Paleozoic Bivalved Entomostraca. an 
in the Carboniferous rocks of Scotland and freland; and may 
be regarded as L. Okent, var. INORNATA (M‘Coy). 
M. d’Eichwald’s figure of “Batrdia levigata” approximates 
to that of a Leperditia, and shows also the characteristic eye- 
spot. L. microphthalma, D’KHichw., also appears to be related 
to L. Okeni as a small variety. 
1**, Leperditia Okent, var. obliqua, nov. Pl. VI. fig. 3. 
With the typical Z. Okent from Phillineonowa we find a 
few specimens of a small Leperditia having a relatively short 
hinge-line, a long sloping posterior region, and a full ventral 
curve. Thisis near L. Okent, var. acuta (Ann. & Mag. N. H. 
ser. 3, vol. xv. p. 406, pl. 20. fig. 4) ; but it has a shorter hinge- 
line. In outline it approaches both L. Hisingert and L. Wil- 
liensis of Fr. Schmidt *, but agrees with neither. We propose 
to name this form var. OBLIQUA, as the greatest length is along 
a line much higher in front than behind. 
2. Beyrichia intermedia, Jones & Holl. Pl. VI. fig. 11. 
Length ;!; inch, height 51; inch. A minute, subovate, 
smooth Beyrichia, with a nearly semicircular ventral border 
and a deep subcentral sulcus, rather posteriorly placed; this 
sulcus cuts the valve vertically, and extends from the dorsal 
border to less than halfway across the valve; another, but 
faint, indentation exists near the smaller (anterior) extremity. 
In soft yellow limestone from near Likhwine, in the Govern- 
ment of Toula. 
This is undistinguishable from B. ¢ntermedia, J. & H.t, from 
the Upper Silurian rocks of Malvern, except that its shghtly 
greater length gives it a rather more oval outline. 
3. Primitia Hichwaldi,sp.n. Pl. VI. fig. 12, a, 6. 
_ Associated with the Leperditia of Phillineonowa we have 
found some specimens of an Entomostracan corresponding 
with the description of Primiiia given in the ‘Annals,’ ser. 3, 
1865, vol. xvi. p. 415, except that it has a reticulate and 
slightly wrinkled ornament. 
It is =, ich long, = inch high; has elongate, oblong, 
flatly convex valves, with a straight dorsal border, a vertical 
sulcus in the posterior half, narrow above and broad below, 
* “Ueber die russischen silurischen Leperditien,” Mém. Acad. Imp. 
Se. St.-Pétersb. ser. 7, vol. xxi. 1873. ; 
+ Ann. & Mag. N. H. ser. 4, 1869, vol. iii. p. 218, pl. 15. f. 7. 
