176 Jones AND Kirxksy—On Carboniferous Ostracoda from Ireland. 
Well preserved carapaces are common in the Cultra Shale. Some are more 
symmetrically rounded behind than others. 
This is a very abundant and wide-spread species in Lower Carboniferous 
strata in the east of Scotland (Roxburghshire and Fifeshire); and in some 
localities in Northumberland. Also in the deep-lying Carboniferous Shale of 
Northamptonshire, as proved by the Gayton Boring. 
3. Cytherella attenuata, Jones & Kirkby. 
1880. Leperditia attenuata, Jones & Kirxsy, MS. Quart. Journ. Geol. Soc., 
vol. xxxvi., pp. 568, 573, 588. 
1886. Cytherella attenuata, Jones & Kirxsy, Geol. Mag., dec. 3, vol. iii, p. 252, 
pl. vii., figs. 14a, 6,¢; Quart. Journ. Geol. Soc., 
vol. xlu., p. 510. 
Rare and badly-preserved single valves are present in the Carland shale. 
This species occurs in the Calciferous Sandstone of Fifeshire, and the Lower 
Carboniferous Shale of Gayton, Northamptonshire.* 
4, Cytherella incurvescens, sp. nov. 
(Plate x1., figs. 1-5.) 
In the Cultra Shale Cytherelle are relatively numerous, but not readily grouped 
as species. One series is new, and may be described as sub-oblong in shape, 
rounded almost equally at the ends, the anterior being usually the highest. 
The valves are more or less constricted ; the ventral margin always, and the dorsal 
in some cases, being incurved. The overlap of the left valve by the right is 
moderate. Edge view nearly lenticular in some cases, lanceolate in others; 
surface smooth. 
Taking the chief series of these Cultra specimens as very closely allied and 
* This and the preceding species (C. extuberata) ure present in great numbers in the lower beds of the 
Calciferous Sandstone series of Fife. Some of the cement-stones, and shales immediately overlying them, 
are full of their carapace-valves; now and then associated with other Ostracoda—species of Hirkbya 
and Beyrichiopsis—at other times apparently alone. For a few hundred feet of these beds these two 
Cytherelle (extuberata and attenuata) are decidedly the prevailing and most characteristic Ostracoda. 
Afterwards their place is taken by that other very common Lower Carboniferous form, Leperditia 
Scotoburdigalensis. 
When occurring as separate valves, more or less flattened by pressure (as they often are), they very 
much simulate Zeperditie in outline, and are easily mistaken for members of that genus. They were thus 
at first mistaken by us. Well-preserved carapaces, or good single valves showing the interior, however, 
undoubtedly prove them to belong to Cytherella. 
