Page:Quarterly Journal of the Geological Society of London, vol. 26.djvu/573

 pressed ; anterior side rounded, posterior but little attenuated ; ornamented by concentric acute folds and striae.

Dimensions. Length 0-4 inch; height 0.12 inch; diameter 0.1 inch ; length of anterior side 0.22 inch.

This species belongs to the group Cercomya, Agassiz, but differs from the two other Liassic species (A. precursor, Quenstedt, and A. Delia, D'Orb, or A, sinemuriensis, Martin) by its form and plications.

Locality. Ammonites-Jamesoni zone, Aston Magna (Slatter).

Inoceramus incurvatus, nov. sp. (Pl. XXVI. figs. 2 & 2 a.)

Shell subrhomboidal ; hinge-line nearly straight ; umbones sub- marginal, inflated and incurved ; outer surface marked with concentric folds.

The figure of the fossil is not perfect, but the distinctive characters are the gibbosity of the umbonal region and the strongly incurved beaks.

Length of longitudinal axis 2-3/4 inches.

Locality. Zone of Ammonites capricornus, Cheltenham (R. T.).

Arca Stricklandi, Tate.

Arca truncata, Buckman, Geol. Cheltenham, t. 5. f. 6, p. 26 (1845), non Arca truncata, G. B. Sowerby (1833), non Arca truncata, Reuss (1843).

Specific name to commemorate the palaeontological labours of Mr. Hugh Strickland in the Lias of Gloucestershire.

Distribution. Zone of Ammonites Jamesoni, Cheltenham ! Aston Magna (Slatter). Yellow Lias, Cheltenham (Buckman).

Leda graphica, nov. sp. (Pl. XXVI. fig. 12.)

Shell elliptical, rounded and inflated in front, posteriorly rostrated, ornamented with fine and closely set concentric striae, which form chevrons on the postmedial line.

Dimensions. Breadth 1 inch ; length of anterior side 0.35 inch : height 0.35 inch ; diameter 0.3 inch.

This species has the general form of L. rostralis, Lamk., and a few other Liassic species, but is distinguished from all, especially by its chevron-like ornamentation.

Locality. Zone of Ammonites capricornus, Mickleton Tunnel (Gavey). (Coll. Geol. Soc. and Geol. Surv. Mus.)

NUCULA UNGULELLA, NOV. Sp. (P1. XXVI. fig. 11.)

Nucula variabilis, Quenstedt, Der Jura, t. xxiii. f. 28, p. 188 (1858), non Sow.; id. Dumortier, Depots Jurassiques, iii. p. 121, 1869.

Shell ovate, subtrigonal.; umbones inflated, depressed, recurved, submarginal ; a keel proceeds from the umbo to the antero-ventral margin, enclosing a subconcave area; anterior margin truncated, posterior elongated and slightly compressed ; ventral margin curved; lunule deeply impressed ; surface covered by distant strong lines of growth ; hinge-line with ten serial anterior teeth and fifteen posterior.