188 BRITISH CARBONIFEROUS BRACHIOPODA. 



the knowledge we possess relative to this shell, thought it might be, perhaps, different 

 from C. Hardrensis, but I am inclined to look upon it as a simple local variation or 

 smaller race of the last-named species. In the shales of Newton-on-the-More and 

 Derwick, as well as in those of Rahoran, in Ireland, we find another variety, with very 

 fine stria?, which Prof, de Koninck has identified as his Chonetes laguessiana (fig. 19 

 of my plate), 'Monographic du Genre Chonetes,' p. 191, pi. xx, fig. 6 ; but after a very 

 careful examination of many specimens, I could not bring myself to consider it speci- 

 fically distinct from C. Hardrensis. Several of Prof. M'Coy's so-termed species appear 

 to me to be variations or synonyms of the shell under description, but as palaeon- 

 tologists may perhaps object to the view I have taken, it will be preferable as well as 

 desirable to allude to them under separate heads. 



a. — Chonetes {Zejjtcena) gibberula, M f Coy. Synopsis of the Characters of the Carb. Foss. 

 of Ireland, pi. xx, fig. 11, 1843 (23 of my plate). 



" Semicircular, length two thirds the width, very gibbous in the middle ; ears acute, 

 flattened ; surface very finely and regularly striated longitudinally ; length one and a half 

 lines, width three lines. 



Loc. " Calcareous slate of Lisnapaste, Ireland." M'Coy. 



b. — Ckonefes (Leptmia) mbminima, M'Coy. British Pal. Fossils, p. 456. PI. hi, 

 fig. 31, 1855 (fig. 24 of my plate). 



" Rotundato-quadrate ; length three fourths or four fifths of the width ; receiving 

 (ventral) valve very gibbous in the middle ; greatest depth a little behind the middle ; 

 hinge-line as long as the shell is wide, forming flattened, ears, slightly acute from the 

 sigmoid outline of the sides, having three or four moderately long, slender spines on each 

 side of the beak, extending backwards, as usual, in the plane of the margin ; front margin 

 moderately convex. Surface uniformly covered with close, obtuse striae, once or twice 

 branched, but nearly uniform in size on all parts of the shell, and so fine that twelve at 

 the margin only occupy half a line when decorticated, the impressed lines between 

 the striae of the surface being coarsely punctured, and the beak slit by very deep 

 impressions of the mesial septum, extending half the length of the shell. Entering 

 (dorsal) valve nearly as concave as the receiving one is convex ; surface similar in both 

 valves, the striae being crossed by fine, close lines of growth. Average width one and a 

 half line, the depth seems about half the width. Very abundant in a piece of the black 

 upper Carboniferous limestone of Derbyshire." (M'Coy, p. 456.) 



Obs. These two so-termed species appear to me to be nothing more than young shells 

 of C. Hardrensis, and Prof, de Koninck has placed the first among the synonyms of 

 C. sulcata, which I am likewise inclined to look upon as a synonym of C, Hardrensis. I 



