ivy) 
ca) 
So 
PALEOZOIC PALEONTOLOGY. 
ARTHROPODA. 
TRILOBITA. 
LICHAS PUSTULOSUS Hall. 
Plate XL., Figs. 1-2. 
1859. Lichas pustulosus Hall, Pal. N. Y., vol. III., p. 366, pl. 77, 
figs. 9-12, pl. 78, figs. 1-7. 
Dscription.—“Pygidium somewhat triangular, excluding the mar- 
ginal extensions of the ribs. The axis is extremely prominent, occupy- 
ing about one-third the entire length, rising at its posterior extremity 
into a rounded boss, from the centre of which proceed two strong 
spines, with a smaller one on each side, and two in front and behind 
in the line of the two central ones. Median lobe below the axis promi- 
nent and rising in the middle into a strong node, bearing a double 
spine, and thence sloping abruptly backwards, and deeply bifurcate 
at the extremity. Ribs broad, extending in broad, mucronate pro- 
cesses beyond the sinuosities, which divide them for about one-third — 
of their entire length; the submedian groove extends to the ex- 
tremities, which are always gently bent upwards. The inner fold 
of the marginal limb is*extremely thickened and deeply striated.”— 
Hall. 
Remarks.—Two imperfect specimens of the pygidium of this species 
have been observed from the Becraft limestone. One of these has the 
test partly preserved and shows, in an exceedingly indefinite manner, 
the prominent axis and the broadly-ribbed plure, with some scattered 
spine bases upon the surface. It is broken along the entire margin, so 
that the spine-like extensions of the ribs are not preserved. The second 
specimen is an impression of the doublure of the posterior portion of 
the pygidium, and shows the two terminal, marginal spines and a 
single lateral one on one side, all the remaining portion of the indi- 
vidual having been destroyed. These terminal and lateral spines are 
somewhat more obtusely pointed than in any of the original illustra- 
tions of the species, but there can be no doubt as to the specific identity 
of the New Jersey specimens. 
