338 CRETACEOUS LAMELLIBRANCHIA. 



diverging and distinctly curved ribs. /. digitatus appears to be closely allied to 

 J. subcardissoides, Schli'iter. 



Type. — From the Drift (derived from the Chalk) ; locality unknown. In the 

 British Museum, No. 43,273. 



Distribution. — No undoubted specimens obtained directly from the Chalk have 

 been seen. 



Inoceramus pinniformis, WiUett, 1871. Text- fig. 96. 



1871. Inoceramus pinniformis, H. WiUett. Cat. Cret. Foss., Brighton Mus., 



p. 40, 110. 342. 



Description . — Shell very large, much higher than long, of moderate convexity, 

 Avith a posterior wing-like part. 



Ornamentation consists of broad, strong, widely separated concentric folds 

 which have a nearly symmetrical curvature ; the ventral slopes of the folds are 

 rather steeper than the dorsal ; in the interspaces are small (sometimes indistinct) 

 concentric folds, which give a more or less marked tuberculate character to the 

 radial ribs. The latter are rounded, rather numerous, sometimes partly or com- 

 pletely divided by a median furrow, and are continued on to the dorsal surfaces 

 of the strong concentric folds, but are absent or indistinct on the ventral surfaces. 



Remarks. — A portion of a large Inoceramus named L pinniformis by Willett 

 resembles I. subcardissoides, Schli'iter, 1 but differs from that species by the more 

 numerous radial ribs and the absence of a broad furrow extending from the umbo 

 in a postero-ventral direction. 



Tijpe. — In the Brighton Museum. 



Distribution. — Upper Chalk (zone of Actinocamax quadratus) of Brighton, and 

 three miles east of Sled mere, Yorkshire. 



1 ' Palaeontogranbica,' vol. xxiv (1877), p. 271, pi. xxxvii ; Barrois, 'Aim. Soc. gcol. Nord.,' 

 vol. v (1878), p. 474; Wollemann, ' Liineburg. Kreide ' (1902), p. 70; Wegnpr, ' Zeitschr. d. 

 deutsch. geol. Gesellsch.,' vol. lvii (1905), p. 169; /. Gosseleti, Dococq, 'Assoc. Frauc. A vane. Sci.,' 

 1874 (1875), p. 371. 



