578 ON THE OSTRACODOUS GENUS BATRDIA. 
Fifeshire, in one of the thin limestones of the Calciferous Sandstone, 
about 3800 feet below the base of the Carboniferous-Limestone series. 
It was there associated with Beyrichia subarcuata and species of Spi- 
rorbis, Myalina, Macrocheilus(?), and Orthoceras. This, we believe, 
is the earliest appearance of Bairdie in Carboniferous strata. 
15. Barrpra crrcumcrsa, sp.n. Plate XXXII. figs. 13-16. 
Reniform, compressed ; length abouttwicethe height. Dorsal border 
arched ; extremities rounded, the anterior being the highest and most 
blunt; ventral border straight. Dorsal overlap of left valve strong. 
Lateral contour compressed in the centre, pointed at the ends; width 
rather over a fourth of the length. Surface smooth. Length ,, inch. 
The only example we have seen of this form is slightly injured 
near the anterior end, as shown in the figures. Its general outline 
resembles that of Cythere bilobata, Minster ; but that species is very 
convex, and has an incurved ventral margin. Buairdia equalis, 
D’Eichwald, seems to be a related form. 
From the Carboniferous Limestone (Lower) of Whitebaulks Quarry, 
near Linlithgow. The specimen belongs to the Geological Survey 
of Scotland. 
16. BareprA, sp.? Plate XXXII. figs. 7, 8. 
We have seen in the collection of the Geological Survey of 
Scotland the curious carapace from the Carboniferous Limestone 
(Lower) of Cowden’s Quarry, near Dunfermline, Fifeshire, that is 
represented by figs. 7 & 8, Pl. XXXII. It looks like a very much 
attenuated relative of B. precisa. It may probably be somewhat 
malformed ; for the postero-ventral region shows traces of injury. 
Until other examples turn up we forbear doing more than figure it. 
ConcLusion. 
The species of Bairdia we have described and figured in this 
paper are, it is believed, all that have been found in British Carbo- 
niferous rocks, with the exception of M‘Coy’s B. gracilis, about 
which little is known *. Two Bavarian species described by Count 
Minster (B. elongata and B. subcylindrica) have not yet occurred 
in Britain. Neither have four Russian forms described by D’Hich- 
wald?t, nor the Australian B. afjinis, Morris. Including these, 
there are twenty-three Carboniferous species belonging to the genus. 
Seven of these species are found recurrent in the overlying Per- 
mian formation ; but none of them are known to extend into Meso- 
zoic strata; and, excepting one doubtful instance ¢, none appear to 
be recurrent from the Devonian or Silurian rocks beneath. 
In the following Table we give a list of all the Palsozoic Bairdie 
known to us (omitting such as appear to be but varieties or syno- 
nyms), with references to figures of the species not noticed in this 
paper. The Table also shows the occurrence and recurrence of the 
species in the different subdivisions of the two upper systems of 
Paleozoic strata. 
* See Annals Nat. Hist. ser. 3, vol. xviii. p. 42 (1866). 
+ See also Ann. N. H. ser. 4, vol. xv. p. 52 (1875). 
{ D’Hichwald refers to B, curta as haying been found in the Old Red of Russia. 
