214 



CRETACEOUS LAMELLIBRANCHIA. 



Janira quadrirostata, and many later writers have followed d'Orbigny in referring 

 that form to Sowerby's species ; but it was shown by Pictet and Campiche, and 

 also by Briart and Cornet, that d'Orbigny's species is distinct from Sowerby's. 

 The latter differs from the former in being of larger size, in having much larger 

 ears and a longer hinge-line, in the anterior and posterior areas sloping outwards, 

 in the larger apical angle (seen especially in the left valve), and in the greatest 

 length of the left valve being above the middle line. The Senonian form figured 

 by d'Orbigny was named Janira Faujasi by Pictet and Campiche, 1 and is regarded 

 by Choffat 2 as identical with regularis of Schlotheim. 



Fig. 5. — Pectcn (Neithea) quadricostatus, Sow. Upper Greensand, Warminster. York Museum. 

 Interior of left valve. Natural size. 



Types. — The specimens figured by Sowerby are in the British Museum — fig. 1 is 

 from the Upper Greensand of Haldon, fig. 2 from the Upper Greensand of Chute 

 Farm, Warminster. The example figured in the 'British Mineralogy' is from the 

 Upper Greensand of Stourhcad. 



Distribution. — Upper Greensand (zone of Schloenbachia rostra ta) of Blackdown 

 and the Isle of Wight; Upper Greensand (zone of Pecten asjper) of Haldon, Cerne 

 Abbas, Melcombe Bingham, Eggardon Hill, Maiden Newton, Ballard Down 

 (Swnnage), Warminster, and Ventnor. 



Pecten (Neithea) sexcostatus, Woodward, 1833. Plate XL, figs. 10 — 15; Plate 



XLI, figs. 1—10. 



? 1822. Pecten quinquecostata ?, G. Mantell. Foss. S. Downs, p. 128, pi. xxv, 



fig. 10. 

 ? - triplicata, Mantell. Ibid., p. 128, pi. xxv, fig. 9. 



1833. sexcostatus, S. Woodward. Geol. Norfolk, p. 48, pi. v, fig. 29. 



"Foss. Terr. Cret, Ste. Croix" (' Mater. Pal. Suisse,' ser. 5, 1870), p. 253. 

 ' F.mne Cn't, Portugal,' rol. i. ser. 4 (1901-2), p. 149. 



