282 CRETACEOUS LAiyiELLIRRANCHIA. 



1872. iNOCEEAMrs LAiiiATUS, H. B. Geinitz. Das Ell)thalt|;fb. in Saelisen (Pal- 



oeontoijrapliica, vol. xx, pt. 2), 

 p. 46, 1)1. xii, fi;,'8. 1 — 3. 



1873. — — Geinitz. Neiies Jalirb. fiir Mill , etc., p. 13. 

 1877. — — C. SchllHer. Pala-outographica, vol. xxiv, p. 2(;2. 



— • — — A. Fritsch. Slucl. ini Grt-bieto der Ijiilmi. Krcide- 



forniat. ii, Weisspiibcr^'. \\. Malnitz. 

 Sc'hicht., p. 130, fig. 112. 

 ^ 1888. — — -S'. Nilitiii. Les Vestiges Cn't. Euss. eentrale 



(Mum. Coniite gt'ol. Euss., vol. v, 

 no. 2), p. 34, pi. 5, figs. 10, 11. 

 1888. — —A. Peron. Hist. Terr, de Craie daus le S.E. du 



Bassiu Anglo-Parisien, p. 158. 

 1893. — — F. Mirlinel. Zeitsclir. der deutsch. geol. Gesellsch., 



vol. xlv, p. 241. 



— — - T. W. Stn)iton. The Colorado Fonnatiou (Bull. 



U.S. Geol. Surv., No. 106), p. 

 77, pi. X, fig. 4 ; pi. xiv, fig. 2. 

 ? 1897. — —It. Leonluinl. Kreideforiuat. iu Ober.schles. (Pal- 



fBoutograpbica, vol. xliv), p. 48. 

 1903. — — TI^. Pftrasfhvcl: Jalirb. d. k. k. geol. Eeich.^au.st., 



vol. liii, p. 1,'J6. 



? Nou 18C8. - MYTihoiDES, E. Ficliwuld. Letlia?a Eossiea. vol ii, p. 492, pi. 



xxi, fig. 6. 

 -— 1881. — (Mttilites) rROBLEMATicus, R. Etheridije. In Penning and 



Jukes-Browne, Geol. Cambridge, 

 p. 143, pi. iii, figs. 9— 11. 



De.'tcripfinn. — Shell inytiliform, nearly cquivalve, extremely inequilateral, 

 oblique, much elongated between the umbo and the postero-ventral extremity, 

 convex, with a small posterior ear ; aiitero-dorsal part sloping steeply and some- 

 times concave. Angle formed by the hinge with the antero-dorsal margin about 

 90°. Umbones terminal, with a slight antei'ior curvature. Anterior margin gently 

 curved; postero-ventral extremity very convex; posterior margin nearly straight. 



Ornamentation consists of small, fairly regular concentric undulations, which 

 have an unsymmetrical curvature in the young, but become more nearly symmetrical 

 in older specimens. On the old i)arts of the shell the undulations become less 

 distinct. 



AflinificK. — It seems probable that this species is related to /. Crijijisi var. 

 rcachensis (p. 278), but the height of the shell is relatively greater, the length of 

 the hinge-line is less, and the direction of growth is oblique to the hinge-line. 



/. pwpiiupius, Goldfuss,' from the Quader-sandstone of Schandau, Avns regai'ded 

 by Geinitz as a sj'nonym of I. lahidiii.'i. 



1 ' Petref. Germ.,' vol. ii (1836) p. 112, jil. cix, fig. H. 



