10 MOLLUSCA FROM THE CRAG. 
of its characters, but may be distinguished, if not specifically, certainly as a variety, 
by its sculpture, which is in the form of spinous or squamose radiations. In the 
recent state, the lower or perforated valve, is said to be generally thin and fragile, and 
destitute of the aculeated strie. As the shells found in the Crag are separated or 
detached, they would not be recognised, if this were always the case ; but many of the 
lower valves are alike ornamented with these markings, though they are less con- 
spicuously so than upon the upper ones. The umbo of this is placed very near the 
margin, and is generally slightly recurved; the strie are numerous, although in 
some specimens they are more distant; but in all they have more or less, the 
vaulted or raised, and slightly reflected edges, which as it grows produce the 
series of aculeated or fimbriated striz upon the exterior, though very faintly 
exhibited in the variety called s¢rio/ata. In the very young of some of my speci- 
mens, the shell appears to be free from sculpture of any kind, and this may favour the 
opinion of Mr. Clark. 
3. ANOMIA PATELLIFORMIS, Linneus. Tab. I, fig. 4, a—d. 
ANOMIA PATELLIFORMIS. Linn. Noy. Act. Upsal., vol. i, p. 42, pl. 5, figs. 6, 7, 1773. 
— — Loven. Ind. Moll. Scandin., p. 30, 1846. 
— — Alder, Cat. Moll. North. and Durh., p. 75, 1848. 
— — Forb. and Hanl. Hist. of Brit. Moll., vol. ii, p. 334, pl. 56, 
figs. 5, 6, 1849. 
— — Middendorff. Malac. Ross. (Mem. de I’Acad. des Sc. St. Petersb.), 
p- 521, 1849. 
—  UNDULATIM sTRIATA. Chem. Conch. Cab., t. viii, p. 88, tab. 77, fig. 699. 
— uNpDuULATA. Gmel. Syst. Nat., p. 33, 46. 
— — - Mont. Test. Brit., p. 157, pl. 4, fig. 6, 1803. 
= — Turt. Brit. Biv., p. 230, pl. 18, figs. 8, 9, 10, 1822. 
— _— Brown. Ulust. Conch. Gr. Brit., pl. 34, figs. 2, 3, 1827. 
—_ — Flem. Brit. An., p. 395, 1828. 
— — S. Wood. Catalogue, 1840. 
OsrrEumM striatuM. Dacosta. Brit. Conch., p. 162, pl. 11, fig. 4. 
Osrrea striata. Donov. Brit. Shells, vol. 1, tab. 45, 1801. 
= — Mont. Test. Brit., pp. 153, 580, 1803. 
— — List. Hist. Conch., fig. 36. 
Ency. Meth., pl. 171, fig. 16, and pl. 184, figs. 5, 6. 
Spec. Char. Testd suborbiculari, plicis 20—30 convewxis, undulati-radiatis ; stris 
concentricis crebris, sublaminaceis ; umbone subprominulo a margine remotiusculo. 
Shell suborbicular, ornamented with 20—30 radiating and undulating ribs; con- 
centric striz or lines of growth thick and sublaminated; umbo slightly prominent, 
a little distant from the margin. 
Diameter, 1% inch. 
Locality. Cor. Crag, Sudbourn and Sutton. 
Red Crag, Sutton, Bawdsey, Walton Naze. 
Recent, Britain and Scandinavia. 
