CARBONIFEROUS FOSSILS OF IRELAND. 55 



PULLASTRA OVALIS. M'Coif. (PL VIII. fig. 20). 



Sp. Ch. — Transversely oblong, convex, twice as wide as long; ventral and dorsal margins parallel; beaks 

 small, close to tlic anterior end ; anterior end very short, rounded ; posterior end subtnuicate ; surface with 

 numerous, rather distant, sharp, concentric striae. 



This fine species partakes of the general similarity of habit of all the other Pullastra; it is, however, easily 

 distinguishable from all the Palreozoic species by its great size and peculiar outline : the concentric striae are 

 sharp, fine, and placed rather distant from each other, so as to form numerous, regular, flat spaces between 

 them (these spaces are usually elevated in the recent species, but the delicate intermediate striaj are usually 

 elevated in the fossil ones) ; the posterior end is slightly truncated ; the beaks tumid, but not very prominent ; 

 anterior side very short. Length one inch two lines, width tv^o inches four lines. 



Pullastra paeallela. Phil. sp. 



Venus parallela. Phil. Geol. York. 



Sp. Ch. — Transversely ovate, flattened; beaks subcentral; dorsal and ventral margins nearly parallel; 

 anterior side narrow, rounded ; posterior subtruncate ; hmule large, deep ; surface with delicate, sharp, concen- 

 tric strice. 



This beautiful little shell appears to belong to the recent genus Pullastra, it is slightly quadrate in form, 

 the posterior end being subtruncate, the surface is beautifully striated. Length four fines, width six lines. 



AsTARTE gibbosa. M'Coy. (Pl. VIII. fig. 11). 



Sp. Ch. — Orbicular, length five-sixths of the width, gibbous, with regular concentric ridges ; posterior 

 side subtruncate, rounded ; anterior side small, rounded ; beak small, tumid. 



This handsome shell is nearly allied to the A. compressa of the Indian Oolite, but is much more convex ; 

 the beaks are small, but tumid, placed close to the anterior end ; the posterior margin is convex. Length one 

 inch two fines, width one inch four lines. 



AsTARTE QUADRATA. M'Coy. (PI. XL fig. 4). 



Sp. Ch. — Subquadrate, gibbous; shell tluck, marked with strong, concentric, slightly irreo^ular grooves, 

 and a few strong, distant wrinkles of growth ; anterior end small, rounded ; posterior end subtruncate, very 

 obtusely rounded ; beaks obtuse close to the anterior end. 



This shell has a thick and somewhat rugged appearance from the prominence of the few laro-e wrinkles of 

 growth (as distinguished from the transverse sulci), which does not exactly accord with the usual appearance 

 of the AstartcB ; the form too is more quadrate than is usual in that genus, which is, nevertheless, the most ap- 

 proximate group in which to place it. Length one inch one line, width one inch six lines. 



Cyprina Egertonl MCof/. (PI. X. fig. 9). 



Sp. Ch. — Orbicular, convex; shell very thick; edge obtuse; surface covered with close, rounded, concen- 

 tric ridcfcs. 



This shell is so closely aUied to some of the recent species, and to others found in the tertiary beds of Italy, 

 that, were it not for its geological locality, it would be difficult to distinguish it as a species ; from all fossils of the 

 Paleozoic rocks, it is distinguished at a glance. The general form is nearly orbicular, and marked concentrically 

 \vith close, cord-fike stria, as in most of the genus, these stria are slightly irregular in size. Lencj-th three 

 inches three fines, width three inches eight lines. 



