BIVALVIA. 11 



Pecten personatus, Goldf.'^ Tab. I, fig. 17. 



? Pecten personatus, Goldfuss. Petref., p. 75, t. 99, fig. 5. 



Testa incequivalvi, cequilaterali, sub-orbiculari, convexo-pland, pellucidd, interne 

 (12 — 14) costatd ; valvd sinistrd costis externis minutis crebris lineis concentricis 

 decussatis ; dextrd Icevi, auriculis inaqualibus obtusangidis costatis. (Goldfuss.) 



Shell inequivalve, equilateral, sub-orbicular, slightly convex, pellucid, its inner surface 

 having costae (12 — 14), left valve with very numerous external irregular radiating 

 costae, decussated by closely arranged concentric lines ; the right valve smooth, its auricles 

 unequal, obtusely angulated and costated. 



It is only when the matrix consists of very fine sediment that the surface markings 

 of this small and delicate shell can be distinguished ; it is consequently rarely obtained. 

 The specimens recorded by Goldfuss were found in the Inferior {eisenschussigen) Oohte 

 of Grafenburg and Besan^on. 



This species differs somewhat from the figure of Goldfuss, in having the longitudinal 

 striation on the ears more prominent. 



Localities. Minchinhampton and Bisley Commons in the Great Oolite; it occurs 

 also in the Inferior Oolite of the same district. 



Pecten arcuatus, Sow. Tab. I, fig. 18. 



Pecten arcuatus. Sow. Min. Con., t. 205, f. 5 — 7, 1818. 



— — ? Goldfuss. Petref., p. 50, t. 91, f. 6. 



? Var. of Pecten lens, Sow., fide Bronn and Phillips. 



Testd ovato-orbiculari, convexo-pland, aequivalvi, costellis radiantibus confertis, arcuatim 

 diver gentibus, liinc inde dichotomis, striis interstitialibus punctatis ; auriculis inaqualibus 

 costellatis. 



Shell ovately orbicular, slightly convex, equivalve, with radiating, depressed little ribs 

 closely arranged, diverging with a curvature and sometimes dichotomous, the interstitial 

 spaces punctuated ; auricles unequal, ribbed. 



The radiating ribs are moderately broad, but much depressed, and undulate rather 

 irregularly where they are crossed by the few concentric folds of growth. This species 

 occurs rarely in the shelly beds of the Great Oolite. 



Localities. Bussage or Bisley Common ; Stonesfield, Oxfordshire. 



Pecten lens, Sow. Tab. II, fig. 1, \a. 



Pecten lens, Sow. Min. Con., t. 205, f. 2, 3, 1818. 



— — Goldfuss. Petref., p. 49, t. 91, f. 3. 



— — Zieten. Wurtt., p. 69, t. 52, f. 6. 



— — UOrb. In Murch, Russia, &c., ii, p. 4/6, t. 42, f. 1, 2. 



— — Quenstedt. Wurtt., pp. 337, 538, 544. 



— — Bronn. Leth. Geog., p. 206, t. 19, f. 7. 

 ? Pecten annulatus. Sow. Min. Con., t. 542, f. 1. 



— — Goldfuss. Petref.,' p. 49, t. 91, f. 2. 



