302 CARBONIFEROUS LAMELLIBRANCHIATA. 



Edmondia eudis, M'Ooy, 1851. Plate XXVIII, figs. 8—14. 



? Coebula? senilis, Phillips, 1836. Geol. Torks., pt. 2, p. 209, pi. v, fig. 1. 

 — ? — Morris, 184-3. Cat. Brit. Foss., 1st edit., p. 83. 

 Leptodomus senilis, M'Coy, 1844. Synops. Carb. Foss. Ireland, p. 67. 

 Caediomoepha senilis, cTOrbigny, 1850. Prodrome de Paleontol., p. 132. 

 Edmondia eudis, M'Coy, 1851. Ann. Mag. Nat. Hist., ser. 2, vol. xii, p. 190. 



— — Morris, 1854. Cat. Brit. Foss., 2nd edit., p. 202. 

 Leptodomus ? senilis, Morris, 1854. Ibid., p. 206. 



Edmondia eudis, M'Coy, 1S55. Brit. Pal. Foss., p. 502, pi. 3 f, fig. 9. 



— — Young and Armstrong, 1871. Trans. Geol. Soe. Glasgow, vol. iii, 



Supplement, p. 51. 



— — Armstrong, Young, and Robertson, 1876. Cat. Western Scottish 



Fossils, p. 54. 



— — Bigsby, 1S78. Thesaurus Devonico-Carboniferus, p. 307. 

 Leptodomus senilis, Bigsby, 1878. Ibid., p. 307. 



Edmondia eugata, de Koninck, 1885. Ann. Mus. Roy. d'Hist. Nat. Belgique, 



torn, xi, p. 31, pi. ii, figs. 1, 2. 



— unionifoemis, de Koninch, 1885. Ibid., p. 29, pi. ii, figs. 32 — 36. 



— eudis, Etheridge, 1888. Brit. Foss., pt. 1, Palaeozoic, p. 2S3. 

 Leptodomus senilis, Etlieridge, 1SS8. Ibid., p. 284. 



Specific Characters. — Shell subquadrate, somewhat transverse, gibbose, inequi- 

 lateral, slightly oblique. The anterior side is very short, abruptly compressed, 

 and its margin almost straight in the upper portion, but becoming curved in the 

 lower to pass into the inferior border, which is only very gently convex. The 

 posterior end is broader than the anterior, and is obliquely and very bluntly 

 curved, the upper and lower angles being obtusely rounded. 



The hinge-line is somewhat arcuate in front, but nearly straight and somewhat 

 produced posteriorly. 



The umbones are comparatively large and obtuse, their apices incurved and 

 twisted forwards, contiguous, raised above the hinge-line, and situated at about 

 the anterior fourth of the hinge-line. Passing backwards from the apex of the 

 umbo, and almost parallel to the hinge-line, is a well-marked ridge, becoming lost 

 near the posterior end, which separates a smooth, narrow, elongate hollow from 

 the dorsal slope. 



The valve is regularly convex from above downwards and strongly curved. 

 From before backwards the convexity is a little less than in the vertical diameter, 

 but there is an obscure approach to angulation along two lines before and also 

 behind, which pass from the umbo towards the anteroinferior and postero-inferior 

 angles respectively. The greatest convexity of the valve is a little above the 

 median transverse diameter. 



