168 CRETACEOUS LAMELLIBRANCHIA. 
A specimen from Lewes, figured by Mantell,' may perhaps be an example of 
this species. 
Remarls.—Only three specimens have been seen, all coming from nearly the 
same horizon. The number of ribs on those from Haling and Gravesend is fewer 
than on the specimen from Stratford, but in other characters they agree. 
Types.—In Dr. Blackmore’s collection, and in Mr. G. EH. Dibley’s collection. 
Distribution.—M. cor-anguinum zone of Halng pit, South Croydon, of 
Gravesend, and of Stratford, near Salisbury. 
Proren (Cutamys) Mintent, Sowerby, 1886. Plate XXXI, figs. 3a, b, 4, 5, Ga, b. 
1836. Prcren Minunri, J. de C. Sowerby. Trans. Geol. Soe., ser. 2, vol. iv, pp. 
241, 842, pl. xvii, fig. 19. 
1850. —_ —— A. dOrbigny. Prodr. de Pal., vol. ii, p. 169. 
1854. — Miuzert, J. Morris. Cat. Brit. Foss., ed. 2, p. 176. 
1870. — = F. J. Pictet and G. Campiche. Foss. Terr. Crét. Ste. 
Croix (Matér. Pal. Suisse, ser. 5), p. 214. 
Description.—Shell rather small, ovate, nearly equilateral, the dorsal third 
narrowing rapidly ; height greater than length. Margins well rounded, but the 
antero-dorsal and postero-dorsal more or less concave, and the former longer than 
the latter; inequivalve. Apical angle about 99°. Hars very unequal. 
Right valve shehtly convex, flattened, with numerous slightly elevated, rounded 
radial ribs, which are smooth or slightly scaly, and separated by broader, shallow 
grooves. Anterior ear long, with a well-marked sinus; posterior ear much smaller, 
triangular, with outer angle obtuse. 
Left valve much more convex than the right, especially in the median line 
towards the umbo; ornamented with numerous (usually 45 to 54) radial ribs, 
which are slightly elevated, flattened or rounded, and smooth (except a few of the 
posterior ribs); on the dorsal part the furrows are narrower than the ribs, and 
pitted, but ventrally they may be broader, and are always shallow. A secondary rib 
may appear in the furrows towards the ventral border. Anterior ear considerably 
larger than the posterior, with seven or eight radial ribs and a few growth-lines ; 
its outer angle almost rectangular. Posterior ear smaller, with obtuse outer angle. 
Measurements : 
(1) (2) (3) (4) (5) (6) 
Length . 28 . 26 > 2 2 207594159. 12) 5 anme 
Height . 32 . 295 . 24 Wp 5 ley gE) gg 
(1—6) All from Blackdown. 
' «Foss. S. Downs’ (1822), p. 203, pl. xxv, fig. 6. 
