Palu'ozoic Bicalved Entotnostraca. 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. 'JMiose tigured are the most typical, 

 others show some varietal ditFerences. 



B. plebeia is perliaps the best known of the Carboniferous 

 Bairdice, at least in Britain. It is also known from the 

 Carboniferous strata of Kussia. It was first found as a 

 Permian species, and as such it is one of the niost common 

 Ostraeods of the Magnesian Limestone of England and of 

 the Zechstein of Germany. 



7. Bairdia hrevis, Jones and Kirkby. 

 (PI. XYI. %. 9.) 



Bairdia brevis, J. & K., Quart. Jouru. Geol. Sue. vol. xxxv. p. 575, 

 pi. xxxi. tigs. 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. (PI. XVI. fig. 10.) 



Bairdia ampidata, Kirkbv, Transact. Tvneside Field-Club, vol. iv. 

 1859, p. 155, pi. xi. %. 22. 



This species is 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. 



B. amputaia 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. (PI. XVI. fig. IL) 



Bairdia ampla, Reuss, Jahresb. "Wetterau. Ges. 1854, p. 68, fig. 7; 

 Joues and Kirkbv, Quart. Journ. Geol, Soc. vol. xxxv. 1879, p. 571, 

 pi. xxviii. figs. 20-2-i, and pi. xxxii. figs. 17 and 18. 



Fig. 11 evidently represents B. 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. ampla is 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, pi. vi. fig. 6. 



