192 CRETACEOUS LAMELLIBRANCHIA. 
PEcTEN (AVQUIPECTEN) SARUMENSIS, sp. nov. Plate XXXVII, figs. 1, 24,0, 3. 
Deseription—Shell small, shehtly inequilateral, height and length nearly equal, 
outline rounded, convexity small. Apical angle 107° to 111°. Ears rather large. 
Right valve ornamented with very numerous (fifty to sixty) narrow, well- 
marked, radial ribs, which are separated by deep, narrow grooves. The ribs are 
often slightly unequal, sometimes alternately, the smaller ribs beimg imtroduced 
later than the larger. The ribs bear numerous small, similar, spiny scales, placed 
either vertically or sloping, and sometimes having a roughly concentric arrangement ; 
near the umbo concentric lamelle occur. Postero-dorsal margin with fine oblique 
strie. Anterior ear long, with a deep sinus and four radial ribs with spines. 
Posterior ear much shorter, with three or four radial, spiny ribs. 
Left valve not seen. 
Measurements : 
(1) (2) (3) (4) 
Leneth ; 8°5 : 70 . 6 d 5°25 mm. 
Height : 8:0 ; 6275 ’ 6 y 5:0 e 
(1—4) A. quadratus zone, East Harnham, Salisbury. 
Affinities —In form this species resembles P. campaniensis, but is easily 
distinguished by the much larger number of ribs. The ornamentation resembles 
that of P. pewatus, but the shell is without radial folds, the ribs are fewer, and the 
apical angle larger. Radial folds occur on even the smallest specimens of 
P. pexatus. 
Types.—In Dr. Blackmore’s collection. 
Distribution.—A. quadratus zone of East Harnham (Salisbury). B. mucronata 
zone of Clarendon (Salisbury). 
PEcTEN (AEQUIPECTEN) CAMPANIENSIS, @’ Orbigny, 1847. Plate XX XVII, figs. 4—8. 
1847. Proren cAmpantrensis, A. d’Orbigny. Pal. Franc. Terr. Crét., vol. i, p. 
620, pl. ccecexl, figs. 12—16. 
1850. — = — Prodr. de Pal., vol. ii, p. 251. 
1870. — — F. J. Pictet and G. Campiche. Foss. Terr. Crét. Ste. 
Croix (Matér. Pal. Suisse, ser. 5), p. 215. 
1887. oo _- A. Peron. Hist. Terr. Craie 8.E. du Bassin Anglo- 
Parisien (Bull. Soe. Sci. hist. et nat. 
de l’Yonne, ser. 3, vol. xii), p. 163. 
1889, — -= O. Griepenkerl. Senon von Kénigslutter (Palaeont. 
Abhandl., vol. iv), p. 44. 
