INOCEKAMUS. 279 



Nou 18S5. Inoceramus convexur, J. JArZ/and F. /?. J/eei-. Foss. Cret. Nebraska (Mom. 



Amer. Acad. Arts and Sci , 

 vol. v), p. 386, pi. ii, fig 2. 



Description. — Valves nearly oqiial, considerably iiierniilateral, tiimirl, compressed 

 near the postero-dorsal mai'g'in ; lieit^lit greater than length. Antero-dorsal margin 

 nearly straight; ventral margin usually very convex ; posterior margin slifhtlv 

 or moderately convex, forming an ohtnse angle with the hinge-line. Anterior 

 marginal parts more or less nearly perpendicular to tlie plane of the valves, some- 

 times concave near the nmho. Uinbones terminal, curved inwards and forwards. 

 Angle between the hinge-line and the anterior margin is about 115°. The hei'dit 

 of the shell is nearly twice the length of the hinge. 



Ornamentation consists of faintly marked concentric undulations and numerous 

 growth-lines. 



Affinities. — In this species the antero-dorsal margin is relatively longer and 

 more nearly straight, and the postero-dorsal ])art of the shell less compressed thnn 

 in J. tenim, Mantell. 



J. conve<i-nii var. fpuidratus, Etheridge, "was founded on a specime]i in which the 

 antei'ior part of the shell is pressed in, giving rise to the appearance of a carina 

 at the upper margin of the antero-dorsal slope. 



Types. — From the Totternhoe Stone of Burwell, in the Sedgwick Museum, 

 Cambridge. 



Distnlivfion. — Upper Greensand (zone of I'erten a.^per) of "Warminster. 

 Cenomanian of Wilmington, Devon. Chalk Marl of Branscond)e, Beer Head, 

 Titherleigh (near Chan!) and Hunstanton. Totternhoe Stone (zone of Holastn- ' 

 siihgluhosii.'i) of Burwell. 



Inockpamis I'lrrrs, Soverhij, ^ 829. Plate XLIX, figs. 5, 0. Text-fig. 30. 



1829. JyocERAiivs vic'ivs, J. de C. Soverly. Min. Conch., vol. vi, p. 215, pi. dciv, 



fig. 1. 

 1854. — picTus, J. Morris. Cut. Brit. Foss., ed. 2, p. 170. 



1867. — ANGULATUS, E. Gvrraiiger. Album Pali'out. de la Sartbi', p. 



20, pi. XX V, fig. 7 (? I. ANQULATUS, 



trOiblyni,. 18-16). 

 J904. — picTvs, E. T. Kill h, II \uu\ A.J. Ji(J.-iif-Bioiriie. In Jukfs-Browue, 



Cret. Kocks of Britaiu, vol. 

 iii. p. 150. 



Jhscrij'tloii.—iihdl equivalve, very inequihiteial, slightly or moderately convex 

 with flattened sides; the postero-dorsal part compressed. Antero-dorsal marginal 



