Pecten. 



CONCHIFERA. 



155 



Tbo Kirameridge Clay, Brick Ilill, Boilfordshire ; the Middle 

 Oolite, Yorkshire :ind Brora; the Inferior Oolite, Glaizedale 

 and the Blue AVick. 



23. Pecten laminatus. — The Laminated Pecten, pi. LXII. 

 fig. U. 



P. laminaUi. Sowerby, III. p. 4, pi. 205, fig. 4. 



Sub-orl)ipular, compressed ; ears unequal, triangular, the 

 larger plaited ; surface with arcuated, slightly undulating 

 striic. 



The Cornbrash, Chatloy Lodge, Somersetshire. 



24. Pecten arciatu.s. — The Arcuated Pecten, pi. LXII. 

 fig. 15. 



P. arcuata. Sowerby, III. p. 4, pi. 205, figs. 5 and 7. 



Orbicular, compressed ; ears large, dissimilar, the larger 

 quadrangular and punctated; side of the shell below arcuated; 

 surface with arched, punctated, divergent stria3, and sometimes 

 with forked furrows. 



The Kimmeridge Clay, Aylesbury, and the Coral Crag, 

 CaJne. 



25. Pecten obsoletus. — The Obsolete Pecten, pi. LXIII. 

 figs. 4, 5, 6, & 7. 



P. obsoletus. Sowerby, VI. p. 79, pi. 541. 



Obovate ; ears very unequal ; surface with many divergent 

 ribs, varying considerably in number and development; in 

 some there are five or six broad obtuse ribs, with the interven- 

 ing furrows longitudinally striated ; others have furrows with 

 the flat parts striated ; while some are plain, with very minute, 

 nearly obsolete, longitudinal stria? ; in some sjiecimens the 

 lower margin is considerably inflected. 



The irammiferous Crag, Bramerton, and Red Crag, Sutton. 



26. Pecten axnulatus. — The Ringed Pecten, pi. LXIII. 

 fig. 9. 



P. annulatits. Sowerby, VI. p. 80, pi. 542, fig. 1. 



Orbicular, convex ; surface with numerous thin, erect, con- 

 centric lamina;, about a line apart, crossed by many fine, close- 

 set, longitudinal stria), also passing over the ears, which are 

 rather large. 



ThU species has a consider-ible resemblance to P. cinctus, but is 

 much less inflated. 



The Oxford Oolite, Osmiugton, Dorsetshire, and the Corn- 

 brash, Felmersham Bedfordshire. 



27. Pecten gracilis. — The Slender Pecten, pi. LXIII. 

 fig. 11. 



P. gracilis. Sowerby, IV. p. 129, pi. 393, fig. 2. 



Orbicular, a little longer than wide, convex ; very thin and 

 slender ; with numerous small longitudinal ridges, every fourth 

 one being a little more elevated than the others, and these in- 

 ternally produce grooves which are more conspicuous than the 

 rest ; these are crossed by numerous close, elevated, sharp, 

 uniform, concentric strix, which are strongest near the mar- 

 gins ; ears unequal, and the margin entire. 



Tlie Red Crag, Sutton. 



28. Pecte.n viminkus. — The Wicker Pecten, pi. LXIII. 

 fig. 8. 



P. rimineus. Sowerby, VI. p. 81, pi. 543, figs. 1 & 2. 



Convex, somewhat longer than wide ; with about twenty 

 prominent longitudinal ribs, some of which are obscurely tri- 

 {mrtito towards the edge, all of them provided with close-set. 



thick, elevated scales, which are loss numerous on the left 

 valve. 



Some specimens aru furnished with small interTening riba. 



The Oxford Clay, Upware, Cambridgeshire, and in the 

 Coral Crag, lialton and Brora. 



29. Pecten in-euuicostatus. — The Unequal-ribbed Pecten, 

 pi. LXIII. fig. 3. 



P. iiuvquicostatus. Phillips, Geo. York, I. p. 101, pi. 4, 

 fig. 10. 



Nearly orbicular, smooth, with nine broad, flat, divergent, 

 unequal ribs, the four central ones considerably larger than 

 the others ; ears moderate, and nearly equal. 



The Coralline Oolite, Malton. 



30. Pecten nitidus. — The Shining Pecten, pi. LXIV. 

 fig. 2. 



P. nitidiis. Mautell, Geo. Sus. pi. 26, figs. 4, 9. Sowerby, 

 IV. p. 130, pi. 394, fig. 1. 



Obovate, shining, one valve convex, with numerous crenula- 

 ted ridges ; the other nearly flat, with as many almost smooth 

 ridges, with the interstices minutely striated transversely ; 

 ears nearly equal, and the margins entire. 



The Under Chalk, Lewis and Gravesend. 



31. Pecte.n jacob.eus. — The Jacobean Pecten, pi. 

 LXIV. fig. 3. 



P. jacohcvus. Sowerby, VI. p. 164. Brown, Recent 

 Conch. Brit. p. 71, pi. 25, fig. 5. 



Upper valve flat, depressed towards the beak, with about 

 sixteen longitudinally grooved, decussated, quadrangular, ele- 

 vated ribs ; lower valve with sixteen rounded, grooved ribs, 

 and the interstices transversely striated ; ears equal, rect- 

 angular, with decussated striw. 



The Coral Crag, Aldborough. 



32. Pecten jiaximu.s. — The Great Pecten, pi. LXIV. 

 fig. 17. _ 



P. maximus. Sowerby, VI. p. 164. Brown, Recent 

 Conch. Brit. p. 71, pi. 25, fig 1. 



Upper valve flat, depressed towards the beak, with from 

 fourteen to seventeen roun<lctl longitudinally striated, or groov- 

 ed ribs ; lower valve very convex, and longitudinally striated ; 

 the interstices between the ribs of both valves striated ; ears 

 rectangular, with decussated strite. 



The Coral Crag, Aldborough, and Pleistocene Marine For- 

 mation, Ayrshire. 



33. Pecten si.milis. — The Similar Pecten, pi. LXIV. 

 fig. 11. 



P. siinilis. Sowerby, III. p. 5, pi. 205, fig. 6. 



Sub-orbicular, compressed, with longitudinal arched stri» ; 

 one ear larger than the other, with the side straight beneath 

 it ; sides nearly straight. 



The Coral Crag, Shotover, Oxfordshire. 



34. Pecten nitiiDUs. — The Rigid Pecten, pi. LXII. fig. 10. 

 P. rigiJa. Sowerby, III. p. 5, pi. 205, fig. 8. 

 Orbicular, compressed ; binge-lino triangular; ears unequal, 



large ; surface with strong longitudinal stria;, and slender, ir- 

 regular, concentric stria'. 



The Forctt Marble, Ca.stle Comlie, Wiltshire. 



35. PixTEN opekcllakis. — The Lid-shaped Pectou, pi. 

 LXIV. fiff. 15. 



