Paleozoic Bivalved Entomostraca. 305 
There are several examples of this common species, though 
they are not so abundant or so well developed as those from 
many British localities. Those figured are the most typical, 
others show some varietal differences. 
B, plebeia is perhaps the best known of the Carboniferous 
Bairdie, at least in Britain. It is also known from the 
Carboniferous strata of Russia. It was first found as a 
Permian species, and as such it is one of the most common 
Ostracods of the Magnesian Limestone of England and of 
the Zechstein of Germany. 
7. Bairdia brevis, Jones and Kirkby. 
CER XVI te2 22) 
Bairdia brevis, J. & K., Quart. Journ. Geol. Soc. vol. xxxv. p. 575, 
pl. xxxi. figs. 1-8. 
There are a few examples of this species, and they are not 
to be distinguished from those known to us from the Carbon- 
iferous-Limestone series of Scotland and England, where it is 
not an uncommon fossil. 
8. Bairdia amputata, Kirkby. (Pl. XVI. fig. 10.) 
Bairdia amputata, Wirkby, Transact. Tyneside Field-Club, vol. iv, 
1859, p. 155, pl. xi. fig. 22. 
This species 1s represented by five or six individuals, in all 
of which its subpentagonal outline is well marked. The 
specimens show the valves to have been coarsely pitted. 
L. amputata is found in the Carboniferous- Limestone series 
of Scotland and the north of England, and in the Permian 
rocks of Durham. 
9. Bairdia ampla, Reuss. (Pl. XVI. fig. 11.) 
Bairdia ampla, Reuss, Jahresb. Wetterau. Ges. 1854, p. 68, fig. 7; 
Jones and Kirkby, Quart. Journ. Geol. Soc. vol. xxxyv. 1879, p. 571, 
pl. xxviil. figs. 20-25, and pl. xxxii. figs. 17 and 18. 
Pig. 11 evidently represents 5. ampla, although the cara- 
pace is rather longer than in some examples of the species, 
not more so, however, than in others found in British Carbon- 
iferous strata. : 
B. amplais known as a British species in the Carboniferous- 
Limestone series, though it was first found in the Zechstein 
of Germany. We have also figured and described Carbon- 
iferous specimens of it from Russia *. 
* Ann, & Mag. Nat. Hist. ser. 4, vol. xv. 1875, p. 56, pl. vi. fig. 5. 
- 
