New and Little Known American Paleozoic Ostracoda. 137 
Size: Length, 1.2 mm.; height, 0.84 mm. 
Species of this and the P. seminulum, Jones, type, I can not 
regard as really belonging to Primitia, but I am not yet prepared 
to suggest a more fitting disposal of them. 
Position and locality : Occurs in the dark Upper Trenton lime- 
stone at Perryville, Boyle County, Ky. 
APARCHITES OBLONGUS, DN. sp. 
Plate X, Figs. toa, b, ¢. 
Carapace oblong, tumid, inequivalved, of irregular shape, widest 
posteriorly. Dorsal edge straight or faintly concave, rounding at the 
extremities. Anterior end semi-circular ; the posterior most curved 
and prominent in the upper half, and much less curved and trending 
forward in the lower portion ; ventral edge produced in the poste- 
rior half, straightened from there on anteriorly. Edges of valves 
irregularly thickened, apparently not overlapping. Surface smooth, 
glossy, most convex in the posterior half, the point of greatest con- 
vexity in the left valve Leing above the center, while in the right 
itis below it. The right valve is also much the most tumid in the 
ventral region. 
Size: Length, 1.21 mm.; height, 0.8 mm.; greatest convexity, 
0.78 mm. 
The irregular, oblong shape of this species distinguishes it from 
all others known to belong to this genus. In A. whzteavesz, Jones, 
from the Lower Silurian of Manitoba, the edges are similarly 
thickened and fluted, but in other respects the two species are quite 
distinct, that one being almost sub-globular in shape. 
Position and locality: Cincinnati Group, upper beds, at Mid- 
dletown, Ohio. ‘The species seems to be rare. 
(Zo be continued. ) 
