328 CRETACEOUS LAMELLIBRANCHIA. 



1850. Inoceramus involutus, J. de C. Sowerby, in F. Dixon. Geol. Sussex, p. 



355 (p. 386, ed. 2), pi. xxviii, fig. 32. 

 1854. J. Morris. Cat. Brit". Foss., ed. 2, p. 169. 



1863. — — A. v. Strombeck. Zeitscbr. d. deutsch. geol. 



Gesellscb., vol. xv, p. 127. 

 1871. (Yolviceramus) involutus, F. StoliczJca. Palaeont. Indica, 



Cret. Fauna S. India, vol. 

 iii, pp. 394, 401. 



1875. involutus, C. Decocq. Assoc. Franc. Avanc. Sci. (Lille, 



1874), p. 367. 



1876. — J). Brawns. Zeitscbr. f. d. gesammt. Naturwiss., 



vol. xlvi, p. 379. 



1877. — — C. Sehlilter. Palseontograpbica, vol. xxiv, p. 272. 



1878. — C. Barrois. Ann. Soe. geol. du Nord, vol. v, 



p. 475. 

 1888. (Volvice ramus) involutus, G. Midler. Jalirb. d. k. preuss. 



geol. Landesaust. fiir 1887, p. 411, 

 pi. xvi, figs. 3, 4. 

 involutus, A. Peron. Hist. Terr. Craie S.E. du Bdssin 



Anglo-Parisien, p. 157. 



1901. F. Sturm. Jalirb. d. k. preuss. geol. Landesanst. 



fiir 1900, vol. xxi, p. 91, pi. ix, tig. 4. 



1902. — A. Wollemann. Liineburg. Ivreide (Abbandl. d. 



k. preuss. geol. Landesanst. 

 n.f., 37), p. 68, pi. i, tig. 4; 

 pi. ii, figs. 7, 8. 

 1906. — G. Smolenslii. Bull. Intern. Acad. Sci. Cracovie, 



p. 721. 



1909. — J. Nowalc. Ibid., p. 874, pi. xlvi, figs. 4, 5. 



1910. — J. Bohm. Centralbl. fiir Min., etc., p. 741. 



Description. — Shell very inequivalve and very inequilateral. Right valve oval 

 or semi-oval in outline ; usually slightly convex, but sometimes either more convex 

 or nearly flat, with the marginal part in old specimens forming an obtuse angle 

 with the earlier part. Length greater than height. Anterior and ventral margins 

 rounded : posterior margin forming usually an obtuse angle but sometimes nearlv 

 a right angle with the hinge. Umbo usually inconspicuous, at or near the 

 anterior end of the hinge-line. Hinge-line equals about three-quarters of the 

 length of the valve. Postero-dorsal marginal part convex near the hinge and 

 separated by a sharp furrow from the remainder of the valve. Ornamentation 

 consists of strong, somewhat irregular concentric folds, with an unsvmmetrical 

 curvature; the folds are separated by broad, concave interspaces. In casts of this 

 valve, and sometimes in the shell itself, radial markings are seen in the concave 

 interspaces. 



Left valve much larger than the right, inflated, more or less considerably 



