te 
KOCENE MOLLUSCA. 
OsTREA FLABELLULA. J. Sowerby. Min. Conch., t. 253, 1819. 
om — ? Basterot. Coq. Foss. des Env. de Bord., p. 72, 1825. 
— — Deshayes. Coq. Foss. des Env. de Par., p. 366, pl. 63, figs. 5—7, 
1825. 
_— — Goldfuss. Petr. Germ., t. 11, p. 14, No. 33, pl. 76, fig. 6, a—yg. 
= — Galeotti. Mem. de I’ Acad. de Brux., t. xii, pl. iv, fig. 6, a, 6, 1837. 
—= — Nyst. Coq. Foss. Belg., p. 323, pl. 29, fig. 3, a, a’, 4, b', 1843. 
— — Bronn. Leth. Geogn., B. iii, p. 352, t. 39, fig. 15, a—e, 1848. 
— — J. Sowerby, in Dixon’s Geol. of Sussex, p. 95, pl. 4, fig. 5, 1850. 
— — Deshayes. An. sans Vert. du Bassin de Par., p. 120, 1860. 
— DE£FORMIS. Id. Coq. Foss. des Envy. de Par., t. i, p. 346, pl. 55, figs 7, 8. 
—  SUBPLICATA. Id. - - - - p. 345, pl. 48, fig. 3. 
—  BIPRONS. Ti. 2d edit. Lam., t. vii, p. 242, 1836. 
Spec. Char. O. testé cuneatd vel ovato-orbiculari ; valvd inferiore plicatd, plicis 
radiantibus, rugosis, arcuatis, hinc indé furcatis ; valvd superiore pland concentricé striata ; 
intus levi vel obsoleté ad marginem denticulata. 
Shell wedge-shaped or ovately orbicular ; lower valve plicated or ribbed ; ribs rugose, 
radiating, and bifureating in the older shell; upper valve flat, concentrically striated, with 
the inner margin finely or obsoletely denticulated. 
Longest diameter, 13 inch. 
Localities. Barton, Bracklesham, Bramshaw, Clarendon, Southampton, Stubbington, 
Whitecliffe Bay (Hdwards), Bagshot, Clewett’s Green, Headley on the Iiill, Orpington, 
Sundridge, (Prestwich). 
France, Grignon, Parnes, Courtagnon (Des.), Bayonne (D’ Archiac). 
Belg., Le sables d’Uccle, de St. Gilles, de Foret, de Lacken, &c. (Wyst). 
The two specimens from Barton, figured in Brander, Nos. 84 and 85, pl. vii, are 
considered by some authors to belong to two distinct species, viz., O. flabellula and 
O. cymbula. 
In Mr. Edwards’s cabinet is a group of these shells from Barton, adhering to each other, 
one of which possesses the ovate form of cymdula, while another has the cuneate or typical 
form of Ch. plicata, Br., 85; and I cannot imagine that they were otherwise than the 
offspring of the same parent, and I believe that the two shells figured in Brander belong 
to the same species. Groups of these varying forms are not uncommon also at 
Bracklesham. 
The English specimens vary much in outline, some being cuneiform or triangular, while 
others are oval: this difference docs not appear to be the result of impediment to the 
uatural growth, and it is principally by the outward form that the specific distinction has 
been made, the angular one constituting /abellula, and the ovate one cymbula. Sometimes 
this species adheres broadly and firmly to some foreign body, and a large space is left 
upon the shell denoting the place of adherence, while in other specimens there is scarcely the 
