BIVALVIA. 229 
TELLINA ovATA. J. Sow. Min. Conch., t. 161, fig. 2, 1817. 
— — Phil. En. Moll. Sic., vol. i, p. 30 ; vol. ii, p. 23. 
— as Nyst. Coq. Foss. de Belg., p. 108, pl. 5, fig. 3, a, 6, 1844. 
— ovalts. Woodw. Geol. of Norf., p. 43, pl. 2, fig. 11, 1832. 
— saBuLosa. Spengler. Sec. Lovén. 
_ CALCAREA. Wahlenb. Sec. Lyell. Geol. Trans., vol. vi, 2d series, p. 137, pl. 16, 
figs. 9—11, 1839. 
— oo Miller. Ind. Moll. Groenl., p. 20, 1842. 
—_ PROXIMA. Smith. Mem. Wern. Soc., vol. viii, p. 105, pl. 1, fig. 21, 1838. 
— — Sow. Append. Beechey’s Voy., p. 154, t. 44, fig. 4, 1839. 
= — Forb. and Hanl. Hist. Brit. Moll., vol. i, p. 307, pl. 21, fig. 1, 1848. 
_ EDENTULA. ? Brod. and Sow. Zool. Journ., vol. iv, p. 363, 1829. 
— — ? Gray. App. Beech. Voy. Zool., p. 154, t. 41, fig. 5; and t. 44, fig. 7, 
1839. 
—  sorpiIpa. Couthony. Bost. Journ. Nat. Hist., vol. ii, p. 59, pl. iii, fig. 11, 1839. 
—  riancuLarts. Lyell. Phil. Trans., 1835, p. 36, fide Lovén. 
— TENERA. Gray. List Brit. Moll., p. 42, 1851. 
SANGUINOLABIA SORDIDA. Gould. Invert. Massach., p. 67, 1841. 
MacoMa TENERA. Leach. Ann, of Phil., vol. xiv, p. 204, 1819. 
Spec. Char. Testé ovatd, transversd, inequilaterali ; anticé longiore rotundata ; postice 
sub-angulatd ; dentibus utringne binis, lateralibus nullis. 
Shell ovate, transverse, inequilateral; anterior side the longer and rounded: 
posterior obtusely angulate, with two teeth in each valve; lateral teeth none. 
Length, \% inch. Height, 14 inch. 
Locality. Red Crag, Sutton. 
Mam. Crag, Bramerton, Chillesford. 
Clyde Beds, Uddevalla, Russia, Canada. 
Recent, Finmark, N. E. Coast of America, Britain, 
Behring’s Straits (@. B. Sowerby). 
I have never seen the present species from the Older or Coralline, and only rarely 
from the Red Crag, and never at Walton-on-the-Naze. In the Mammaliferous Crag 
Period the two species appear to be more equally distributed, although the oblique 
form is there giving way to its more transverse successor, while this latter species 
only, remains at the present day, and seems to be restricted to the colder regions of 
the Northern Hemisphere. In this, as in the preceding species, there is a considerable 
difference in the form and depth of the siphonal scar in the two valves, and the 
posterior side of this one is much more pointed than that of obliqua, and the line of the 
ventral margin is not only less curved but is somewhat constricted on the posterior 
side. 7. /ata, Middendorff,‘Malac. Ross.,’ found in the Arctic Seas and Behring’s Straits, 
may probably be a dwarf variety of our shell, connecting it with 7. Balthica, which it 
resembles in many of its characters. 
