BIVALVIA. 121 
Spec. Char. Testd transversd, elongato-ovatd, equilaterali, leviter convead, levigata, 
vel tenuissimé striata ; utringue rotundatd, dente cardinali unico, obtuso ; lateralibus nullis, 
foved ligamenti elongata obliqua. 
Shell transverse ovate, equilateral, slightly convex rounded at both extremities, 
smooth, or with very fine lines of growth; hinge with one cardinal tooth, no lateral 
teeth, ligamental area elongated, and oblique. 
Length, #ths. Height, -',ths. of an inch. 
Locality. Coralline Crag, Sutton. 
Red Crag, Walton Naze, and Sutton. 
Mam. Crag, Chillesford. 
This shell is abundant in the Coralline Crag, but the specimens are generally small, 
rarely exceeding half an inch. Fig. 11, 4, is from the Red Crag, and measures at least 
three quarters of an inch. Among alarge number of individuals a considerable varia- 
tion may be observed, but these differences are principally in the proportional dimen- 
sions, although some specimens have occasionally a more triangular form (fig. 11,a). It 
is furnished with one somewhat prominent but obtuse tooth in the right valve, with a 
depression before it, and in the left valve there are two teeth, when perfect, which is 
not often the case, one immediately beneath the umbo, erect and compressed, the other 
decumbent along the margin and atright angles to the other; the ligamental area slopes 
obliquely backwards, forming a thickened ridge, against which it rested. The impressions 
by the adductors are large and rather elongated, while that formed by the edge of the 
mantle is at some distance within the margin of the shell, and is without any inflection, 
and in some thin specimens from the Coralline Crag, fine radiating lines are visible in 
the interior. 
This is the largest species of Kellia that I am acquainted with, and strongly resembles 
in form a shell from the Paris basin, to which it was assigned in my Catalogue; but 
by a comparison with a specimen from the Older Tertiaries of this country, now in the 
cabinet of Mr. John D'Urban, and which probably is identical with the Psammotea dubia, 
Desh, a material difference is exhibited sufficient to prove them specifically distinct, as 
in that shell the hgament is placed on the outside, whereas in ours it is wholly internal. 
A recent species from the Coast of Lower California, described and figured by 
Conrad in the ‘ Journal of the Acad. of Nat. Sci.,’ Philadelphia, 1850, Art. xxii, p- 279, 
pl. 39, fig. 1, under the name of Solecardia eburnea, has a strong generic relationship 
with our Crag fossil, although no doubt specifically distinct. 
4, KELLIA ELLIPTICA, Scacchi. Tab. XII, fig. 13, a—c. 
TELLINA ELLIPTICA, Scacchi. Oss. Zool., ii, p. 14, 1833,) EPs 
Lorires ELLIPTICUS. Scacchi. Ejusd. Cat., i 5, fig. 1, J fide 7 Beeps. 
Luctna optonea. Phil. En. Moll. Sic., vol. i, p. 34, t. 4, fig. 1, 1836. 
Keita FLEXUOSA. S. Wood. Catalogue, 1840. 
— — J. Sowerby. Min. Conch., t. 637, fig. 5, a, 1844. 
Scaccuta evtivvica. Phil. En. Moll. Sic., vol. ii, p- 27, t. 14, fig. 8, 1844. 
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