42 Messrs. Jones and Kirkby on Carboniferous Entomostraca. 
ford.” Synops. p. 165, pl. 23. fig. 6; Local. p. 100 (“ Car- 
boniferous slate and arenaceous limestone,” Local. p. 48). Grey 
limestone, with Spirifer, Crinoids, &c., and some obscure Ento- 
mostracan valves besides the Bairdia under notice. This is in 
good preservation. In 1859 one of us carefully examined the 
specimen, and, having cleared away some of the matrix, con- 
sidered the carapace to have been sufficiently well shown, and 
regarded it as being somewhat different from Bazrdia plebeia, 
Reuss, in exhibiting less convexity in the antero-ventral edge. 
Unfortunately this very convexity could even then have been 
found by greater boldness of manipulation; for a year after- 
wards, on again closely examining the specimen, it came out of 
the stone, quite perfect, showing a fully curved hatchet-edge, as 
in B. plebeia. 
After the many doubts expressed as to the identity of the 
Carboniferous B. curta and the Permian B. plebeia, we cannot 
now recognize (with Sir RK. Griffith’s specimen clearly before us) 
a real specific distinction; and B. curta stands as the oldest 
name. B. plebeia, however, may conveniently remain as a term 
of inferior grade for the very prevalent form with a rounded 
antero-dorsal angle (and hence less hatchet-shaped anterior ex- 
tremity, as depicted in Reuss’s figure of B. plebeia, Jahresbe- 
richt Wetterau. Gesell. 1854, p. 67, fig. 5, and in those given 
in the Transact. Tyneside Field-club, vol. iv. pl. 9. figs. 1, 2, 4, 
and woodcut 1, p. 145). 
4. “ Bairdia gracilis.’ Synops. p. 165, pl. 23. fig. 7. As 
we have not seen this specimen, and as it is not referred to in 
the List of Localities, we have nothing to add to Prof. M‘Coy’s 
brief description of it, except that it seems to be the same as 
B. subcylindrica, Minster, sp. (Annals N. H. ser. 3. vol. xv. 
p- 409, pl. 20. fig. 13). 
5. “ Cythere amygdalina.” Synops. p. 165, pl. 23. fig 8. 
We have not seen this specimen ; and, not being mentioned in 
the List of Localities, it has probably been mislaid. We have 
seen, however, a form corresponding to fig. 8 in the hand-spe- 
cimen described further on as No. 10. Prof. M‘Coy states that 
“ C’, amygdalina” is “ common.” 
6. “ Cythere arcuata. Yellow Sandstone ; Dromard, Drapers- 
town, co. Londonderry.” Synops. p. 165, pl. 28. fig. 9; Local. 
p- 48 (Arenaceous shale,’ Local. p. 100). A blackish mica- 
ceous shale, rather hard but fragile, containing Modiole (?), and 
abounding with small Entomostraca, Leperditia subrecta, L. Sco- 
toburdigalensis, Kirkbya annectens (sp.n.), and others, but nothing 
corresponding to the figure given of ‘ C. arcuata,’ which we 
are inclined to believe to have been a specimen of L. subrecta 
partially hidden by matrix on its dorsal region. Prof. M‘Coy 
