R. Etheridge, Jun. — Contributions to British Palceontology. 243 
bat in my former description of P. Sowerbii I noticed a number of 
fine lines to be seen in tbe substance of the shell rather tban on it, 
especially when the shell is held at an oblique angle. Through 
the kindness of Mr. A. Patton I am now able to figure this (Fig. 1). 
Mr. Meek further remarked on the presence of the v-strife nearly 
always on one valve only — a character particularly coinciding with 
our shell, and adds that the v-striae are possibly a “ sort of effort 
at internal markings, of a very different kind, but in some respects 
analogous to the internal costas of Amussium.” 
Genus Aviculopecten, M‘Coy, 1851. (Aunals Xat. Hist., vii. p. 171.) 
Aviculopecten papyraceus, Sow. Plate XII. Figs. 4 and 5. 
Obs. — I give a figure of one of several speeimens well preserved 
in a dark limestone from the English Lower Coal-measures. The 
extreme Variation in the ribbing of the same individual is remark- 
able. The flattened spaces between the primary ribs or ridges are 
sometimes plain, or subdivided by one large interpolated rib from 
the margin, which does not reach the beak, or by two smaller ribs 
which ultimately unite and become one. In the case of the last- 
named Variation, the two interpolated ribs are separated by a less 
space than separates each of them from its contiguous primary ribs. 
The speeimens before me are all left valves, and have the anterior 
ear ornamented with from five to six radiating ribs. The posterior 
margins of all but one specimen are rounded, and form, with the 
hinge-line, well-marked but obtuse angles. In the exception the 
posterior margin is slightly sigmoidally curved, and the posterior 
wing slightly pointed. 
Loc. and Horizon. — Lower Lomax, Burv by Bolton-le-Moor, 
Lancashire, in a dark limestone of the Lower Coal-measures. Coli. 
Mus. Pract. Geol., London. 
Genus Axthkacojiya, Salter, 1861. (Iron Ores of Great Britain ; 
Mems. Geol. Survey, p. 229.) 
Anthracomya Phillipsii, Williamson. Plate XII. Figs. 6 and 7. 
Unio Phillipsii , "Will., 1836: Phil. Mag. vol. is. p."35l. (Without description.) 
Unio linguiformis, Phillips, 1839 ; Murchison’s Silurian System, p. 88. 
Moäiola sp., Binuey, 1855 ; Mems. Lit. Phil. Soc. Manchester, 2nd ser., vol. sii. 
p- 221, note. (Without description.) 
Anthracomya Phillipsii, Husley and Etheridge, 1865 ; Cat. Foss. Mus. Pract. Geol. 
pp. 157 and 160. (Without description.) 
Jones, 1870; Geol. Mag. Yol. VII. p. 217, PI. IX. Figs. 
3 and 18. 
Sp. Chars. — Transversely-obliquely-oval, modioliform, elongated 
in the direction of the diagonal. Anterior end small, its margin 
rounded ; posterior end mach higher than the anterior, with a long 
obliquelv truncated margin, fonning by its union with the hinge-line 
an obtuse angle. Hinge-line straight, almost half the length of the 
diagonal of the shell ; ventral margin convex, becoming straight 
anteriorly and passing up obliquely to the anterior end, when, if 
continued to meet the dorsal margin in a direct line, a very acute 
angle would be formed. Beaks anterior, almost terminal, very 
