
New and Little Known American Paleozoic Ostracoda. 135 
tion is found in the typical form of the species near the ventral 
border just beneath the postero-dorsal node. 
In the slightly shorter variety, fig. 12a, the fourth elevation is 
missing, and the two dorsal knobs are less unequal in size. 
f Typical form: Length, 0.55 mm.; height, 0.34 mm, 
| The variety : ig O48 Ot Oe 2 20h: 
This species belongs to a group of species that ought perhaps to 
be distinguished generically from Primitia. All have two or more 
nodes, and are without a true sulcus. Of these species, P. mor- 
gani, Jones, is probably more closely related to P. nodosa than 
any of the others (7. bicornis, J., P. egualts, diversa, cornuta, J. 
and H., etc.), but differs like the rest in wanting the third and 
fourth nodes, and also in being without a distinct flange. 
Position and locality: The typical form occurs in the lower 
shales of the Cincinnati Group, in the vicinity of Cincinnati, O., 
from seventy-five to one hundred and fifty feet above low water 
mark in the Ohio River. ‘The variety is rare, and was found only 
at one locality near the tops of the hills north of the city. 
Size— 
PRIMITIA NITIDA, N. sp. : 
Fide VATE Fig. 7. 
Carapace leperditoid in shape, the posterior half being much the 
widest and most prominent in the lower portion, the hinge line 
straight and terminating abruptly at each end, the ventral edge 
oblique and most curved in the posterior half. A well developed 
flange surrounds the free margins. Sulcus very shallow, situated 
on the dorsal slope, but not reaching the margin. A similar but 
even more faint impression beneath it. Surface finely pitted, most 
convex in the posterior half, slightly flattened centrally, and slop- 
ing gently toward the anterior end. 
Size: Length, 1.05 mm.; height, 0.68 mm. 
The pitted surface and narrower anterior end distinguishes this 
species from P. centralis of this paper. The English Wenlock spe- 
cies P. valida, J. and H., also hasa pitted surface, but differs greatly 
in outline, the two extremities being almost equal. 
Position and locality: The specimens are contained in a dark 
fragment of limestone which was used for ballast by the Kentucky 
Central Railroad. As near as I can learn, the material was derived 
from Upper Trenton strata near Paris, Ky. 
