VINE : CARBONIFEROUS ENTOMOSTRACA, ETC. 
233 
4. Bairdia plebeia, Reuss. (PI. XII., Figs. 3, 5, 5a.) 
Bairdia plebeia, Reuss, 1854, Jahresbericht weltterau Gesellscb, 1854, 
p. 67, Fig. 5. 
Bairdia plebeia, Kirkby, Ann. Mag. Nat. Hist. Ser. 3, vol. II., p. 324, 
Figs. 1 & 7. 
Bairdia plebeia, Jones & Kirkby, Quart. Jour. Geol. Soc., Nov. 1879. 
In tbe last paper, several synonyms and special details are given. 
The Yorkshire specimens of this form differ somewhat from 
the variations of the type furnished by Jones & Kirkby, in their 
most recent paper of the genus Bairdia , from the Carboniferous rocks 
of Britain. One of the specimens, in the pointing of the pos- 
terior extremity, makes a very near approach to some of my Scotch 
and Northumberland specimens of B. submucronata J. & K., but I 
think that the whole of the specimens figured, may be placed under 
B. plebeia, Reuss. 
Formations : Permian and Carboniferous. 
Localities: Hurst, Richmond; Messrs. Jones & Kirkby give 
Weardale, Durham ; Wyebourne, Cumberland, and Settle, Yorkshire, 
as northern English localities ; and they say that B. plebeia appears 
to have been the prevailing form of the genus during the upper Palaeo- 
zoic periods.” A large number of other localities are given by 
authors, both in Scotland, and a few in Wales. It is not very 
common, so far as I can judge, in the North Yorkshire shales. 
5. Bairdia brevis, Jones & Kirkby (PI. XII., Figs. 4a, 4a.)? 
B. brevis , J. & K., 1867, Trans. Geo. Soc., Glasgow, vol. II., p. 221. 
B. brevis, J. & K., 1871, Armstrong & Young’s Cat. Garb. Foss, of West 
Scotland. 
B. brevis, J. & K., Quart. Jour. Geo , Soc., November 1879, p. 575, pi. XXXI., 
Fig. 1 & 8. 
In the last of these three papers, the authors’ describe and 
figure, with its several variations, this delicate little species, “ which, 
compared with its height, is the shortest species of the genus,” 
known to them. 
Localities : Hurst. The other English localities given by the 
authors, are Wyebourne, Cumberland ; Weardale, Durham ; Charter- 
house, Somerset ; and Scremerston, near Berwick-on-Tweed. 
Family II. — CYTHERLDiE. 
Genus cythere, Muller. 
“ Carapace closed, resembling a diminutive peach stone ; valves 
