PECTEN. 185 



Leymerie {noii Minister) ; but Rohiitahlinvs, which is one of the forms of this species 

 witli fewer and coarser ribs, has the priority. P. aptirusis is phiced l)y I*ictet niid 

 Campiche as a synonym of both P. BohinalJinus and P. Dutemjjlei. 



Morris regarded P. Dutem,plei and P. GaUiennei as synonyms of intei-dnafiis, 

 Leymerie, and included in it both Upper and Lower Grreensand forms. 



P. Bnrretti, Seeley, from tlie Cambridge Grreensand, is founded on a worn 

 specimen, but is probably identical Avith P. Uohiwihlinm, unless the numerous riljs 

 on the anterior left ear be regarded as a distinguishing character. 



Types. — The type of P. inter striatus, Leymerie, came from Les Croutes, Aube. 

 D'Orbigny's specimens of P. Bohinaldinns were obtained from the Neocomian of 

 St. Sauveur, etc. 



Distribution. — Perna-hed of Atherfield and East 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. Eye Hill 

 Sand of Warminster. Chalk Marl, zone of A. Mantelli (Meyer's Beds 11 and 12) 

 of Dunscorabe, and Bed 11 of Beer Head. 



Pecten (Chlamys) Stutciiburianus, Sowerhy, 18:36. Plate XXXV, fig. 11. 



1836. Pecten Stutchburiensis, J. de C. Sowerhy. Trans. Geol. Soc, ser. 2, vol. 



iv, p. 342, pi. xviii, fig. 1. 

 — — Stutchburianus, Soiverby. Ibid., 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 i-ibs, 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 striae : 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) 



Length . 90 . 79 . 50 . 58 mm. 

 Height . 112 . 90 . 67 . 68 „ 



(1—3) Haldou, (4) Blackdowu. 



Affinities. — No definite opinion can be given as to the afiinities of this form, 



24 



