306 CARBONIFEROUS LAMELLIBRANCHIATA. 



Edmondia primjeva, Portloclc, sp., 1843. Plate XXIX, figs. 6—8; Plate XXX, 



figs. 1—3. 



Lutbaeia peim^ta, Portlock, 1843. Geol. Eep. Londonderry, p. 441, pi. xxxvi, 



fig. 5. 



— peisca, M'Coy, 1844. Synops. Carb. Toss. Ireland, p. 52, pi. xii, fig. 4. 



— prim^va, Morris, 1845. Cat. Brit. Foss., p. 90. 

 Cardiomokpha prisca, d'Orbigny, 1850. Prodrome de Pale'ontol., p. 133. 

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

 Mtacites? tenuilineata, Etheridge, 1873. Geol. Mag., vol. x, p. 299, pi. xii, 



fig. 7. 

 Edmondia tenuilineata, Bigshy, 1878. Thesaurus Devonico - Carboniferus, 



p. 307. 

 Cardiomorpha tenuilineata, Bigshy, 1878. Ibid., p. 301. 

 Lutraria tenuilineata, Etheridge, 1885. Brit. Foss., pt. 1, Palaeozoic, p. 285. 

 Mtacites prim^va, Etheridge, 1885. Ibid., p. 286. 



Broeckia prisca, de Koninch, 1885. Ann. Mus. d'Hist. Nat. Belgique, torn, xi, 



p. 20, pi. ii, figs. 14, 15. 



— latissima, de Koninch, 1885. Ibid., p. 20, pi. ii, fig. 13. 



— Katseri, de Koninch, 1885. Ibid., p. 25, pi. v, figs. 13, 14. 



— normalis, de Koninch, 1885. Ibid., p. 22, pi. v, figs. 3, 15, 16. 



Specific Characters. — Shell ovate, transverse, moderately convex, very inequi- 

 lateral. The anterior end is small, but deeper in the dorso-ventral diameter than 

 the posterior, its border regularly rounded, passing with a continuous sweep into 

 the inferior margin, which is convex and extended. The posterior border is 

 narrowed by the approach of the upper and lower margins, and is bluntly rounded. 

 The hinge-line is long and gently arched, somewhat depressed posteriorly. The 

 umbonesare large, elongated, incurved, and slightly twisted forwards, contiguous, 

 elevated, and situated in the anterior fourth of the valve ; well marked off in 

 front from the compressed antero-superior angle, but behind they are continuous 

 with the general curvature of the valve. The dorsal slope is not marked off 

 from the rest of the shell. The upper margin is simple and erect, and comes in 

 contact with its fellow. There is a small elongate groove for the external 

 ligament for a short distance between the umbonal swellings. Xo escutcheon or 

 lunule. 



Interior. — The anterior adductor muscle-scar is shallow and placed high up. 

 The posterior is oval and is situated within the dorsal slope, remote from the 

 posterior end. The pallial line is entire. The hinge is edentulous, with a 

 curved ridge of shell situated some little distance within the margin, represented 

 in casts by a groove. 



The Exterior. — The surface is ornamented by concentric lines, fine, distinct in 



