150 MESSES. A. J. JUKES-BROWNE AND W. HILL : [May 1896, 



Pecten Dutemplei, d'Orb., and Pecten Galliennei, d'Orb. 



These are two of the species which have gone by the name of 

 interstriatus in England. P. Dutemplei is described by d'Orbigny 

 as having plain narrow ribs between the larger ornamented ribs, 

 and as having its ears marked only by vertical lines of growth, 

 P. Galliennei he describes as wanting the intermediate ribs and as 

 having several strong radiating ribs on the buccal ear. The first 

 is supposed to be confined to the Gault (Albien) and the second to 

 the Cenomanian. We do not feel certain that the latter is more* 

 than a variety of the former, or that they are confined to separate 

 stages. M. Bizet has sent us a specimen from the Cenomanien of 

 Condrecieux which he calls P. Galliennei, though it has the inter- 

 mediate ribs of Dutemplei. Specimens from La Heve, Warminster, 

 and the Cenomanian of Devon do, however, agree better with Gal- 

 liennei, and we have therefore so named them. 



Pecten Passyi, d'Arch., Mem. Soc. geol. Fr. ser. 2, vol. ii. p. 309, 

 pi. xv. fig. 9. 



This is a fossil from the Tourtia of Tournay, and has a consider- 

 able resemblance to P. Galliennei, d'Orb., but is described as having 

 perfectly straight, regular, and plain ribs, without any scales or 

 nodulations. The interspaces are striated in the usual manner. 

 Mr. C. J. A. Meyer has specimens which possess these characters 

 from his Bed 11, Dunscombe Cliff. 



Pecten subinterstriatus, d'Arch., Mem. Soc. geol. Ft. ser. 2, vol. ii, 

 pi. xv. fig. 10. 



Specimens which agree with the figure and description of 

 d'Archiac occur in the Cenomanian of Devon. It is distinguished 

 from the other interstriate species by its more numerous ribs, which 

 are in low relief and are crossed by fine concentric lines of growth, 

 each line where it crosses a rib developing a small short scale r 

 These scales are much more numerous and much less prominent 

 than those of P. Galliennei ; they are most strongly marked on the 

 anterior portion of the shell, and are mere slight ridges on the central 

 ribs. The ears are plain or marked only by vertical lines of growth ; 

 the anterior ear is much larger than the posterior. 



D'Archiac figures only a right valve, and, as Leymerie only figured 

 a left valve of his P. interstriatus, d'Archiac cautiously remarks that 

 his specimen may be only a right valve of that species. We have, 

 however, a left valve -which is clearly that of subinterstriatus, the 

 only difference being that the ribs are rather fewer and placed at 

 less regular intervals. 



The P. subinterstriatus figured in Dixon's ' Geology of Sussex,' 

 pi. xxviii. fig. 19, is wrongly so named, but is doubtless the P. ere- 

 tosus of Defrance (non Goldf.), as stated on p. 386 of that work, this 

 P. cretosus being probably the same as P. nitidus, Mantell. 



