114 CARBONICOLA, ANTHRACOMYA, AND NAIADITES. 
Dimensions.—Fig. 46, Pl. XVI, measures— 
Antero-posteriorly ‘ : . 6 mm: 
Dorso-ventrally (behind) : A Sayan. 
From side to side : . 4+mm. 
Locality.—Dalmeny railway-cutting, near Wester, Dalmeny. Lower Carbo- 
niferous of Scotland. 
Observations. —This little species has the characteristic shape of the genus. 
A set of fourteen specimens are in the Geological Survey Collection of Edinburgh, 
labelled A. Valenciensis, MS., R. Etheridge, jun., all from the locality stated 
above. This species appears to be the smallest and, at the same time, the 
earliest member of the genus known in Carboniferous times. I know of no other 
species which can be mistaken for it, as it is much more regularly globular than 
A. minima, unless it turns out to be the perfect form of A. levis, var. Scotica, which 
is only known in a much-compressed condition. 
12. ANTHRACOMYA PULCHRA, sp. nov., Hind. Plate XV, figs. 29—49. 
ANTHRACOMYA PUMILA, pars, Hind. Quart. Journ. Geol. Soc., vol. xlix, 1893, 
p- 269, pl. x, figs. 28 and 29. 
Specific Characters.—Shell transversely oblong, convex, at times almost 
cylindrical. The anterior end is compressed, and has its border almost circularly 
curved, the posterior superior angle not being prominent. The upper border of 
the anterior end is much below the level of the umbones. The inferior border is 
straight or shghtly concave, joining the anterior border by an abrupt curve, 
while posteriorly it forms a more or less obtuse angle with the obliquely truncate 
posterior border, so that the posterior inferior angle is well marked and somewhat 
acute, and this point is the most posterior portion of the shell ‘The hinge-line is 
straight, deviating very slightly from parallelism with the ventral edge. The 
umbones are obtuse, gibbose, almost contiguous, and raised above the hinge-line. 
They are situated anteriorly at a point distant from the anterior end equal to about 
one-fifth the length of the hinge-line. The umbones are excavated in front by a 
well-marked lunule, and posteriorly there is a well-marked escutcheon or groove 
on each side of the external ligament, which is erect, and small and short. The 
posterior or greater portion of the shell is convexly swollen in an oblique direction 
from the umbo to the posterior inferior angle. The compression anterior to the 
ridge, characteristic of this genus, is only seen at the lower edge of the shell, about 
the centre, as an almost obsolete broad sulcus. Above the swelling the shell is 
