New and Little Known American Paleozoic Ostracoda. 107. 
Part I: 
DESCRIPTIONS OF LOWER SILURIAN SPECIES. 
ENTOMIS MADISONENSIS, N. sp. 
fade Vil, Figs. 12 a, 120; 
Valves oblong-ovate, the back straight but short, the ends sub- 
equal and curved almost uniformly into the much more gently 
convex ventral edge. Sulcus deep, nearly central, extending from 
the dorsal edge fully two-thirds across the valve, bending forward 
a little at its lower extremity. Anterior half of valve moderately 
convex; posterior half more so, and rising- abruptly from the sul- 
cus. Surface smooth. 
Sigeqeeneth, 123 mm. ; height, o.78 mm. 
This, and a much larger form from the Niagara of Indiana, are 
the only species of Ztomis at present known to me from Ameri- 
can rocks. Though apparently a true species of the genus, 4. madz- 
sonensts does not seem to be very closely related to any of the 
European forms.* 
The strong sulcus will distinguish it from species of Primitia. 
Position and locality: Rare in the uppermost beds of the Cin- 
cinnati Group, near Madison, Ind. It is associated with Leper- 
aitia cecigena, S. A. Miller, and Aurychilina striato-marginata, S. 
A. Miller. 
PONTOCYPRIS (?) ILLINOISENSIS, nN. sp. 
Plate X, Tes. 16 a, 0, ¢. 
Valves depressed triangular, with the angles rounded. Extrem- 
ities subequal, but the anterior a little the widest. Ventral edge 
nearly straight, curving upward at the ends. Dorsal edge convex, 
most prominent a little in front of the center. Surface smooth, 
with point of greatest convexity a little in front of the middle, 
where a small spot differing in color from the remainder of the test 
is distinguishable. 
Size: Length, 1.0 mm.; height, o.5 mm. 

* The recently described LZztomzs rhombotdea, Jones (Quart. Jour. Geol. 
Soc., February, 1890), from the Hamilton Shales, of New York, seems to me 
to be quite different from true Zz¢omzs, and probably congeneric with certain 
forms from the Devonian of the Falls of the Ohio, for which I shall propose 
anew genus. 
