Prof. F. M'Coy on some new Mountain Limestone Fossils. 173 



anterior end large^ obtusely rounded, dorsal and ventral mar- 

 gin with a slight upward curvature, no byssal furrow ; poste- 

 rior end slightly narrowed, subtruncate, rounded ; beaks large, 

 obtuse, a broad ovate striated lunette beneath them on the 

 anterior side ; posterior lunette, the largest of the hinge-hne, 

 wide, hollow, bounded by the obtuse ridges of the dorsal mar- 

 gins; valves very convex in front, their depth beneath the 

 beaks five-sixths of the width from them to the ventral margin, 

 gradually becoming more compressed towards the posterior 

 end, where the depth is only half the width ; posterior slope 

 gently convex, undefined, diagonal ridge not marked ; surface 

 covered with thick, rugged, subequal ridges, arising a little 

 behind the anterior lunette, and slightly thickening towards 

 the posterior slope, which is defined by their termination, and 

 only marked by fine strise of growth parallel with the end ; 

 anterior lunette and a small portion of the anterior extremity 

 also nearly smooth ; the ridges, where the outer surfaqe is pre- 

 served, are covered with a minute irregular striation approxi- 

 mately parallel with the margin. Length from anterior to 

 posterior end about 5 inches 2 lines, width from beak to oppo- 

 site ventral margin 1 inch 11 lines, depth of both valves 1 inch 

 9 or 10 lines. 



This fine species is remarkable for the clavate form produced 

 by the gibbosity of the valves near the anterior end and the 

 tapering towards the posterior extremity. Of the internal im- 

 pressions I have only seen the anterior adductor, which is broad, 

 rounded, and shallow. The only approximation to this species 

 published that I know is an imperfect fragment of one end of a 

 shell called S. maxima by Portlock, Geol. Rep. t. 36. f. 1, which 

 is flatter with smaller beaks, a more truncate anterior end, &c. 



Not uncommon in the carboniferous limestone near Llangollen, 

 North Wales. 



{Col. University of Cambridge.) 



Sanguinolites subcarinatus (M'Coy). 



Sp. Char. Elongate oblong, tumid; beaks very large, obtuse, 

 near the small, rounded, anterior end, in which there is an 

 abruptly hollowed space beneath the beaks; posterior end 

 narrow, square, truncated; diagonal ridge angular, slightly 

 sigmoid, strongly defined fi-om the beak to the respiratory 

 angle ; posterior slope smooth, slightly concave ; sides slightly 

 flattened, with coarse irregular striae and irregularities of 

 growth parallel with the margin; ventral margin nearly 

 straight ; hinge-line as long as the shell, its inflected margins 

 broad, slightly concave, nearly at right angles to the plane of 



