New and Little Known American Paleozoic Ostracoda. 131 
low water mark in the Ohio River, in the vicinity of Cincinnati, O. 
The larger form (fig. 1) appears to be restricted to this horizon, 
but specimens like fig. 2@ occur, rather rare, it is true, in the lime- 
stone three hundred feet higher. 
PRIMITIA PERMINIMA, DN. Sp. 
Plate Vil Fic. 7. 
A minute, short or broad-ovate Prvimitia, having the dorsal edge 
straight ; the anterior end more narrowly rounded than the poste- 
rior, the ventral edge rather strongly curved, and the sulcus repre- 
sented by a well-marked sub-central impression. 
size: Length, 0.34 mm ; height, 0.25 mm. 
This species is in the main very much like the preceding, with 
which it is also associated, but being always much smaller and 
shorter, is readily distinguished. It should also be compared with 
P. simplex, Jones. 
Position and locality: Occurs with P. centralis in the shales 
and shaly limestones of the Utica horizon at the mouth of the 
Licking River, Covington, Ky. 
PRIMITIA IMPRESSA, N. Sp. 
Flave X, Fig. 2a,.3b, 3c, 4a, 40 and 4c. 
A small, ovate species, rather tumid, with the dorsal and ven- 
tral margins nearly equally convex, and the ends equal, or the 
anterior slightly the widest. ‘The free margins usually with an 
indistinct flange. Sulcus situated centrally, or a little in front of 
the middle, unusually deep, extending from the dorsal edge nearly 
half the distance across the valve, terminating abruptly. Just 
behind the sulcus a more or less faint swelling. 
pize. Length, o.6 mm.; height, o. 36 mm. 
The valves of this species are more convex than those of P. fad- 
ulina, Jones and Holl, and P. humilis, Jones and Holl, to both of 
which it is closely related. Both of those species differ further in 
having the posterior end wider, and the point of greatest convexity 
further removed from the dorsal edge. There is no species known 
to me from American rocks resembling this sufficiently to make 
comparison necessary. 
