182 Prof. T. R. Jones on the 



character is found in Gijtherella and Macrocypris. The 

 shape of this carapace does not correspond at all with that of 

 Ci/therella^ nor closelj with that of any known Macrocypris ; 

 but rather than make it the basis for a new genus, I have pro- 

 visionally grouped this specimen with Macrocypris, which has 

 the right valve larger than the left, thougli not so markedly 

 overlapping all round as in this instance. 



The carapace is of a narrow-subovate form with very thick 

 valves, the right strongly overlapping the left all round. It 

 has a considerable median convexity. Edge view compressed- 

 oval with subacute ends ; end view nearly round. At first 

 sight this little carapace looks like a dwarf Bythocypris PhiUip- 

 siana, but the overlapping valve is the right instead of the 

 left. 



Unique : collected by Dr. IT. B. HoU in ths; Wcnlock 

 Limestone, Crofts, near Malvern. 



II. PoNTOCYPRis, G. O. Sars, 1865. 



Pontocypris, G. S. Brady, Report Ostraeoda ' Challenger ' Expedition, 

 1880, p. 35. 



Several specimens in Mr. Vine's Collection have a some- 

 what Bairdia-Wko. carapace, but having one valve overlapping 

 the other on the dorsal border, and overla])ped on its own 

 ventral edge. This condition of the valves separates the form 

 under notice from Bairdia. Its peculiar subtriangular sliaps 

 presents a close analogy to that of Pontocypris ; and as the 

 recent forms, though with less overlap, do not gainsay a near 

 relationship, I provisionally refer it to this genus. 



1. Pontocypris Mawii, sp. no v. 

 (PI. IV. figs. 4a-4d, & fig. 7 ; fig. 6, var. yibhera, ? ?.) 



Length. 

 r Fig. 4 : 56 



Proportions:-? Fig. 7 : 32 



(Fig. 6 : (var.) 29 



Measurement in lOOOths of an inch : — 



Fig. 4 : L. 68. H. 35. Th. 33. 



Carapace convex, triangular-ovate or subpyriform ; arched 

 above, nearly straiglit below ; sharp, compressed, and tupcriug 

 at the ends ; posteriorly more attenuate, and with a longer 

 slope than in front, where it is almost truncate, curving with 

 a sudden slope downwards, and less compressed than behind. 

 I'hus the antero-dorsal slope is stee[)er and more convex than 

 the hinder slope, which is longer and flatter, and makes the 

 postero-ventral angle more jiroduced than the front. The 



