188 Prof. T. R. Jones on the 



This subtriangular or subreniform carapace has been already 

 sufficiently described in the Ann. & Mag. Nat. Hist, for 

 March 1869, from the Wenlock Limestone, near Malvern. 

 The present specimens, however, of the typical form (PI. V. 

 fig. 4) have rather thinner valves and therefore more delicate 

 outlines in profile and contour. We recognized it also in a 

 Scandinavian Limestone {Joe. cit.). 



PI. V. fig. 3 shows a larger and more ovate carapace, with 

 proportionally thinner valves (var. major). 



The Carboniferous variety of this species (var. carhonica, 

 J. & K., Ann. & Mag. Nat. Hist. ser. 5, vol. xviii. p. 250, 

 pi. vi. fig. 1) is very much like this predecessor, with but 

 slight modification of its features. 



Vine Coll. (two specimens). Fig. 3. No. Viil. Beds 

 no. 25 and 25*, Tickwood Beds. 



Smith CoU. (three). Fig. 4. No. 53. Railway-cutting, 

 side of Severn, L'onbrido;e. 



8. Bijtliociipris pustidosa, sp. nov. 

 (PI. VII. figs. 13 a, Vdb.) 



Length. Height. Thickness. 

 Proportions :— 20 11 13 



Measurements in lOOOths of an inch : — 



Left valve 35 18 



Right valve 31 15 



Thickness of carapace .... 17 



Carapace strong, convex, ovate-oblong, arched above, 

 straight below ; hinder end rounded ; front depressed, con- 

 tracted, and sloping, with an oblique curve. Left valve 

 overlapping all round. Lateral contour (edge view) acute- 

 ovate. Surface pimpled with (red) raised spots. 



Smith Coll. (one) no. 40. Stoke-Saye, near Craven Arms, 

 (three) no. 60. Railway-cutting, side of 

 Severn, Ironbridge. 



9. Bytliocypris ? seminulum, sp. nov. 

 (PI. VI. figs. 9 a, 9 b.) 



Proportions :— L. 9^ H. 5. Th. 4^. 



Carapace small, convex, subreniform, arched above, nearly 

 straight below ; ends nearly equal, but one rather more fully 

 curved than the other. Lateral convexity central and sym- 

 metrical (fig. 9 Z>), making an acute- oval outline. 



Smith Coll. (one) no. 53i. Railway-cutting, side of 

 Severn, Ironbridge. 



