Paleozoic Bivalved Entomostraca. 303 
Carboniferous and Permian strata; it is now evident that 
they had a very wide geographical range. 
The specimens chiefly belong to species of Bairdia. They 
have evidently been obtained from a hard dark-coloured 
limestone. Nearly all of them are complete carapaces, not 
single valves. ‘The particulars sent to us as to locality are 
that they were found in the “ Carboniferous Limestone of the 
River Bardun, falling into the River Ezsin, South Mon- 
olta/?*. 
The following brief notes refer to the species and varieties 
determined by us. 
1. Leperditia Oxcent (Minster), and var. ‘nornata (M‘Coy). 
(Pl. XVI. figs. 1 and 2.) 
Leperditia Okent, Jones and Kirkby, 1865, Ann. & Mag. Nat. Hist. 
ser. 3, vol. xv. p. 406, pl. xx. figs. 1-3; and var. ¢nornata (M‘Coy), 
op. cit. vol. xvill. 1866, p. 44. 
Several examples of this species and its varieties occur in 
this set of Ostracoda. Fig. 1 represents a good example of 
the typical form. Fig. 2 is from a specimen that agrees 
closely with the variety tnornata (M‘Coy). There are 
other individuals belonging to a variety larger than either of 
these, being fully one ninth of an inch long and more oval in 
outline. ‘hese are similar to an unnamed form (hitherto 
grouped with the species) from Holwell, in Somerset, and 
other localities. 
L. Okent (with its varieties) is a common and widespread 
species in the Carboniferous- Limestone series. In these rocks 
it occurs in England, Scotland, and Ireland; and it has been 
found in strata more or less equivalent in Nova Scotia, 
Belgium, Germany, Russia t, and now in Mongolia. 
2. Bythocypris bilobata (Miinster). (Pl. XVI. fig. 3.) 
Cythere bilobata, Miinster, Jones and Kirkby, Ann. & Mag. Nat. Hist. 
ser. 3, vol. xv. 1865, p. 409, pl. xx. fig. 10. 
There are three examples of this species, all of which are 
similar, both im size and in other respects, to British specimens. 
This species occurs in the Carboniterous Limestone of 
Russia, Bohemia, Belgium, and England. 
* See also ‘ La Faune du Calcaire Carbonifére Inférieur du Bardoun 
en Mongolie,’ par P. Venukoff: 8vo, St. Petersburg, 1888, in Russian 
and French, pp. 211 and 226. 
+ See Ann, & Mag. Nat. Hist. ser. 4, vol. xv. 1875, p. 54. 
