14 ' CRETACEOUS ENTOMOSTRACA. 



One of them (figs. 38 and 39) is suboblong, broadly rounded in front, obliquely 

 rounded behind, arched on the dorsal, and slightly incurved on the ventral edge. 

 The other (figs. 42 and 43) is rather smaller, not so high in front, and straighter 

 on the ventral edge than fig. 38. Both have the same moderate and uniform 

 convexity. The united valves would show a long, sharp-ended, oval edge view, 

 and an oval end view. 



The difference between the two valves may be varietal, or even only sexual ; 

 fig. 38 being probably the female, and fig. 42 the male individual. 



If these left valves are the largest, the genus Bythocypris takes them in. 



We propose to name this species after Mr. A. J. Jukes-Browne, F.G.S., of H.M. 

 Geological Survey, who has kindly supplied several interesting specimens, having 

 taken much trouble in securing the Microzoa of the different strata of the Creta- 

 ceous series which he has had to examine during his work in the Geological 

 Survey. 



Localities. — From the Chalk of Londonderry (Mr. J. Wright) ; and the Chalk- 

 rock of Dunstable (figs. 38, 39, 42, 43, Mr. A. J. Jukes-Browne). 



5. Bythocypeis ? RcEMEEiANA, sp. nov. Plate II, figs. 28 — 30. 



Length '6 ; height '325 ; thickness '25 mm. 



This is a small, subtriangular, left valve, with an almost symmetrically arched 

 back, straight ventral edge, and neatly rounded ends, of which the anterior is 

 rather higher than the other. Convexity of the surface slight, lessening forwards, 

 and rather less ventrally than towards the back; hence the edge view of the 

 united valves would be narrow-lanceolate, and the end view narrow-obovate. 



Altogether this little form reminds us of the somewhat Bairdia-like and larger 

 Bythocypris elongata, Brady (' Challenger Report,' p. 47, pi. vi, fig. 1), although it 

 is not so subtriangular above (dorsally), and not incurved below. It is from the 

 Chalk-rock of Dunstable, and is named after the late Fr. Adolph Romer, of Claus- 

 thal, who pursued with advantage the study of the fossil Ostracoda of Germany. 



Locality. — From the Chalk-rock of Dunstable. 



6. Bythocypris ? Iernioa (Jones). Plate III, figs. 31, 32. 



CxTnEUE Iebnica, Jones, MS. System. Lists, &c., Belfast Nat. Field Club, vol. i, 



Appendix iii, 1875, p. 81. 



Length '775; height "375; thickness '3 mm. 



Carapace almost symmetrically arcuate, with nearly equal and rounded ends ; 



