EDMONDIA MACCOYII. 329 



anterior muscle-scar is not in the position which obtains in that genus, though the 

 umbones are markedly prosogyrous. It is noteworthy that at least one species 

 of Cardiomorpha, C. eorrugata, M'Coy, has well-marked, broad, concentric grooves 

 and ridges (PI. XXIII, figs. 5 — 7). M'Coy's type specimen is preserved in the 

 Griffith Collection of the Museum of Science and Art, Dublin, and I reproduce it, 

 PI. XXXVI, fig. 20, by the kindness of the director, Dr. Scharff. It is a medium- 

 sized specimen, and was obtained from Millicent, Olane, co. Cork. M'Coy describes 

 it as being " transversely ovate, short, and very gibbose, anterior end obtusely 

 pointed ; " and it is difficult to understand why later on he referred a shell to this 

 species which he described as " oblong, short, very tumid, anterior end very small, 

 compressed, rotundato-quadrate." The two descriptions of E. scalar is by M'Coy 

 are so totally different, that there can be no doubt that he had a totally different 

 shell under observation when writing his later work. The type of his second 

 shell, in the collection of the Woodwardian Museum, Cambridge, was obtained 

 from Lowick. The same collection contains several other specimens from the 

 Carboniferous Limestone of Settle, which are certainly different from the Irish shell. 



Edmondia MacCoyii, sp. nov. Plate XXXVI, figs. 23—30. 



Edmondia scalauis, M'Coy, 1855. Brit. Pal. Foss., p. 502, pi. 3 h, iig. 6. 



— — (pars), Etlieridge, 1888. Brit. Foss., pt. 1, Palaeozoic, p. 284. 



Specific Characters. — Shell transversely subquadrate, very inequilateral, 

 gibbose. The anterior end is very short, rapidly compressed, and relatively deep 

 from above downwards. The anterior border, commencing above, makes blunted 

 right angle with the hinge-line, and descends downwards in an almost straight 

 line, becoming very bluntly curved below, where it passes into the inferior border, 

 which is itself but very feebly curved. The posterior border is truncate, almost 

 straight, joining the lower border with an obtuse curve, and forming a right angle 

 with the hinge-line above. The hinge-line is almost straight, produced posteriorly, 

 as long as any antero-posterior diameter of the shell. The umbones are compara- 

 tively large, tumid, incurved, and twisted forwards, contiguous, only slightly 

 elevated above the hinge-line, and situated in the anterior quarter of the shell. 

 The valves are regularly convex, but rapidly compressed above a line passing 

 from the umbo to the postero-inferior angle. There is no lunule or escutcheon. 

 The greatest convexity of the valve is at the junction of the upper and middle 

 thirds of the shell, a little in front of the middle of the valve. 



Interior. — The anterior adductor muscle-scar is placed in the anterior part of 

 the umbonal hollow, and is shallow but large and striated. The posterior scar 



