572 T. R. JONES AND J. W. KIRKBY ON 
Carboniferous Limestone (Lower): Darcy Quarry (Dalkeith) and 
Mount Lothian, in Edinburghshire; North Mine Quarry (Linlith- 
gowshire), Hairmyres (Kast Kilbride), Auchenbeg (Lesmahagow), in 
Lanarkshire ; Dockra (Beith), Craigie (Kilmarnock), in Ayrshire. 
Other figures of this species are here given for the purpose of 
showing the pitted surface that often characterizes well-preserved 
specimens. 
Fig. 17, Pl. XXXIL., is from Hairmyres, Kast Kilbride. 
From Blinkbonny Quarry and some other localities we have speci- 
mens, collected by the Geological Surveyors of Scotland, showing an 
irregularly reticulated surface, as depicted in fig. 18, Pl. XXXII. 
These specimens approach B. plebeia in some of its forms; but from 
that species they differ in having a decidedly convex ventral border, 
and much greater rotundity of valves, with greater relative length. 
5. BarRDIA GRANDIS, n. sp. Plate XXIX. figs. 1, 2. 
Cythere (Bairdia) plebeia, Reuss, var. grandis, Jones, 1859, Trans. 
Tyneside Field-Club, vol. iv. p. 162, pl. xi. fig. 13. 
From Whorlton and some other localities we have a large form of 
carapace-valve that well answers to the cast described and figured 
as B. plebeia, var. grandis, as above quoted. ‘The carapace reminds 
us rather more of B. subdeltoidea, as to its shape, than B. plebeva. 
Its size, too, and its relatively greater height and less produced 
posterior extremity, all distinguish it from B. plebeia. Hence we 
raise it to specific rank, and describe it thus :— 
Subdeltoid in outline; length less than twice the height. Dorsal 
border boldly convex, with sinuous anterior and posterior slopes ; 
ventral border straight. Anterior extremity broad, rounded ; pos- 
terior extremity bluntly pointed. Surface smooth. Length 
aL. inch. 
"3B, grandis has been found in Yoredale Rocks at Whorlton, Dur- 
ham, and in Carboniferous Limestone (Lower) at Carluke, Lanark- 
shire. 
6, Barrpia mucronata, Reuss. Plate XXIX. fig. 11. 
B. mucronata, Reuss, 1854, Jahresb. wetterau. Ges. p. 67, fig. 6. 
B. mucronata, 1855, Richter, Zeitschrift deutsch. geol. Ges. 
vol. vil. p. 531, pl. 26. figs. 18, 19, 
We have a single specimen of a carapace-valve from Whorlton, 
which corresponds closely with the figure of B. mucronata given by 
Reuss and Richter, except in being somewhat higher—a difference 
of, perhaps, no moment as to specific relationship. Reuss describes 
the species as follows :—‘ Elongately elliptical ; rounded in front ; 
running out behind into a long, narrow, compressed flap; upper 
margin arched; under margin almost straight; surface smooth.” 
This answers very well for our specimen. 
In Voredale Rocks at Whorlton, Durham. 
7. BAIRDIA SUBMUCRONATA, n. sp. Plate XXIX. figs. 12-18. 
B. mucronata, Reuss, var. submucronata, Jones and Kirkby, 1867, 
Trans. Geol, Soc. of Glasgow, yol. ii. p. 222. 
