402 Prof. T. R. Jones on the 



the species was described in 1869 ; only a few more are now 

 known. Eeferred to in Mr, Vine's list, Q. J. G. S. vol. xxxviii. 

 p. 48. 



One specimen : — Vine Coll. xviii. Bed no. 25*. Tick- 

 wood Beds. 

 Three f Smith Coll. no. 3. Dormins'ton. 



( 



tj' 



specimens : \ no. 8. E ail way-cutting near 



Much Wenlock. 



3. Thlipsura angulata^ sp. nov. 

 (PI. XII. figs. 9 a, 9 5.) 



Proportions :— L. 22. H. 13^. Th. 12|. 



Carapace ovate and convex, marked on the posterior moiety 

 by an oblique depression, furrowing the surface from the 

 antero-dorsal region to the posterior margin. Below the end 

 of the furrow the valve is slightly depressed longitudinally 

 towards the middle, leaving a slight angular elevation of the 

 surface pointing backwards. Edge view of carapace not sub- 

 oblong as in Thl. corpulentaj but ovate with sharp posterior 

 end. 



One specimen : — Vine Coll. xvi. Bed no. 46. Shales 

 over Wenlock Limestone. 



Proportions 



The specimens under notice are subovate and convex, and 

 some of them have much resemblance to Thl. tuherosa^ J. & 

 H., in their narrow-ovate outline, their subovate edge view, 

 and the somewhat analogous style of the oblique folds and 

 furrows on their posterior moiety ; but there is an absence of 

 the tubercle on the anterior half of the valve which charac- 

 terizes Thl. tiiherosa. In Thl. plicata (fig. 10) the front pit 

 present in Thl. tuherosa is wanting, though in its varieties 

 (tigs. 11, 12, 13) this small crescent-shaped sulcus is vaguely 

 represented by one or more variable roundish pits. 



Fig. 10 shows two oblique hollows, one close to the 

 postero-dorsal margin and another parallel with it, lower 

 down, and much broader, a convex fold-like elevation divid- 

 ing them. 



Fig. 11 shows the larger sulcus lying as in fig. 10, but 



