CRUSTACEA. 
219 
Turrilepas tener, n. sp. 
PLATE XXXVI, FIGS. 9-U. 
To this species are referred certain plates which have the same general out¬ 
line and surface features as in all the other specimens observed. One fragment 
of shale retains ten of these plates over the surface of a square inch. The out¬ 
line is equilaterally triangular and the surface nearly flat; the nucleus apical; 
the anterior and posterior margins straight, diverging at an angle of seventy-five 
degrees; the basal margin is gently sinuous, curving upward toward the poste¬ 
rior, and downward toward the anterior margin. Along the posterior margin, 
the plate is abruptly deflected toward the opposite side, but this is only for a 
very short distance. When the plates are not flattened there appears to be an 
elevated fold or broad ridge, situated in front of the axial line of the plate, 
running from the apex to the basal margin. The concentric striae are fine, ele¬ 
vated and crowded closely together, becoming obsolete just before reaching the 
anterior margin. As in other forms of this genus, these lines curve upward at 
or near the anterior and posterior margins. 
All the specimens observed have about the same length and height, which 
is 3.5 mm. 
Distribution. Hamilton group. In the lower shales at Centerfield, Ontario 
county, 
Turrilepas (?) Newberryi. 
PLATE XXXVI, FIGS. 16-19. 
Plumulites Newberryi, Whitfield. Annals New York Acad. Sciences, vol. ii, No. 8, ji. 217. 1882. 
Plumulites Newberryi, Whitfield. Pal. Ohio, vol. iii, pi. viii, fig-s. 6-11 (unpublished). 
The specimens referred to this species consist of detached plates, of large 
size, and generally obliquely sub-triangular outline. They are usually flattened 
in the shales and somewhat indistinctly preserved, but were evidently of sub- 
conical form. With a single exception, the nucleus is apical and inclined 
slightly to one side, the anterior margin gently incurved, the posterior convex, 
and the basal margin sinuous, a feature caused by a broad depression running 
from the apex obliquely backward. A single specimen preserved in a rolled con- 
