32 SUPPLEMENT TO GREAT OOLITE MOLLUSCA. 
PecTen inazguicostatus, Phil. Tab. XXXITI, figs. 1, la. 
PrcTEN InZauricostatus, Phil. Geol. York., i, pl. 4, fig. 10. 
— — D’Orb. Prodrome, p. 373. 
— octocostatus, Roemer. Ool., p. 69, pl. 3, fig. 18. 
—  In#quicostatus, Mor. Cat. Brit. Foss., 1854, p. 176. 
— — Oppel. Juraformation, p. 607. 
Testa ovato-acuta, convexa, longitudinaliter, 8 costata, concentrice lineata, costis con- 
vexis latis sulcis conformibus in dorso hinc inde dentatis, duobus mediis latioribus, lineis 
ewilibus confertis sublamellosis auriculis subequalibus longitudinaliter lineatis. (Roemer pro 
valva dextra.) Valva sinistra costis (8) angustis, elevatis rotundis asymmetricis, subnodosis, 
interstiis 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, slightly elevated coste (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 cost, 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. 
Pectren articutatus, Schloth. Tab. XXXIII, fig. 12. 
Precren articuLatus, Schloth. Petref., pp. 227, 228. 
— — Goldf. Petref., p. 47, tab. 90, fig. 10. 
— — Roemer. Verst., p. 68. 
Testa ovato-acuta convexa, costis angustis acutis, subequalibus cingulatis acuminatis, sul- 
cis duplo latioribus concavis subtillissime transversim striatis, auriculis inequalibus lamelloso- 
lineatis costulisque virgatis. (Goldfuss.) 
Shell ovately pointed, convex ; radiating coste elevated, narrow, acute, more or less 
unequal, with acute transverse lamelle; interstitial sulcations wider than the coste, 
concave, with delicate transverse striations ; auricles unequal, with radiating ribs crossed by 
lineal lamella. The more numerous ribs (about twenty-four), their irregularity and in- 
equality, will distinguish it from P. vzmineus, 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. 
