re Rees Ge 
136 Cincinnati Society of Natural History. 
PRIMITIA RUDIS, Nn. sp. 
Plate X, Figs. 8a, 86 and 8c. 
Carapace oblong, subelliptical, the two extremities nearly equal 
and most convex in the lower half; dorsal edge slightly convex; 
ventral margin gently rounded, almost straight in the middle third, 
with an indistinct flange. Sulcus rather wide, well impressed, but 
more sharply defined on the anterior side than on the posterior, 
extending from the dorsal border obliquely forward to the center of 
the valve. In front of the sulcus and between it and the dorsal 
margin, a faintly defined tubercle or lobe. Posterior half the most 
convex, the slope to the edge from point of greatest convexity, 
somewhat flattened. An undefined depression in the postero-car- 
dinal region. 
Size:) Leneth) 1.0 anim: ssneleht, io) man. 
There is a rough and unshapely form and not a true species of 
Frimitia. Its affinities seem to he between P. cencinnatiensts, S. 
A. M., and Beyrichia (? Primitia) parallela, Ulr., in which case it 
would represent another link in the chain connecting Pvimitia' and 
Beyrichia. | 
Position and locality: Rare at Covington, Ky., where it was 
collected from the shales of the lower one hundred feet of the Cin- 
cinnati Group. 
PRIMITIA (?) SCULPTILIS, n. Sp. 
Plate VIIL, Fig. 6. 
Valves broad-oval or leperditoid in shape, the anterior end, 
though neatly rounded, much narrower than the posterior; in the 
latter half, from a point at about the center of the ventral edge to 
the subangular posterior extremity of the hinge line, the margin 
forms a semi-circular curve. In the anterior half the ventral bor- 
der is less convex and slopes upward. MHinge line straight, the 
length equaling two-thirds the length of the valve, with the extrem- 
ities obtusely angular. A depressed border, widest along the 
anterior and dorsal edges and very narrow at the ventral margin, 
encloses the elevated and coarsely pitted or sculptured main body 
of the valve. This is divided into two unequal lobes by a large 
sulcus, that is narrow and deepest above, but becomes shallow and 
much wider below the center. 

