124 
PALEONTOLOGY OF NEW YORK. 
cops rana and Dalmanites Boothi, var. Calliteles, as does also P. Rnwi, in the basal 
layers of the Hamilton shales. 
The name Proetus marginalis, Conrad, as far as it has included the forms 
of Proetus occurring in the Tully limestone, may therefore be regarded as 
synonymous with P. Rowi, Green. 
Distribution. Hamilton group. In the Hamilton shales; On Seaver’s Creek, 
Township of Canandaigua, Ontario county; York, Livingston county; Ham¬ 
burgh and Eighteen-mile creek, Erie county; Vly creek and elsewhere, Otsego 
county. In the sandy shales of Schoharie county. In the Tully limestone; 
Below Lodi Landing, Seneca lake; at Weston’s quarry, near Spofford Corners, 
Split Rock, hear Borodino, and Tully, Onondaga county; Moravia, Cayuga 
county, and Cuyler, Cortland county. 
Proetus jejunus, n. sp. 
PLATE XXV, FIG. 7. 
Pygidium moderately large, the posterior outline being the arc of a circle. 
Axis elevated, relatively narrow, having one-fourth the width of the shield 
on the anterior margin; tapering rapidly to an obtuse apex distant from the 
posterior extremity. The apex is slightly elevated, a low, depressed ridge 
connecting it with the posterior border. Ten annulations can be counted, 
all of which show a retral bend over the axial line, and each bears a con¬ 
spicuous central node. 
The pleura are relatively broad and slope with a gentle curve outward to 
the narrow border. There are eight annulations, exclusive of the articulat¬ 
ing ring, and on the cast of the lower surface they appear to have been 
distinctly sulcate. Border smooth except near the antero-lateral angles, 
where it is encroached upon by the annulations. 
Dimensions. Length 13 mm., width 21 mm. 
Observations. This species is represented by a single pygidium from which 
the crust has been largely removed, but the specimen is sufficient to show that 
