FAUNA OF THE TRENTON GROUP. 
33 
a narrow central one winch does not expand rapidly forward, a pair of 
large anterior side lobes, and a small posterior pair. The posterior 
pair of glabellar furrows are deeply impressed, and joining the dorsal 
furrows, strongly isolate the anterior pair of lobes. Posterior lobes 
not strongly separated either from the central lobe, or the mounds 
hearing the palpebral lobes. Neck furrow deep, producing a distinct 
and narrow occipital segment. There is no pair of basal lobes back of 
the eye-mounds. 
Length of figured specimen, 5 mm., width between eyes V -b mm. 
This species is certainly very like the Russian form with which 
T)r. Clarke identified it. Hemiarges wesenbergensisj has, however, 
somewhat less isolated anterior side lobes, and snorter marginal spines 
on the pygidium, as Dr. Clarke has already pointed out. 
Giirich’s subgeneric name Hemiarges may well be adopted for this 
species, which lacks the basal lobes of a typical TrochuruSj though 
there is a suggestion of them in Schmidt’© figure of the Russian form. 
No trace of them is seen on American specimens, 
a 
Horizon and Locality. Mr. J. E. Narraway has found this species 
in the Crinoid beds in Hull, Que., and the figured specimen is from 
loose material at the Kirkfield liftlock, either from the DalmanelU 
beds or the Crinoid beds. In Minnesota, it has been found in the 
Prosser limestone at St. Paul and Wykoff. Weller found a species 
of the same genus, Hemiarges tuberculatus (Weller), in the Black 
River near Iliffs Pond, New Jersey. 
Genus, Encrinurus EmmricY 
Encrinurus cybeleformis sp. nov. 
Plate XI, figure 2. 
Known from pygidia only. Pygidium narrowly triangular in out- 
line, strongly convex, with long, narrow, axial lobe which is very low 
at the posterior end but is distinctly outlined. Pleural lobes curved 
sharply downward, and marked by nine pairs of rounded ribs, not 
ornamented with tubercles. Anterior end of axial lobe crossed by 
three sharp rings, and back of the third ring is a wide, smooth area 
along the median portion. At the sides of this area about fifteen or 
sixteen pairs of incomplete rings are interrupted by the smooth hand, 
and extend to within about 2 mm. of the posterior end, where the 
whole lobe becomes smooth. There is a median tubercle on the third 
ring, another where the sixth would have crossed, and faint traces of 
tubercles where the ninth and thirteenth should cross. 
Length of holotype, 8.5 mm., width at front, Y.5 mm. 
