CONOCARDIUM. 449 



The sliell might easily be mistaken for Edmondia if not well preserved. 

 Unfortunately none of my specimens are quite complete, and the peculiar boss, 

 posterior to the umbo, is not seen in any of them. Three specimens, in the 

 condition of casts, show a deep linear groove, which passes upwards from the 

 lower margin a little way towards the umbo ; but I have not been able to make 

 out whether it is a constant and distinctive character or not. 



De Koninck states that the test of this species is smooth. PI. L, fig. 19, 

 a larger shell than any he figures, shows fine but distinct concentric strite. 



C. paruida is more transverse than C. abbreviata, and much less gibbose ; these 

 species are, however, so different in every character that there is no likelihood of 

 any difficulty arising in the differential diagnosis. 



Family CONOOARDIID^. 

 Genus Conocardium, Broun, 1835. 



Aecites, Martm, 1809. Petri facf;i Derbiensia, p. 5. 

 Caedium, Soicerb//, 1815. Min. Coiitli., vol. i, p. 187. 

 BucARDiTES (pars), Schlotheim, 1820. Petrefactenkunde, p. 207. 

 Abca, Fleminff, 1828. Hist. Brit. Animals, p. 399. 

 Conocardium, Bronn, 1835. Lethsea Geoguostica, vol. i, p. 92. 

 Pleurokhvnchus, Phillips, 1836. Geo!. Torks., pt. 2, p.»210. 

 LiCHAS, Steininger, 1837. Bull. Soc. Geol. France, ser. 1, torn, viii, p. 231. 

 Conocardium, Agassiz, 1840. Trad. Miu. Condi., pp. 123 and 5158. 

 Caedium, Goldfuss, 1841. Petrefact. Germauia?, pt. 2, p. 213. 

 CoNOCAEDiuM, Saiidberger, 1842. Neues Jahrb. Min., p. 397. 

 Caedium, de Koninck, 1842. Anini. Foss.Terr. Carbonif. Belg., p. 81. 

 Pleurorhyncuus, Portloclc, 1843. Eep. Geol. Londonderry, p. 440. 



— il/'Co!/, 1844. Carb. Limest. Foss. Ireland, p. 57. 



— Garner, 1844. Nat. Hist. StafFordsIiire, p. 452, pi. B, fig. 9. 



— Morris, 1845. Cat. Brit. Foss., p. 99. 

 Cardicm, de Verneuil, 1845. Geol. de la Russie, p. 301. 

 Conocardium, Keyserling, 184G. Petschoraland, p. 258. 

 PiiEUEOEHYNcnus, Broivn, 1849. Foss. Conch., p. 201. 



— F. A. Bihner, 1850. Geol. Nordwest. Harzgebirges, Pala;onto- 



graphica, vol. iii, p. 30. 

 Conocaruium, d'Orhigng, 1850. Prodrome Paleontol., vol. i, p. 131. 



— de Koninck, 1851. Anim. Foss. Terr. Carbonif. Belg. Supplement, 



p. 676. 



— Morris, 1854. Cat. Brit. Foss., edit. 2, p. 194. 



— M'Cog, 1855. Brit. Pal. Foss., p. 516. 



— Bronn and Romer, 1856. Lethaea Geognostica, vol. i, p. 419. 



— Woodward, 1856. Manual of MoUusca, p. 292. 



58 



