28 CARBONIFEROUS LAMELLIBRANCHIATA. 



PosiDONOMYA TUBEECTJLATA, MoTTis, 1843. Cat. Brit. Foss., 1st edit., p. 118. 

 PosiDONiA Becheri, M'Coy, 1844. Synops. Carb. Foss. Ireland, p. 78. 



— LATERALIS, M'Goy, 1844. Ibid., p. 78. 



— siMiLis, M'Coy, 1844. Ibid., p. 79, pi. xii, fig. 2. 



— TTJBERCULATA, M'Coy, 1844. Ibid., p. 79. 



— r — 1844. Ibid., p. 79, pi. xii, fig. 3. 



— Becheri, Cummhig, 1848. The Isle of Man, App. Q, p. 356. 



— LATERALIS, Cwnimmg, 1848. Ibid., p. 356. 



— Becheri, Browii, 1849. 111. Foss. Conch., p. 168, pi. Ixi**, fig. 35. 



— tubeeculata. Brown, 1849. Ibid., p. 168, pi. Ixi**, fig. 34. 



— lateralis. Brown, 1849. Ibid., p. 168, pi. Ixi***, fig. 2. 

 PosiDONOMiA Becheri, d'Orbigny, 1850. Prodrome Paleont., vol. i, p. 138. 

 PosiDONOMYA Becheri, BrouH and Boemer, 1852-4. Lethaea G-eogn., p. 400, pt. i, 



pi. iii, fig. 10 a. 



— — Morris, 1854. Cat. Brit. Foss., 2nd edit., p. 180. 



— lateralis, Morris, 1854. Ibid., p. 181. 



— tuberculata, Morris, 1854. Ibid., p. 181. 

 Posidonia Becheri, M'Coy, 1855. Brit. Pal. Foss., p. 521. 



— — var. a titberculata, M'Coy, 1855. Ibid., p. 522. 



— lateralis, M'Coy, 1855. Ibid., p. 522. 



PosiDONOMTA Becheri, Woodward, 1856. Man. MoUusca, p. 417, pi. xvi, fig. 22. 



— — Eichwald, 1860. Lethaea Eossica, vol. i, p. 942, pi. xxxvii, 



fig. 14. 



— — Baily, 1875. Figs. Char. Brit. Foss., p. 114, pi. xxxi.x, 



fig. 4. 



— — Boemer, 1876. Lethaea Palseoz., taf. xxxviii, figs. 2 a — c. 



— — Bigshy, 1878. Thesaurus Devonico-Carbonifenis, p. 293. 



— lateralis, Bigshy, 1878. Ibid., p. 293. 



— TUBERCULATA, Bigsby, 1878. Ibid., p. 293. 



— — von Koenen, 1879. INeues Jahrbuch Min. Geol. Pal., 



p. 334, pi. vi, fig. 8. 



— — Fischer, 1887. Man. de Conchvliologie, p. 959, pi. 



xvi, fig. 22. 



— — Etheridge, 1888. Brit. Foss., pt. 1, Palaeozoic, p. 276. 



— LATERALIS, Etheridge, 1888. Ibid., p. 276. 



— SIMILIS, Etheridge, 1888. Ibid., p. 276. 



— TUBERCULATA, Etheridge, 1888. Ibid., p. 276. 



Specific Gharacter>i.— Shell of medium size, expanded and somewhat compressed, 

 obliquely subovate, obliquely pectiniform. The anterior border is well rounded, 

 and forms a blunted angle with the hinge-line. It curves dowuAvards and backwards, 

 and passes with a continuous sweep round the lower border with a gradual 

 increase in the degree of convexity till, passing round into the posterior border, 

 the convexity again becomes greater. The posterior border is almost straight for 

 the greater part of its extent, and forms a well-marked obtuse angle with the 

 hinge-line. The hinge-line is straight, much shorter than any other transverse 



