58 CARBONICOLA, ANTHRACOMYA, AND NAIADITES. 
it; in the left valve a split cardinal tooth, which receives between its two halves 
the tooth of the opposite valve; anterior and posterior laterals are absent. In the 
figure will be noticed a faint oblique line on the posterior part of the hinge-plate, 
which, with a similar occurrence in Pl. VI, fig. 2, are the only indications of 
horizontal lateral teeth that I have met with. Pl. V, fig. 38, contains a small 
pearly nodule, well shown at ‘‘a”’ in the drawing. 
That this form of hinge-plate (y) is not confined to C. ovalis is certain, I think, 
from the occurrence of a similar form in specimens having the typical shape of 
C. acuta. 
Prof. Amalizky* has referred a new species of his, named Anthracosia subnucleus, 
from the Permian formation of the Oka Volga Basin, as allied to the forms— 
U. ovalis, Martin; U. centralis, Sow.; U. uniformis, Sow.; U. nucleus, Brown; 
and U. ovalis, Salter. Judging, however, from the figures, dimensions, and 
description, his shell is totally different from the form under discussion, and I 
have shown above that the forms referred to are themselves very different, one of 
them being from the Oolite. 
Localities England: Tupton Moor and Staveley. Roof of the Cockshead 
Seam and the Cockshead Rock, Lower Coal-measures of North Staffordshire. 
Pennystone Beds, White Flats, Blue Flats—Coalbrookdale. Butterley, Leicester- 
shire. Old Coal, South Wales. Scotland: Kenmuir and Clyde Pits, Lanarkshire 
Coal-field. 
5. CaRBONICOLA PoLtmonTENsIS (Brown). Pl. VII, figs. 1—4. 
Unto (from Coal-shale), Rhind. Age of the Earth, pl. ii, figs. c, p. 
— Poxmontensts, Brown. Foss. Conch., pl. Ixxiii, figs. 32, 33. 
Specific Characters.—Transversely elongate-oval ; sides flatly convex. Umbones 
are much elongated transversely, narrowed, apart, and everted anteriorly, situated 
at two-fifths of the length of the shell from the anterior end, which is rounded. 
The posterior end is compressed and bluntly pointed. The hinge-line is straight, 
and in casts median. The interior of the shell shows fine striz radiating from the 
umbones to the surface. Posterior slope obtusely rounded; upper surface 
expanded. There is an oblique, shallow, broad depression on the sides of the 
shell, most marked towards the posterior part of the inferior border. External 
characters unknown. Muscular scars normal. Pallial line not very far from the 
margin of the shell. 
1 « Paleontographica,’ vol. xxxix, 1892; ‘ Ueber der Anthracosien die Perm-formation Russlands,’ 
156, pl. xx, figs. 19, 20. 
