66 
PALEONTOLOGY OF NEW YORK. 
The pleura, are moderately broad and bear eleven or twelve low and flat 
annulations, which are grooved by fine impressed lines, and become obsolete 
upon the wide and slightly thickened border. 
Hypostoma. Elongate, sub-triangular; width on the anterior margin equal 
to the length. Antero-lateral angles broadly auriculate; lateral margins 
incurved and rapidly approximating. The posterior margin apparently bears 
five minute spines, one situated medially, and two on either side, but the only 
specimen observed is somewhat broken at this part, and its character cannot 
be satisfactorily determined. Margins thickened and sharply deflected. 
Centrum low, depressed-convex. Posterior sulcus conspicuous; postero¬ 
lateral pits moderately strong and elongate. 
Surface Ornamentation. The glabella is covered with moderately strong 
and evenly disposed tubercles which become obscure or obsolete upon the 
cheeks and margin. The frontal lobe of the glabella bears a circular pit on 
the axial line just back of its centre. The segments of the thorax appear 
faintly pustulose upon the axis; otherwise the surface is smooth or minutely 
granulose. 
Dimensions. The single entire individual known measures as follows. 
Length_ 
Body. 
. 80 mm. 
Cephalon. 
23 mm. 
Thorax. 
32 mm. 
Pyg-idium. 
25 mm. 
Hypostoma. 
18 mm. 
Width_ 
_ 44 mm. 
44 mm. 
41 mm. 
30 mm. 
18 mm. 
Observations. The pygidium of Dalmanites Calypso shows strong points of 
similarity with that of D. Erina. They differ, however, in these respects; (a) 
the type of D. Erina is faintly nodose along the axial line, hut not angulate or 
spinose, (b) the shield is more depressed, (c) the outline is a broader curve, and 
(d) the border wider and usually somewhat unsymmetrical. It may eventually 
become necessary, Avith a more complete knowledge of the latter species, to 
unite the two under one designation, but with our present material is seems 
desirable to retain the species tentatively as distinct. 
Distribution. Upper Helderberg group. Corniferous limestone; Sandusky, 
Ohio; Falls of the Ohio, Ky.; Schoharie, N. Y. 
