70 MOLLUSCA FROM THE CRAG. 
1. Limopsis aurita, Brocchi, Tab. IX, fig. 2. 
Arca aurita. Broc. Conch. Foss. Subap., p. 485, t. xi, fig. 9, a—é, 1814. 
Protuncunus auritus. Defr. Dict. Scien., t. xxxix, p. 224. 
_— _ Goldf. Pet. Germ., v. ii, p. 163, t. 126, fig. 14, a—d. 
— _ Phil. En. Moll. Sic., vol. i, p. 63; vol. ii. p. 45. 
a — Risso. Hist. Nat. des Princip. Prod. del’ Europ., t. iv, p. 318, 1826, 
i suBLMHvIcaTus. S. Wood. Catalogue, 1840. 
—. — Morris. Cat. Brit. Foss., p. 97, 1843. 
Limopsis auriTa. Sassi. Giorn. Ligust. (ex. Bronn), 1827. 
— — Bronn. Leth. Geo., vol. ii, p. 935, t. 39, fig. 7, a—b, 1838. 
— — Sismonda. Syn. Meth. Ped. Foss., p. 15, 1847. 
TRIGONOCELIA SUBLHVIGATA. Myst. et West. Nouv. Rech. Coq. Foss. d’Anv., p. 12, pl. 2, 
fig. 15, 1839. 
= — Nyst. Coq. Foss. de Belg., p. 244, pl. 26, fig. 2, a—d, 1844. 
Spec. Char. Testd obliqua, rotundato-ovatd, inequilaterd, sublevigatd, auriculata ; 
ewilissime striatd, et tenuissime decussatd ; cardine arcuata, dentibus 10—18 ; margine 
integerrimo, acuto. 
Shell oblique, rounded ovate, inequilateral, nearly smooth, and glossy, with small 
auricles; externally ornamented with very fine striz, crossed by distinct lines of 
growth; hinge line curved, with about 10 to 18 teeth; margin sharp and smooth. 
Longest diameter, % an inch. 
Locality, Cor. Crag, Gedgrave. 
This species has recently been found in abundance in one locality of the Coralline 
Crag, but it appears restricted to that spot, it may possibly have lived on into the Red 
Crag period, as my cabinet contains one specimen from that Formation, which however 
is much waterworn. 
It is subject to a good deal of variation in its outward form, but is always 
more or less obliquely oval, generally becoming especially so in the older speci- 
mens, while in some young shells the valves are nearly equilateral. The hinge is 
composed of a row of denticles, varying from ten to sixteen, those on the shorter or 
rounded side being the greater number, amounting to about nine, the outermost are 
angular and somewhat distant, while the inner ones are close set and vertical; on the 
other side they are fewer, not exceeding seven, sometimes not more than four, these 
are distant, much inclined, and nearly parallel to the hinge line, furthermore they are 
often rough and crenulated upon their edges. The exterior of the shell is smooth and 
even glossy when perfect, with faint but distinct radiating striz and visible lines of 
growth, and the hinge line projects a little beyond the otherwise oval contour of the 
shell, giving it the appearance of auricles, hence its name; the inner margin is 
flattened, smooth, and perfectly free from crenulations, and the impressions by the 
adductors deeply seated; that on the shorter side small and ovate placed near the 
hinge, the other is larger and more distant; the fossette for the cartilage diverges from 
the umbo at an angle of about 90°. 
re es 
