190 MOLLUSCA FROM THE CRAG. 
It appears quite distinct from the preceding, in being flatter or more compressed, 
and the line of hinge much narrower ; it is also athinner shell. The exterior markings 
are much alike in both species, having somewhat flat ridges with narrow spaces between 
them ; they pass obliquely over the shell from the posterior to the anterior side, some 
of which run out at the ventral margin, and cut the lines of growth at an acute angle ; 
the hinge is composed of one large triangularly formed tooth in the right valve, with 
one anterior lateral tooth at the extremity of the lunule; in the left valve are two 
diverging cardinal teeth, with the triangular space between them, and the more distinct 
lateral tooth, or that which has on the outside of it a depression for the elevated edge 
of the opposite valve, is on the posterior side. This has also the small auxiliary 
muscular impression on the anterior side, and the mantle mark is without the least 
indentation. In the adult shell the margin is crenulated, while the younger specimens 
have it quite smooth. The two valves are occasionally found united in the less 
unmixed portion of the Red Crag Deposit at Walton-on-the-Naze. 
. 
18. AsTARTE DigiTaRIA, Linneus. Tab. XVII, fig. 8 a—d. 
TELLINA DiaiTaRta. Linn. Syst. Nat., edit. 12, p. 1120, No. 71, 1767. 
—_ — Chemn. Conch. Cab. vi, p. 126, t. xii, fig. 121, 1782. 
Luctna pieiranis. Lam. Ann. sans Vert., t. v, p. 544, 1818. 
— — ? Bast. Bord. Foss., p. 87, 1825. 
— — Phil. En. Moll. Sic., vol. i, p. 33, t. ili, fig. 19, 1836. 
— — Td. 3 vol. ii, p. 25, 1844. 
— _ Desh. 2d edit. Lam., t. vi, p. 231, 1835. 
— — Reeve. Conch. Icon., pl. ii, fig. 65. 
— opieirarta. S. Wood. Catalogue, 1840. 
— -curviraDIATA. Myst. Rech. Coq. Foss. d’Anv., p. 6, pl. i, fig. 20, 1835. 
— — Id. Coq. Foss. de Belg., p. 137, pl. 6, fig. 12, 1844. 
Ency. Method., pl. 292, fig. 5. 
Spec. Char. Testé minutd; orbiculato-ovatdé subequilaterali, compressiusculd; striis 
obliquis incurvis, umbonibus depressis; dentibus lateralibus distincti$; margine integer- 
Timo. 
Shell small, roundedly ovate, nearly equilateral, somewhat compressed, covered 
with elegantly curved, oblique, impressed striae; umbones depressed ; lateral teeth 
distinct ; margin smooth. 
Diameter, 2ths of an inch 
Localities. Cor. Crag, Sutton. 
Red Crag, Sutton, Walton-on-the-Naze. 
Recent, Mediterranean. 
Abundant in the Coralline Crag at Sutton, and by no means rare in the more 
genuine portion of the Red Crag at Walton-on-the-Naze, where I have found the two 
valves united. The only trifling difference I can detect between the British fossil and 
