BIVALVIA. 231 
Locality. Red Crag, Sutton, Walton Naze. 
Mam. Crag, Bramerton, Postwick, and Chillesford. 
This shell in some parts of the Red Crag is exceedingly abundant, though rare at 
Walton on the Naze. At Sutton I have frequently found specimens with the valves 
united and the ligament preserved, strong presumptive evidence of their having lived 
and died in the locality wherein they were found. 
This species was named by the late Rev. G. R. Leathes, in consequence of its con- 
nexion or resemblance to 7! fenuis, perhaps its nearest relative. It is somewhat in form 
like 7. Balthica, but is not so tumid or thick: it differs from 7 ¢enwis in having more 
height, with a greater convexity in the ventral margin; the two teeth in each valve are 
alternately simple and bifid, the bifid one is anterior in the left valve, and vice versa ; 
and there are no lateral teeth, but there is a very distinct one on the anterior side in 
T. tenuis, and in that species the mantle mark is comparatively larger. 
In well-preserved specimens, the surface is covered with fine concentric striz, or 
lines of growth, more especially upon the posterior slope, and the right valve is the 
more tumid of the two; there is also a slight difference in the magnitude of the 
palleal sinus in the opposite valves. 
The shell which really makes the nearest approach to this species is one that was 
brought from the 8. E. Coast of Australia. 
7. TeLutiIna Bartuica, Linneus. Tab. XXII, fig. 1, a—e. 
Trttina Baurutca. Linn. Syst. Nat., ed. 12, p. 1120, No. 68. 
_ — Born. Test. Mus. Cees. Vind., p. 38, t. 11, fig. 14, 1780. 
a _ Phil. En. Moll. Sic., vol. i, p. 28; and vol. 2, p. 22. 
= Battica. Lyell. Phil. Trans., 1835, p. 34, var. a, pl. 11, figs. 1,2; var. b, 
figs. 3, 4. : 
—  sonipuLa. Pulteney. In Hutchin’s Hist. Dorset, p. 29. 
— — Woodw. Geol. of Norf., pl. 2, fig. 13, 1832. 
— — Lovén. Ind. Moll. Scand., p. 41, 1846. 
— — Middend. Mal. Ross., loc. cit., p. 577, 1849. 
— ruBRA. Da Costa. Brit. Conch., p. 211, t. 12, figs. 4, 4, 4. 
— CARNARIA. Penn. Brit. Zool., vol. iv, p. 88, pl. 49, fig. 32. 
— _ J. £. Gray. List of Brit. Moll., p. 41, 1851. 
—  zoNnaTa. Gmel. Syst. Nat., p. 3238, No. 52. 
— INconspicua. ? Brod. and Sow. Zool. Journ., vol. iv, p. 363, 1829. 
— — 2 Gray. Zool. Beechey’s Voy., p. 153, t. 41, fig. 6, 1839. 
—  Grornnanpica. (Beck.) Lyell. Trans. Geol. Soc., vol. vi, 2d series, pl. 16, fig. 8, 
1859. 
PsamMMosBia FuscA. Say. Journ. Acad. Nat. Sc., v, p. 220. 
— SOLIDULA. Turt. Brit. Biv., p. 95, t. 8, fig. 2, 1822. 
SANGUINOLARIA FUSCA. Conrad. Am. Mar. Conch., 34, pl. 7, fig. 1. 
— -- Dekay. Nat. Hist. New York (Zoology), pl. 32, fig. 304. 
LIMICOLA CaRNARIA. “Leach.” Sec. Gray. 
