CRUSTACEA. 
107 
Proetus canaliculatus. 
PLATE XX, FIGS. 10, 11; and PLATE XXIII, FIGS 10, 11. 
ProUus canaliculatus. Hall. Descr. New Species of Fossils, etc., p. 73. 1861. 
Proetus canaliculatus. Hall. Fifteenth Kept. N. Y. State Cab. Nat. Hist., ji. 101. 1862. 
ProUus canaliculatus. Hall. Illnstrations of Devonian Fossils, pi. xx, tigs. 10, 11. 1876. 
The original of this species is a fragment showing the intra-sutural portion 
of the CEPHALON, and more complete material has not been observed, with the 
exception of a few detached cheeks which may safely be regarded as belong¬ 
ing to this form. 
The species is characterized by its violin-shaped glabella (genus AEonia, Bur- 
meister), constricted at the anterior angle of the eye, and broadly rounded on 
the anterior extremity. Its length would be more than two-thirds the length 
of the cephalon, and its width apparently somewhat less than one-third that 
of the cephalon. 
The transverse furrows are indistinct upon the crust, but appear to consist 
of three pairs and the accessory pair. A cast of the lower surface would 
probably show a small anterior pair. The first pair visible is transverse, 
and the posterior pairs are inclined backward. All the glabellar lobes are 
faint. The occipital lobes are conspicuous; the occipital furrow narrow and 
deep; the occipital ring moderately broad and fiattened. The border is very 
broad and fiat, and is grooved along the anterior limbus by two furrows, the 
anterior of which is narrow and close upon the edge, the other is broad and is 
separated from the frontal margin of the glabella by a rounded ridge Upon 
the cheeks these grooves become shallower and reduced to two planes, the in¬ 
terior and broader one horizontal, the anterior narrower and beveling. At the 
genal angles the border is produced into moderately long and stout spines, 
which are ridged upon the surface and minutely incurved at the tip. 
The eyes and palpebral lobes are comparatively large, the orbital ridge ele¬ 
vated, the cheeks fiattened at their summit below this ridge, abruptly curving 
to the marginal and occipital furrows. 
The surface is smooth upon the border, finely granulose upon the glabella, 
and pustulose upon the fiattened summits of the cheeks. 
