PARALLELODON CINGULATUS. 137 



of a shell of medium size. A right valve, which is said to have served as the type 

 of M'Coy's figure, is also reproduced, PI. IX, fig. 11, by the kind permission of 

 Dr. Scharff, Director of the Science and Art Museum, Dublin, where it is 

 preserved in the Griffith Collection. This is a very small shell indeed, and it is 

 very probable that it is not the figured specimen at all; because, although the 

 figure at PL XIII, fig. 20, of M'Coy's work (ojp. sv,y. cit.) appears to be that of a 

 " right valve," yet, as in " The Synopsis " none of the drawings were reversed 

 on the stone, the original must have been a left valve, and the shell which I now 

 figure is that of a right valve, and only half the size of M'Coy's figure. 



Paeallelodon cingulatus, M'Coy, sp., 1844. Plate IX, figs. 1 — 4. 



Venerupis cingulatus, M' Coy, 1844. Synopsis Carb. Foss. Ireland, p. 67, pi. x, 



figs. 1 a, b. 

 Cypricardia cingulatus, cTOrb., 1850. Prodrome Paleont., vol. i, p. 130. 

 Venerupis cingulatus, Bigsby, 1878. Thesaur. Devonico-Carboniferus, p. 315. 

 — (vide Pullastka bistriata), Etheridge, 1888. Brit. Foss., 



part 1, Palseoz., p. 291. 



Specific Characters. — Shell inequivalve, the right valve being more convex and 

 higher than the left, gibbose, obliquely quadrilateral, produced posteriorly. The 

 anterior end is almost obsolete, compressed, narrow, overlapped above by the 

 umbones, which project forwards, and form the most anterior portion of the 

 valve. The anterior border is curved, and passes gradually into the inferior 

 border, which is directed obliquely downwards and backwards ; and, although 

 but gently convex downwards in front, becomes strongly so in the posterior two- 

 thirds, where it is curved upwards to join the posterior border, which is straight 

 and obliquely truncate from above downwards and backwards, becoming bluntly 

 rounded as it joins the inferior border. The hinge-line is straight, equal in 

 length to about two-thirds of the greatest (antero-posterior) diameter of the 

 valve, somewhat elevated posteriorly, where it joins the posterior border at a 

 very obtuse angle. The umbones are anterior, small, pointed, convex, curved 

 inwards and forwards, raised above the hinge-line, and the right one very much 

 higher than the left. Proceeding downwards and backwards to the posterior 

 inferior angle is a well-marked angular fold, below which the valve is evenly 

 convex, the right being the more so ; above the fold the shell is compressed and 

 hollowed on each side of the hinge-line. 



Interior.— The details of the interior have not at present been observed in 

 British specimens. 



Exterior. — The surface is ornamented with regular, eccentric, sub-imbricating 



18 



