CARBONICOLA OBTUSA. 61 



margin, and suggested that the TJnio tellinarius of Goldfuss and de Koninck, which 

 is also stated to possess this character, may belong to Sowerby's species. 



The only specimen showing the hinge-character of this species is in the Wood- 

 wardian, and I have been allowed to figure it and other specimens from that collection 

 by the kindness of Professor McKenny Hughes (PI. VI, fig. 44). In the drawing 

 the fragment is looked at from below, and shows the lower edge of the hinge-plate, 

 which is non-articular, the upper part of the plate being in consequence fore- 

 shortened. 



This fragment shows a total absence of any prominence which can be con- 

 structed into an anterior lateral tooth ; but there is a sloping surface continuous 

 above the striated lunule, which becomes thickened and raised, immediately 

 below the umbo, into an oblique posteriorly diverging cardinal tooth. Immediately 

 posterior to it is a pit, so that the tooth in the right valve is immediately in front 

 of that in the left valve ; the pit in the right valve has a plain triangular surface, 

 and there is no evidence of any posterior lateral tooth. 



M'Coy states (p. 515, op. supra cit.), " Casts show the thick cardinal tooth, and 

 slender, elongate, lamellar lateral teeth." I am unable to understand this state- 

 ment, as I cannot conceive it possible for the cast of a bivalve shell, the valves 

 being in their natural position, to show anything of the sort. The Professor 

 evidently mistook the groove left in casts on each side of the middle line by the 

 lower edge of the hinge-plate, both anteriorly and posteriorly, to represent ante- 

 rior and posterior lateral teeth. I have made a series of plaster casts of TJnio 

 tumidus, which have definite lateral lamellar teeth, but can obtain no indication 

 of them in the casts. 



This shell does not appear to have a very wide distribution. I only know of 

 the above-mentioned localities where it occurs ; and it appears to be confined to 

 the horizon of the Low Moor Ironstone beds. 



The large specimens, figured PL VII, figs. 11 and 15, belonging to Mr. George 

 Wild, of Bardsley, are from the Fullege Colliery, Burnley, and at about the horizon 

 of the Thin bed. 



7. Caebonicola obtusa, sp. nov. Plate VII, figs. 16 — 23; Plate XI, figs. 1, 2. 



Specific Characters. — Shape variable, but more or less subquadrate and flattened. 

 The anterior end is moderately convex, short but deep in a dorso-ventral direction ; 

 its border circularly rounded. The inferior border is rounded in front, 

 becoming almost straight posteriorly. The posterior part of the shell is narrowed 

 from above downwards by the slope of the upper border, which leaves a long, 

 bluntly rounded or truncate posterior border. 



