108 CARBONICOLA, ANTHRACOMYA, AND NAIADITES. 
7. AnTHRAcomyA pumiLA, Salter. Plate XVI, figs. 2, 3, and 40. 
AnTHRACOMYA PuMILA, Salter. ‘Iron Ores of South Wales,’ p. 230, pl. ii, 
fig. 10, 1861. 
Non — — Hind. Quart. Journ. Geol. Soe., vol. xlix, p. 269, pl. x, 
figs. 17, 19, 28, 29, 1893. 
CARINATA (pars), Hind. Ibid., p. 273, pl. x, figs. 16, 16a. 
Specific Characters—The shell is transversely oblong, only slightly convex. 
The hinge-line and ventral margins are almost straight and nearly parallel. The 
umbones are small with depressed non-contiguous apices, situated within the 
anterior third of the hinge-line; the lunule is narrow and elongate. The anterior 
end is short, and somewhat pointed at its anterior superior angle. The posterior 
end is bluntly rounded or truncate. There is an obtuse diagonal ridge which rises 
in the umbones, and passes backwards and downwards to the posterior inferior 
angle of the shell, above which the shell is compressed so as to become slightly 
concave and expanded upwards into the posterior hinge-line. 
The Interior is not exposed in any of the specimens from South Wales. 
The Hxterior.—The surface is covered with striz and lines of growth, more 
marked and rugose at the ventral border ; periostracum wrinkled. 
Dimensions.—Fig. 2, Pl. XVI, measures— 
Antero-posteriorly ; : 2 2 liam: 
Dorso-ventrally , : j ; 8 mm. 
From side to side : 2 5 mm. 
Locality.—Mine over Three-quarter coal, No. 6 pit, Victoria, South Wales 
Coal-field, and at Merthyr Tydvil. 
Observations.—This species is at present only known from the bed above the 
Three-quarter coal of South Wales, which was the locality whence the original 
specimens described by Mr. Salter were obtained. It is just possible that the 
specimens I am able to figure, by the courtesy of the authorities of the Cardiff 
Museum, are the originals, as they have in their possession the collection of the 
late Mr. Adams, which Mr. Salter states contained his type. 
This species differs materially from any of the forms in North Staffordshire 
that have come to my knowledge, being much more compressed than A. Williamsoni 
and much more elongate than A. minima, the latter being the typical shell in the 
Knowles ironstone, which Mr. Salter gave as the horizon for A. pumila. 
In my paper on the ‘ Affinities of Anthracoptera and Anthracomya,” ‘ Quart. 
Journ. Geol. Soe.,’ vol. xlix, p. 269, I doubtfully referred some young specimens 
of A. Williamsoni and A. pulehra to this species, but from a study of the series 
in the Cardiff Museum I have arrived at the conclusion that these forms are quite 
