502 EEV. a. E. WHIDBOENE ON SOME FOSSILS" 



Pecten spinicostates, Eth. MSS., n. sp. Plate XV. figs. 14, 14a. 



Shell orbicular, very convex, equilateral. Umbo direct, very 

 prominent, raised, large, and bluntly rounded. Kidges above wings 

 very distinct, short, very low, and concave. The other margins 

 almost evenly circular, except that they are crenulated by the pro- 

 jecting furrows, meeting the horizontal plane at an angle of about 

 45°. Surface evenly convex, but slightly produced and flattened on 

 the anterior side. The anterior ear very large and acutely triangular, 

 with five or six large and very coarsely corrugated rays or ribs. 

 The right valve covered with about forty-five very steep ribs, flat 

 and smooth on the tops, bearing a row of distant, regular, oblique 

 spines on each side, close to the flattened summits. The furrows 

 slightly narrower than the ribs, covered with close, fine, distinct, 

 thread-like concentric lines, which are concave to the umbo. 



Locality. Dundry. One specimen in the British Museum ; several 

 in that of the Bristol Institution. I have collected several from 

 the beds above the Ironstone Oolite, belonging to the higher part of 

 the Humphriesianus-zone ; but in most cases these fossils are much 

 injured, showing that it was probably a fragile shell. 



Dimensions of each Valve. 13 lines in length, 12 in width, and 

 about 5 in depth. 



This shell approaches Pecten globosus, Quenst. Jura, p. 757, Pecten 

 cardinatus, Quenst. Jura, p. 627, and P. moreanus, Buvignier, Meuse, 

 t. 19. figs. 18-20, which are all similarly decorated. 



Erom the first it appears to differ by having fewer and coarser 

 rays ; from the second by having the furrows broader and the ray- 

 teeth blunter and more distant; and from the third by not having these 

 side ornamentations raised above the level of the rays. It also ap- 

 pears to have a less developed or produced umbo than the two former 

 shells ; Thurmann and Etallon give a better figure of P. globosus, 

 Quenst. All these species seem to be more globose shells, with more 

 depressed umbones than the British species. P. erinaceus, Buvignier, 

 Meuse, t. 19. figs. 7-12, is a flatter shell, and has a third row of 

 spines on each rib. The foreign species occur in the Middle and 

 Upper Oolites. 



The small group of Pectens to which this shell belongs are very 

 distinct, being all more or less convex, and having the ribs marked 

 by rows of very beautiful spines or teeth, which are clearly not due 

 to fossilization. They differ from the group to which P. articidatus 

 belongs by the ribs being much more flattened on the top. 



Pecten teieoemis, n. sp. Plate XYI. fig. 3. 



Shell large, moderately convex, inequilateral, suborbicular. Um- 

 bones large, direct, rather produced. Superior part of posterior side 

 more enlarged than anterior. Surface covered with fine, parallel, 

 sharply zigzagging lines in the central part ; beyond these with very 

 fine close excentric radiating striae ; and in the marginal parts with 

 distant thread-like concentric lines or annuli, which present a frill- 



