228 CRETACEOUS LAilELLIBRAXCHIA. 



Panopea mandibcla iSowerhi/), 1813. Plate XXXVII, figs. 1—5. 



1813. Mta mandibtjla, /. Sowerby. Min. Conch., vol. i, p. 93, pi. xliii. 

 ? 1840. Panop.sa BArMONTii, A. Goldfuss. Petref. Germ., vol. ii, p. 274, pi. clviii, 



fig. 4. 

 ? 1841. — Jvaj^Eui, F. A. Rnmer. Die Verstein. d. nord-deutseh. Kreidegeb., 



p. 75. pi. X, fig. 4. 

 1845. — MANDiBULA, A. d'Oihlyiiy. Pal. Fran9. Terr. Crt't., vol. iii.p. 344, 



pi. cccls, figs. 3, 4. 

 1850. — — H. B. Geinifz. Das Quadersandst. oder Kreidegeb. 



iu Deutschland, p. 146. 

 1854. Mtacites mandibula, /. Morris. Cat. Brit. Foss., ed. 2, p. 213. 

 1865. Panopea — F. J. Piclef and G. Campiche. Terr. Crt't. Ste. Croix 



(Matt'r. Pal. Suisse, ser. 4), p. 70. 

 1870. — — J^. Stoliczl-a. Palaeout. ludica, Cret. Fauua S. ludia, 



vol. iii, p. 87. 

 1873. — — H.B. GeiiiUz. Das Elbthalgeb. iu Sachseu (Pal- 



aeontographica, vol. xx, pt. 2), p. 

 70, pi. xviii, figs. 20, 21. 

 ? 1883. — — A. Fritscli. Stud, im Gebiete der bohm. Kreide- 



forinat., iii, Iserschielit., p. 108. 

 ? 1897. — — Friisch. Ibid., vi, Chlomek. Sc-hiolit., p. 60. 



1900. Pi,EUBOMT.\ — A. J. JiiJces-Broicne. Cret. Eocks of Britain, vol. i, 



p. 470. 



Description. — Shell oblong or rliomboidal in outline, very inequilateral, 

 convex, anterior part sloping rapidlj^to the anterior margin, with a wide posterior 

 gape. Anterior margin somewhat convex ; antero-ventral extremity rounded ; 

 ventral margin straight or slightly curved and neai'ly parallel to the dorsal 

 margin; postero-A'entral extremity rounded ; posterior margin truncated, nearly 

 straight, either perpendicular or slightly oblique to the nearly straight postero- 

 ■dorsal margin. Unibones prominent, narrow, pointed, considerably incurved, 

 with a In'oad, .shallow furrow extending from their posterior side to the postero- 

 ventral i)art of the valves. In front of the umbones the shell is considerably 

 depressed. 



Ornamentation consists of strong, rounded, concentric folds, which become 

 less distinct in and posterior to the dorso-ventral furrow; and of radial rows of 

 minute granules. 



Measurements ; 



(1, 4 — 6) Upper Greensand, Veutuor. 

 (2, 3) Upper Greensaud, Devizes. 



