256 Prof. T. R. Jones and Mv. J. W. Kirkbj oh the 



14. Leperditia ohesa, J. & K. (PI. VII. figs. 6 a, 6 h.) 

 Leperditia obesa, J. & K., MS. 1885, Geol. Mag. dec. 3, vol. ii. p. 540. 



Suborbicular ; valves evenly convex ; ventral border 

 boldly elliptical, posterior extremity flatly convex and i-atlier 

 liiglier than the anterior ; surface irregularly bestrewed with 

 comparatively large shallow pits, except near the free mar- 

 gins, where there is a narrow band without them ; a roundish 

 spot or area in the centre of the valve is also free from them ; 

 overlap moderate. Length -g^j to -^^ inch. 



This species is somewhat like L. suhorhiculata (Miinster) 

 and L. scotohurdigalensis (Hibbert) in outline, but differs 

 from them in its pitted surface. It is rare in the Carboni- 

 ferous Limestone at Arnside, Westmoreland. 



15. Leperditia compressa, J. & K. 

 (PL VII. figs. 7 a, 7 h.) 



Leperditia compressa, J. & K., MS. 1867, Trans. Geol. See, Glasgow, 

 vol. ii. p. 2iy. 



Nearly oval in outline, highest behind (in some) or in the 

 centre ; valves flattened in the central two thirds, then sloping 

 abruptly to the margins, which are rimmed ; dorsal border 

 short and straight, ventral border elliptical, extremities 

 rounded, the anterior more pointed than the other ; lateral 

 contour compressed-oval ; surface smooth. Length y^, incli. 



L. comyressa was discovered by Mr. John Young at Craig- 

 englen, Campsie, Stirlingshire ; it also occurs in the Yoredale 

 series, at Whorlton and Barnard Castle, in Durham ; and in 

 tlie Carboniferous Limestone near Bundoran, Co. Donegal, 

 Ireland. 



16. Leperditia lovicensis, sp. nov. 

 (PI. VII. figs. 8 a, 8 i.) 



Subtrigonal in outline ; valves swollen in centre, compressed 

 at extremities 5 anterior extremity subacute, posterior high 

 and rounded ; overlap of right valve slight ; surface finely 

 and densely punctate. Length -gV inch. 



Rare in shale above the Limestone (Yoredale), Woodend 

 Quarry, Lowick. The material was sent to us by Mr. James 

 Bennie. 



17. Leperditia acuta, J. & K. (PI. VII. fig. 9.) 



Leperditia Okeni (Miiuster), var. acuta, J. & K., 1865, Anu. & Mag. 

 Nat. Hist, ser. 3, vol. xv. p. 406, pi. xx. fig. 4. 



Subtrigonal, oblique ; anterior extremity acute and sloping 



