250 Prof. T. E. Jones and Mr. J. W. Kirkby on the 



lists would take up too much space in tlie present brief ac- 

 count. 



1. Bythocypris Fhilli'p&iana^ Jones & HoU, var. carhonica^ 

 nov. (PI. VI. figs. 1 a, 1 1, 2 a, 2 7>.) 



Bairdia Phillipsiana, J. & H., Ann. k Mag. Nat. Hist. ser. 4, vol. iii. 

 p. 213, pi. xiv. fig. 7. 



Subovate or bean-shaped, convex ; dorsal border arched, 

 ventral border straight, extremities rounded, the anterior being 

 smallest ; the left valve overlaps the right all round ; lateral 

 contour ovate, widest behind, pointed in front j surface 

 smooth or minutely punctate. Length 4V to yV inch. 



This little Ostracod has much the form of the common 

 Coal-measure Cyprid (?) Carhonia fahulina, J. & K., with 

 which it has sometimes been confounded. It is, however, 

 smaller than the latter, has the left valve (instead of the right) 

 the largest, with a more decided overlap, and it is always 

 found in the marine beds of the Carboniferous-Limestone 

 series with Corals, Crinoids, Brachiopods, &c., and never in 

 estuarine beds with plants and fish-remains as the Carbonia 

 occurs. Discovered by Mr. John Young, F.G.S., of Glasgow. 



B. Fliillijpsiana (formerly Bairdia) is a Silurian species 

 differing but little from this form, which we place with it as a 

 variety. Bythocyjjris hilohata (Miinster) {Oythere^ Ann. & 

 Mag. Nat. Hist. ser. 3, vol. xv. p. 409, pi. xx. fig. 10) is a 

 Carboniferous relative, also of similar form, though nearly 

 twice the size. 



Localities. Arnside, in Westmoreland ; Woodend Quarry 

 and Dun Quarry, near Lowick, Northumberland ; Barmullock 

 Old Quarry, Hillhead Quarry, near Wilsontown, County 

 Boundary, Lanarkshire. 



2. Bythocypris (?) cuneola, Jones & Kirkby. 

 (PI. VI. figs. 3 a, 3 h, 3 c, 4 a, 4 h, 5, 6, 7 a, 7 b.) 



Cythere* cuneola, J. & K., MS. 1867, Trans. Geol. Soc. Glasgow, 

 vol. ii. p. 223. 



Elongate or suboblong, convex, with greatest height and 

 width rather behind the centre ; dorsal border flatly convex, 

 ventral border straight, extremities rounded ; left valve 



* The difficulty of allocating fossil Ostracodous valves to tlieir true 

 genera has been often noticed. Cythere was formerly the recipient of 

 nearly all doubtful forms, and is still conveniently used. Judging, how- 

 ever, by the relative size of the right and left valves (where possible), in 

 combination with their shape, we can refer to some recent genera as 

 representing certain old and even Palfeozoic Ostracods, with more or less 

 certainty. 



