32 SUPPLEMENT TO GREAT OOLITE MOLLUSCA. 



Pecten iNiEQUicosTATUs, Fliil. Tab, XXXIII, figs. \,\ a. 



Pecten iNiEauicosTATUs, FMl. Geol. York., i, pi. 4, fig. 10. 



— — TfOrh. Prodrome, p. 3/3. 



— OCTOCOSTATUS, Roemer. Ool., p. 69, pi. 3, fig. 18. 



— iN^QUicosTATUS, Mor. Cat. Brit. Foss., 1854, p. 176. 



— — Oppel. Juraformation, p. 607. 



Testa ovato-acufa, convexa, longitudinaliter , 8 costata, concentrice lineata, cosHs con 

 vexis latis sulcis conformibus in dorso Jdnc inde dentatis, duohus mediis latioribus, lineis 

 exilibus confertis sublamellosis auriculis subaqualibus longitudinaliter lineatis. {Roemer pro 

 valva dewtra.) Valva sinistra costis (8) angustis, elevatis rotundis asymmetricis, subnodosis, 

 intersfiis latis irregulariter concentrice striatis. 



A convex, subsequivalve, acute-pointed Pecten, with large, nearly equal auricles ; the 

 surfaces of both the valves having irregular, concentric striations and several large folds of 

 growth. The right valve has broad, shghtly elevated costse (8), which are unequal and 

 slightly defined towards the posterior side, separated by narrow and but little depressed 

 sulcations, which are distinct upon the inner surface of the valve ; the left valve has eight 

 narrow, elevated, but rounded costae, of which those upon the sides are small and 

 unsymmetrical ; the intervening spaces are broad upon the middle of the valve, and very 

 narrow laterally ; the auricles are obliquely lineated. 



Geological Positions and Localities. Rarely in the Cornbrash and Kelloway Rock of 

 Scarborough, more commonly in the Coralline Oolite of Malton, but it is seldom well 

 preserved at either of these geological positions ; Roemer makes a similar statement 

 respecting its occurrence at Lindner Berges. 



Pecten articulatus, ScJdoth. Tab. XXXIII, fig. 12. 



Pecten articulatus, Schloth. Petref., pp. 227, 228. 



— — Goldf. Petref., p. 47, tab. 90, fig. 10. 



— • — Roemer. Verst., p. 68. 



Testa ovato-acuta convexa, costis angustis acidis, subcequalibus cingulatis acuminatis, sul- 

 cis duplo latioribus concavis subtillissime transvershn striatis, auriculis incequalibus lamelloso- 

 lineatis costulisque virgatis. (Goldfuss.) 



Shell ovately pointed, convex ; radiating costas elevated, narrow, acute, more or less 

 unequal, with acute transverse lamellae ; interstitial sulcations wider than the costa?, 

 concave, with delicate transverse striations ; auricles unequal, with radiating ribs crossed by 

 lineal lamellae. The more numerous ribs (about twenty-four), their irregularity and in- 

 equality, will distinguish it from P. vimineus, Sowerby, a species which abounds in the 

 Inferior Oolite. 



Geological Positions and Localities. Pecten articulatus occurs in the Cornbrash of 

 the Yorkshire coast, and more frequently in the Calcareous Grit and Coralline Oolite of the 

 same county. 



