
130 Cincinnati Society of Natural History. 
E. subequata is more elongate, has a well-defined mesial sulcus, 
and coarser surface granulations. . stviatomarginata, Miller sp., 
is not so tumid, has a mesial sulcus and no surface granulation. 
Position and locality: Birdseye limestone, High Bridge, Ky. 
EURYCHILINA STRIATOMARGINATA, 5. A. Miller. 
tate TX Las. 1A. 
Beyrichia striatomarginata, S. A. Miller, Cin’ti Quart. Jour. Sci., 
Volk alo, 23h er 4: 
Mr. Muiller’s figure of this species being unsatisfactory, another 
one is here offered. Mr. Miller states that he found his specimens 
‘in the upper fifty feet of the Cincinnati Group, ==) 7 eens 
three miles south of Osgood, Ind.’’ My specimens are associated 
with Leperditia cecigena, S. A. Miller, at the same horizon, several 
miles north of Madison, Ind. 
PRIMITIA CENTRALIS, N. Sp. 
Plate XG Fags. 1 and 20, 90eee 
Carapace sub-oblong, the dorsal edge straight, the ventral ellip- 
tically curved, the anterior end somewhat narrower and more 
sharply curved, both ends meeting the dorsal edge without forming 
distinct angles; free borders with a narrow flange, best developed 
along the posterior edge. Sulcus represented by a sub-central 
depression, not reaching the dorsal margin. Surface smooth. 
fe 0.6 mm.; height, 0.35 mm. 
Size :— ie oi 2 f 
0.75 O.AiOr ne 
This form is perhaps to be regarded as a variety of P. humilis, 
Jones and Holl, described from the Wenlock of England, but the _ ) 
slightly different outline, less abrupt posterior slope, more central | 
and less deeply impressed sulcus, and more defined flange in the 
Cincinnati form are distinctions deserving recognition. Fig. 1 
represents a larger variety in which the posterior half is consider- 
ably the widest, and the sulcus is situated nearer the dorsal mar- 
gin. It might be separated, but, as many intermediate phases 
occur, it has not been deemed advisable to do so. 
Position and locality: Not uncommon in the Utica shales near 

