ANTHRACOMYA LiEVIS ; Var. 123 



and Naiadites (Anthracoptera) ; and, indeed, in perfect examples there is a striking 

 resemblance. I rely principally on the position and shape of the umbones, which 

 are almost terminal and pointed forwards in Naiadites. 



This shell occurs in very large numbers closely packed and all crushed fiat in 

 the black bands and ironstones of the Upper Coal-measures of North Staffordshire, 

 and here to the exclusion of all other molluscs. 



Professor T. Rupert Jones, F.R.S., who appears to have been the first to figure 

 this shell (" On some Bivalve Entomostraca from the Coal-measures of South 

 Wales," toe. supra cit.), draws attention to the resemblance in shape between some 

 of the Carboniferous Estherige and the genus Anthracomya. 



15. Anthracomya LiEvis, var. scotiua, Dawson,. Plate XVI, figs. 17 — 20, 42, 43. 



? Unio rttgulosus, Phillips. Murchison's Sil. Syst., p. 88, 1839. 

 ? Cardinia Feeystenii, 1 Geinitz. Die Versteinerungen de Steinkohlenforrnation in 



Sachsen, pi. xxxv, fig. la, a, 1855. 

 Naiadites ljevis, Dawson. Acadian Geo]., 1st edit., 1860 ; 2nd edit., p. 204, 



fig. 41, 1S68. 

 Anthracomya (Naiadites) l^vis, Salter. Quart. Journ. Geol. Soc, vol. xix, 



p. 79, fig. 2, 1863. 

 ? Anodonta obstipa, Ludwig. Pala?ontographica, Bd. x, p. 22, pl.iii, figs. 2, 2 a— f, 



1863. 

 Anturacomya Scotica, R. Etheridge,jun. Geol. Mag., dec. 2, vol. iv, p. 244, 



pi. xii, fig. 8, 1877. 

 L.EVIS, Hind. Quart. Journ. Geol. Soc, vol. xlix, p. 264, pi. x, 

 fig. 31, 1893. 

 _ _ _ Ibid., vol. 1, p. 441, pi. xx, fig. 12, 1894. 



Specific Characters. — Shell obliquely broad-ovate. Dorso-ventral and antero- 

 posterior diameters almost equal, hitherto only known as flat and compressed. 

 The anterior end is short and pointed, its border is rapidly produced downwards 

 and forwards in a curve to join the lower border, which is with the lower part of 

 the posterior border almost circular. The posterior end is flattened and pro- 

 duced ventrally. The border is rounded below, but almost straight above, and 

 obliquely truncate from above downwards. The hinge-line is straight, not quite 

 as long as the transverse diameter of the shell ; posteriorly the hinge-line forms an 

 obtuse angle with the posterior border. The umbones are anterior, not terminal. 



The interior is unknown. 



1 Professor Geinitz writes me that he now considers this shell to be an Estheria. See ' Sitz. Isis,' 

 1879, No. 1, p. 10. 



