Jones AND Kirkny—On Carboniferous Ostracoda from Ireland. 181 
1867. Leperditia Okeni, var. . Jones & Kirxsy, Trans. Geol. Soc. Glasgow, 
Scotoburdigalensis, vol. ii., pp. 216, 219. 
1872. 73 rr . J. Wricut, Ninth Ann. Rep. Belfast Nat. F. 
Club, p. 35. 
1880. se i; . Kirxsy, Quart. Journ. Geol. Soc., vol. xxxvi., 
p. 580. 
1884. n iN _ Jones & Kirxpy, Geol. Mag., dec. 3, vol. i, 
p- 357, pl. xii, figs. 1, 2. 
1884. Leperditia Scotoburdigal- Jonus, Proceed. Berwickshire Nat. Club, vol. x., 
ensis, No. 11, pp. 314, 321, pl. i, figs. 7 and 9. 
1886. * a . Jones & Kirxpy, Quart. Journ. Geol. Soc., 
vol. xlii., pp. 500, 503, and Table, p. 506. 
1886. * 5 . Jones & Kirxpy, Ann. Mag. Nat. Hist., ser. 5, 
vol. xviil., p. 254, pl. vii., figs. 4a, 6; 1886, 
Quart. Journ. Geol. Soc., vol. xlii., p. 510; 
1887, Proceed. Geol. Assoc., vol. ix., p. 504. 
Short-broad-oblong, straight above, more or less convex below; the ends 
fully rounded, rather unequal, one (posterior) having a slight postero-dorsal 
slope, giving some obliquity to that end; the anterior has a dorsal angle. 
Ocular spot and muscle-mark, one or both, sometimes apparent; hinge-line 
more or less than two-thirds of the length of the valve. 
L. Scotoburdigalensis, like some varieties of Z. Okeni and allied species, has lost 
more or less completely some or all of the real Leperditian characteristics—ocular 
spot and its escutcheon, muscle-mark and its radiate lines, traces of nuchal sulcus, 
and, to a great degree, the overlapping ventral edge of the larger valve. These 
featureless valves of degenerate species retain only the Leperditian outline, and 
even that is modified often by the want of strong dorsal angles; and they have 
thus come (by retrogression) to represent their probable progenitor, the far-away 
and early Aparchites of the Silurian seas. 
Examples of this well known Burdiehouse fossil are found among the other 
species from Cultra, but only rarely. It occurs also at Dromard. 
In Fife and other parts of Scotland (as well as at Burdiehouse) it occurs in 
swarms in some of the shales and limestones of the Lower Carboniferous series. 
This is a common form in some of the Lower Carboniferous strata in Scotland* 
and the North of England, as well as in Ireland. 
* The range of Carboniferous Ostracoda in Western Scotland is carefully tabulated by Dr. John Young, 
in the ‘‘ Transact. Geol. Soc. Glasgow,” vol. ix., part 2, 1898, pp. 310-312. 
TRANS. ROY. DUBL. SOC., N.S. VOL. VI., PART VII. 2F 
