104 CARBONICOLA, ANTHRACOMYA, AND NAIADITES. 
5. Anraracomya LANcKoLaTA, Hind. Plate XV, figs. 11, lla. 
MoproLa LiTHODOMOTDEs (on the authority of R. Etheridge, sen.), Ward. Trans. 
North Staff. Inst. Min. and Mech. Eng., vol. x, p. 180, 
pl. i, fig. 11, 1890. 
ANTHRACOMYA LANCEOLATA, Hind. Quart. Journ. Geol. Soc., vol. xlix, p. 267, 
pl. x, figs. 18, 18 a, 1893. 
Specific Characters.—Shell very narrrow dorso-ventrally, much elongated 
transversely. Almond-shaped; dorsal and ventral margins parallel. The anterior 
end is much lower than the umbones ; short and convex, its upper border straight, 
but directed obliquely upwards, rounded below. The inferior border is straight 
for the anterior fourth of its length, then slightly sinuated, after which it is 
produced backwards and very slightly downwards, till it curves bluntly upwards, to 
pass gradually into the posterior border, which is acutely pointed at its centre by 
a descent of the superior end and rise of the inferior border. The hinge-line is 
straight, extending about four-fifths of the length of the shell, not raised 
posteriorly. ‘he umbones are small, only just raised above the hinge-line, not 
contiguous, situated at a point one-sixth the length of the shell from the anterior 
end. The lunule is narrow and elongated. The shell is moderately convex in its 
anterior two-thirds, being gradually flattened above, below, and posteriorly in the 
hinder third. ‘There isa well-marked constriction, becoming broader and shallower 
towards the inferior margin, which it indents, in the anterior part of the shell, and 
an almost obsolete oblique ridge can be traced continuous with the upper border 
of the umbonal ridge towards the centre of the posterior end. 
Interior.—The surface of the cast is smooth. Anterior adductor scar marginal, 
large ; posterior scar not apparent. 
Heterior.—Surface covered with fine lines and flattened laminz of growth 
which are parallel to the inferior and posterior margin, and therefore sharply 
angulated or curved behind, before they pass upwards and forwards to terminate 
in the upper border. 
Measurements.—The type specimen measures— 
Antero-posteriorly : : A . 32 mm. 
Dorso-ventrally ° : =. 10 mime 
Laterally . ‘ = 7 mim. 
Locality.—Horizon uncertain. The type specimen was given me by a collier, 
who stated that he had picked it up at the Glebe Colliery, Fenton, where a 
number of seams in the Middle Coal-measures are worked. 
