252 Prof. T. R. Jones and Mr. J. W. Kirkby on the 



lithgowshire ; Carlops Quariy, Whitefield Old Quarry, in 

 Peebleshire ; Sunnybank Quarry, Abden, Gleniston Quarry, 

 Charlestown, Wilkieson, in Fife. 



4. BiftJiocyj)ris (?) pi/rula, sp. nov. 

 (PI. VI. figs. 10 a, lOh, 10 c, 11.) 



B. (?) pyrula is a rare form, though apparently of more 

 recent occurrence in the southern than in the northern portion 

 of the British area. 



It is subtriangular or sublunate in outline, highest behind ; 

 the dorsal border is arched, the ventral incurved, with a 

 rounded or subangular posterior extremity, and an obtusely 

 pointed anterior. The valves are convex and smooth ; the 

 lateral contour is acute-ovate with the greatest width near the 

 centre. Length ^V inch. Discovered by the late Mr. Charles 

 Moore, F.G.S. 



Localities. In Carboniferous Limestone at Backwell, Hol- 

 well*, and Weston-super-Mare, Somerset; Arnside, West- 

 moreland. 



5. BytTiocypris (?) Moorei^ sp. nov. 

 (PI. VL figs. 12 a, 12 J, 12 c.) 



It is questionable if we have seen this species in a thoroughly 

 perfect condition. The only specimens examined by us are 

 from the Carboniferous Limestone of Weston-super-Mare, 

 and sent to us by the late Mr. C. Moore. 



It is comparatively large, being -^ inch or more in length ; 

 has a long, flatly-convex, dorsal border ; a shorter ventral 

 border ; one extremity much higher than the other and boldly 

 curved ventrally ; and the small extremity evenly rounded. 

 The valves are rather compressed, and their contour, as seen 

 from above, is almost lanceolate, widest at anterior (?) third. 



G. BytJwcypris (?) thraso^ J. & K. 

 (PI. VI. figs. 13 «, 13 b.) 



Cythere thraso, Jones, MS. 1867, Quart, Journ. Geol. Soc. vol. xxiii. 

 p. 494. 



Suborbicular, rather longer than high ; dorsal and extreme 

 borders rounded, ventral flattened ; valves very convex, one 

 larger than the other and slightly overlapping it ; lateral 

 contour oval ; surface smooth. Length 3^5 inch. Discovered 

 by the late Mr. C. Moore. 



A rare species, and only as yet found in the Carboniferous 



* Quart. Jouni. Geol. Soc. vol. xxiii. p. 483. 



