PECTEN. 185 
Leymerie (non Minster); but Robinaldinus, which is one of the forms of this species 
with fewer and coarser ribs, has the priority. P. aptiensis is placed by Pictet and 
Campiche as a synonym of both P. Robinaldinus and P. Dutemplei. 
Morris regarded P. Dutemplei and P. Galliennei as synonyms of interstriatus, 
Leymerie, and included in it both Upper and Lower Greensand forms. 
P. Barretti, Seeley, from the Cambridge Greensand, is founded on a worn 
specimen, but is probably identical with P. Robinaldinus, unless the numerous ribs 
on the anterior left ear be regarded as a distinguishing character. 
Types.—The type of P. interstriatus, Leymerie, came from Les Crotites, Aube. 
D’Orbigny’s specimens of P. Robinaldinus were obtained from the Neocomian of 
St. Sauveur, ete. 
Distribution.—Perna-bed of Atherfield and Kast Shalford. Atherfield Beds of 
Sevenoaks. Hythe Beds of Hythe and Lympne. Lower Greensand of Faringdon, 
and perhaps Upware.  Ferruginous Sands of Shanklin. 
Chloritic Marl of Maiden Bradley. Upper Greensand of Ventnor. Rye Hill 
Sand of Warminster. Chalk Marl, zone of A. Mantelli (Me¥er’s Beds 11 and 12) 
of Dunscombe, and Bed 11 of Beer Head. 
Prcren (Cunamys) Sturcupurianus, Sowerby, 1856. Plate XXXV, fig. 11. 
1836. Prcren Strurcupuriensis, J.de C. Sowerby. Trans. Geol. Soc., ser. 2, vol. 
iv, p. 342, pl. xviii, fig. 1. 
— ~ Srurcupurianus, Sowerby. Tbid., p. 360. 
1854. -_ — J. Morris. Cat. Brit. Foss., ed. 2, p. 177. 
Description —Shell large, ovate, higher than long, flattened, convexity small. 
Ornamented with numerous slightly-raised ribs, which on the greater part of the 
valve are alternately broad and very narrow, and are separated by narrow grooves ; 
but towards the margin the alternation of ribs may be less distinctly marked, and 
the interspaces broader with indications of oblique striz: the larger ribs have 
flattened or rounded summits, and are ornamented with transversely-placed scales. 
Umbones pointed ; apical angle rather small (about 85°); ears high, not very dis- 
tinctly separated from the rest of the valve. 
Measurements (approximate) : 
(1) (2) (3) (4) 
Leneth ; 90°57, = 0 58 mm: 
Height GS ee 0) GZ or 6843 
(1—3) Haldon, (4) Blackdown. 
Affinities —No definite opinion can be given as to the affinities of this form, 
DA 
