32 
PALEONTOLOGY OF NEW YORK. 
which attains its highest development in the Silurian. In outline and contour 
it shows an intimate relationship with an undescribed species of Dalmanites 
from the Lower Helderberg form.ation. It is, moreover, directly comparable 
with Dalmanites spinifera, Barrande, from the etage G, and D. rhenanus, Kayser, 
from the Wissenbach slates of the Lower Devonian. 
Distribution. Upper Helderberg group. Cayuga, Province of Ontario. 
Dalmanites (Hausmannia) Meeki. 
PLATE XI A, FIGS. 28-30. 
Dalmanites (imdet. sp.), Meek. Geol. Expl. Fortieth Parallel, vol. iv, p. 48, pi. i, figs. 11, lla. 1877. 
Dalmanites Meeki, Walcott. Monogi-. U. S. Geol. Surv., vol. viii: Pal. Eureka Dist., p. 207, pi. xvii, tigs. 
.5, 5a-b (not fig. Rc). 1884. 
The material representing this species consists of detached specimens of a 
glabella, a very large hypostoma and a quite perfect pygidium. The last- 
named part is very closely similar, probably identical with the pygidium of 
Dalmanites anchiops, but if the associated glabella belongs to the same species 
as the pygidium it will be necessary to regard these fragments as characteriz¬ 
ing a distinct specific form. 
Cephalon. The glabella is very similar to that of Dalmanites pleuroptyx, Conrad. 
The frontal lobe is large and transversely sub-elliptical, depressed-convex 
above ; the three pairs of lateral lobes are distinctly defined; the first two 
widest at their outer extremities, the last narrow, transverse and extending 
as an annulation across the glabella. The lateral furrows of the second pair 
appear to be nearly obsolete toward their distal extremities, causing a tend¬ 
ency to coalescence in the adjoining lobes. The occipital furrow is narrow 
and shallow, the occipital ring moderately broad and elevated, and without 
any central spine. 
Pygidium as in Dalmanites anchiops, although bearing two or three more pleural 
annulations than is usual in mature examples of that species. 
Hypostoma elongate-triangular, surface depressed-covex. Anterior margin 
slightly arched, antero-lateral extremities sub-auriculate. Centrum broadly 
