270 Prof. T. R. Jones on the 
imitate P, Smithii (Ann. & Mag. Nat. Hist. U7. c. pl. iv. 
fig. 5) to some extent, but still being much more attenuate 
and subacute at the ends, although the median convexity is 
strong. 
Ill. Byrnocyrris, G. 8. Brady, 1880. 
(Ann. & Mag. Nat. Hist. March 1887, p. 184.) 
1. Bythocypris Hollit, Jones, var. oblonga, nov. 
(Ph. BOVE ties? Wa G5"cs) 
Proportions :—L. 25. H.14. Th. 13 
This is rather more oblong in side view than the published 
type * and also more compressed. 
B. Hollit has been found also in the Fréjel shale, Goth- 
land. 
2. Bythocypris caudalis, sp. nov. 
(Pl. XY. figs. 2 a, 6,.c, and 3 a, b,c.) 
Bies2 2 L923." E12 he ee 
Bigot toe. tid ase ooe 
In both the figured specimens the postero-dorsal region 
slopes more rapidly than in B. Holl and ends with a blunt 
projecting angle, with which the hinder ends of the valves, being, 
as it were, squeezed or pinched together, form a kind of caudal 
process. The antero-dorsal edge also slopes down with a 
lower curve than in B. Hollii, giving a subovate outline to 
the valves. 
Fig. 2 a, however, has a bolder and more uniform curve on 
its postero-dorsal slope than shown in fig. 3a, where the 
posterior constriction is more strongly marked; this latter 
variety, too, is shorter, higher in proportion to its length, and 
has a somewhat fuller ventral curve. In edge view (figs. 2 5 
and 3) and in end view (figs. 2.¢ and 3c) there is no specific 
difference. 
Proportions :— 
3. Bythocypris symmetrica, Jones, var. obesa, nov. 
(Pip eX, fies. 7 @;_0, ic.) 
Proportions:—L.17. H.9. Th. 9. 
This carapace is very much like that of B. symmetrica, 
var. 6 (Ann. & Mag. Nat. Hist. /. c. p. 186, pl. vii. fig. 4), 
* Op. cit. p. 184, pl. v. figs. 1 and 2, and pl. vi. figs. 3 and 4. 
