/ 



338 CRETACEOUS LAMHLI/IHKAXCHIA. 



diverging and distinctly curved ribs. 7. di(/itafiis appears to be closelj' allied to 

 /. subcardissoide>^-, Sclili'itcr. 



Ti/))f. — From the Drift (derived from the Chalk) ; locality unknown. In the 

 British Museum, No. 43,273. 



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

 been seen. 



Inoceramus PiNNiFORMis, WiUetf, 1871. Text-fig. 96. 



1871. Inocekamus pinnifoemis, II. Willett. Cat. Giet. Foss., Brighton Mus., 



p. 40, uo. 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 moi'e 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. 



Bfrnarks. — A portion of a large Inoceramns named 7. pianifurmiti liy Willett 

 resembles 7. sulicardissoiiles, Schliiter,^ but differs from that species Ijy tlie more 

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

 in a postero-ventral direction. 



Ti/pi'. — In the Brighton Museum. 



DistribiUioit. — Upper Chalk (zone of Ai'tiiiocn imrr qHudrnfiis) of i'.rigliton, and 

 three miles east of Sled mere, Voi'kshire. 



• ' Palaeoutograiiliica,' vol. x\lv (1877). p. 271, jil. .xx.wii ; Baimi.s. ' Auu. Soc. gvol. Nord.,' 

 vol. V (1878), p. 474-; Wollt'inami, ' Luncbnr^r. Kreide' (1902), p. 70; Wegiinr, ' Zeitschr. d. 

 deutsuh. Kt'ol. GivscllsL-h.," vol. Ivii (liMl.")). p. 169; I. (t'oxho/c/i', Dccocq, 'Assoc. Franc. Avaiic Sci.,' 

 1874 (1876), p. 371. 



