CARBONIFEROUS FOSSILS OF IRELAND. 65 



DOLABRA ANGUSTA. SoiC. SP. 

 CuculLxa angusta. Soio. Gcol. Trans — Cuculltca angusta. P//i/. Pal. Fos. 



Sp. C/i. — Square, length and breadth equal, very gibbous; beaks large, tumid, central; sides nearly 

 equal ; anterior side rounded ; posterior side truncated, straight, at right angles with the hino-c. 



DoLABRA COMPLANATA. SoiV. SP. 

 Cucullsa complanata. Soic. Geol. Trans Cuculla>a complanata. Pkil. Pal. Fos. 



The specimens of this species which have occurred, although numerous and easily identified, arc too im- 

 perfect for description. 



DOLABRA CORRUGATA. M'Coy. (PI. XI. fig. 12). 



Sp. CIi. — Transversely trigonal, gibbous, a broad, longitudinal, shallow depression in the middle of each 

 valve ; anterior end short, rounded ; posterior side lengthened, narrow, rounded ; surface smooth ; ridges 

 strongly wi'inkled concentrically; middle of the shell smooth. 



This species is easily known from its congeners by its trigonal form, and the few strong wrinkles which 

 mark the sides. Length one and a half lines, width two and a half lines. 



DOLABRA EQUILATERALIS. MCoy. (PI. XL fig. 14). 



Sp. Ch. — Square, length and width equal, equilateral, gibbous; beaks large, prominent, central ; posterior 

 ridge rounded ; posterior margin narrowed, slightly oblique ; surface smooth. 



In general form this shell bears a strong resemblance to some of the large casts of the L.lcBvifjatvm of the 

 Diirrhelm Keuper beds. The remoteness of their geological localities will, however, prevent the possibility of 

 their being confounded ; besides which, the present shell is almost perfectly equilateral, the other very inequila- 

 teral ; and the Keuper species has the posterior side very obliquely truncated, while it is very slightly so in the 

 present species ; it differs from the CucullcBa angusta, Sow., in its larger beaks, narrow posterior end, and more 

 depressed form ; and from the C. trapezium, in its shorter posterior side. Length one inch j(ive lines, width one 

 inch five and a half lines. 



DOLABRA GREGARIA. MCny. (PI. XI fig. 11). 



Sp. Ch. — Rhomboidal, gibbous; beaks prominent close to the anterior end; anterior side small, rounded, 

 angulated at the hinge ; posterior side dilated into a broad, flattened wing, obliquely subtruncate, rounded ; 

 body of the shell obliquely gibbous, divided in the middle by a broad, flattened depression, from the beak to the 

 front margin, bounded on each side by an obtusely rounded keel ; surface marked with a few irregular, trans- 

 verse striae. 



Length two lines, width two and a half lines. 



DoLABRA HaRDINGII. SoW. SP. 

 CucullEea Hardingii. Sow. Geol. Trans. — Cucullsea Hardingii. Phil. Pal. Fos. 



Sp. Ch. — Transversely oblong, very gibbous ; length two-thirds the width ; beaks large, tumid, close to the 

 anterior end ; anterior side very short, rounded ; posterior side slightly oblique, subtruncate ; a diagonal ridge 

 from the beak to the posterior angle, and one or two others on the posterior slojie ; surface with obscure, con- 

 centric lines of m-owth. 



None of the ridges on the posterior side are strongly marked. Length about one inch. 



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