangulato. 
Shell orbicular, lentiform, somewhat compressed, slightly inequilateral, thick ; 
covered with numerous large, close set, concentric striz ; a deeply-seated heartshaped 
lunule; dorsal margin slightly convex; posterior side subangulated. 
Diameter, 2 inches. 
Localities. Cor. Crag? Gedgrave. 
Red Crag, Sutton, Walton-on-the-Naze. 
In the Coralline Crag it is very rare; indeed I have obtained only one specimen, 
which is represented at fig. 7 c, and this is partly imbedded in the matrix with its best 
characters obscured; but in the Red Crag it is one of the most abundant shells at 
Walton-on-the-Naze. 
In the ‘Mineral Concology’ the Crag shell was considered to differ from /eaus 
exoleta (with which it had been placed by Parkinson) sufficiently to justify a specific 
distinction, and as this is a genus in which the species do not appear to possess a great 
range in variation, I have retained for it Mr. Sowerby’s name, although these dif- 
ferences are probably the effect of locality, or the result of external conditions. | 
Our shell is certainly flatter than /. exoleta, but not thinner ; the strize or ridges are 
as large and broad as those which ornament the recent species; there is a slight 
angularity in the outline on the posterior side, a little beyond the termination of the 
large ligament, anda slight slope upon the dorsal edge, differing therein from V. ezoleta ; 
this slope is not naked, but covered with numerous striz or fine lmes of growth. The 
sinus in the mantlemark is large, deep, and linguiform in a direction across the shell ; 
[have never seen a specimen with this sinus so vertical as it is represented in ‘ Min. 
Conch.’ above referred to. 
2. ArTemis tincta, Pulteney. Tab. XX, fig. 6 a—d. 
Venus trncta. Pulé. Hutchins, Dorset, p. 34, fide Forb. and Hanl. 
— xxotera. Penn. Brit. Zool., vol. iv, p. 94, pl. lvi, fig. 49. 
—_ -— var. 8. Mat. and Rack. Linn. Trans., vol. viii, p. 87, pl. ili, fig. 2, 1807. 
— sinvata. Turt. Ed. Linn., vol. iv, p. 233, 1806. 
— wupra. Poli. Test. Sicil., t. xxi, fig. 8. 
— sactea. Mont. Test. Brit. Sup., p. 46, 1808. 
