CRUSTACEA. 
31 
of short spinules upon the lateral margins. These spinules are five in number 
upon each side, the first being the largest, their size diminishing posteriorly so 
that the last is little more than a crenulation of the margin. They are short, 
stout, acute, and directed backward. The terminal spine of the pygidium also 
is relatively longer and more slender than in the normal form. 
This specimen is from the decomposed chert of the Corniferous limestone at 
North Cayuga, Province'of Ontario. 
Dalmanites (Hausmannia) phacoptyx, n. sp. 
PLATE XI A, FIGS. 23-26. 
Fragments of three large pygidia show pleurae which are broad on the anterior 
margin, but narrow rapidly backward and are abruptly deflected toward the 
posterior extremity. The margin is entire and the border quite narrow, 
widening at the posterior extremity, where it is laterally flattened and pro¬ 
duced into a stout spine, having about one-fourth the length of the pygidium, 
and strongly bent upward. 
The axis is composed of eleven or twelve moderately broad annulations, 
and towards its posterior extremity merges into the caudal ridge and spine. 
The phur(B bear twelve or thirteen ribs which are separated by wide, shal¬ 
low sulci, and are strongly curved backward near their distal extremities. 
Each of these annulations is conspicuously sulcate. The surface is covered 
with spinules and acute tubercles which appear to be irregularly scattered 
over the annulations. On the axis they are sometimes in pairs or in single 
transverse rows, becoming crowded together near its margins; on the pleurse 
they appear to lie exclusively upon the anterior limb of each annulation, 
although the larger spinules are often so broad at the base as to extend across 
the entire width of the annulation. The surface between the tubercles and 
spinules is covered with fine granulations. 
Dimensions. The largest and most complete specimen observed has a length 
of 62 mm. to the tip of the caudal spine; its width across the anterior 
margin, when entire, would be about 85 mm. 
Observations. This species, though imperfectly known, is of interest as pre¬ 
senting a continuation into the Devonian formation, of a type of Dalmanites 
