190 Prof. T. R. Jones on the 



with some variation in shape; PI. VII. figs. 1 and 5, much 

 alike in outline, but differing in lateral contour ; figs. 6 and 14, 

 Dearly agreeing in outline and differing very little in contour. 



1. Cyf/iere HoUu, sp. nov. (PL VI. fig?. 5 a, 

 5h, 5 c (var. a), figs. 6 a, 6 b, Q c (var. b).) 



Length. Heig-bt. Thickness. 



Proportions:|j,j|^g^ 40" 23 19 



Measurements in lOOOths of an inch : — 



Fig. 6 : 66 36 30 



Var. a. Large, convex, smooth, ovate-oblong, relatively 

 Jons:, thick and high in the posterior moiety and well-rounded 

 behind; sloping up in the antero- ventral region to the nar- 

 rower but neatly rounded front. Back straight along hinge- 

 line. Edge view acute and narrow-ovate. End view some- 

 what obovate, almost round. 



This is near Cytltere superba, Jones and Kirkby, from the 

 Lower Carboniferous strata of Scotland (Ann. & Mag. Nat. 

 Hist, for October 1886, p. 266, pi. ix. fig. 11); but it is 

 longer and narrower. 



Two specimens. Smith Coll. no. 8I2. Benthall Edge, 

 Ironbridge. 



Var. b (figs. 6, a, b, c). This is also suboblong and other- 

 wise like var. a ; but it is relatively shorter, thicker, and 

 higher behind, and less contracted in front. The anterior 

 extremity is symmetrically rounded. The left valve is larger 

 than the right (as in fig. 5), and overlaps to a small extent on 

 the ventral border. Edge view ovate, somewhat compressed. 

 This is still nearer to C. superba in shape than var. a ; but 

 still it is not identical with it. 



It Avas collected by the late Dr. II. B. IIoll, from the 

 Woolhope Limestone of the Malvern Tunnel ; and to him the 

 species is here dedicated, witli cordial appreciation of his high 

 worth as a geologist and palaeontologist. 



It is quite possible that these varieties, a and />, coukl each 

 claim specific standing ; on the other hand, it might be that 

 (7. superba should be a variety with them. For convenience, 

 however, and according to wliat we know of Palaeozoic Cy the- 

 ridte, I think it will be best to hold them in the arrangement 

 indicated above. 



(Four specimens.) Fig. 6, Collected by Dr. Holl in the 

 "VVoolhope Limestone, Malvern Tunnel. 



