144 TRANSACTIONS OF THE. [MAR. 17, 
margin moderately arched, having a narrow indistinct fold. 
Glabella large. cy lindro- conical, flattened on the sides, descend- 
ing oradually at the front, and bordered by a distinct, but 
faintly impressed dorsal furrow. The glabella has two pairs of 
furrows, which are set well forward, the posterior pair oblique 
and arched backward, the anterior pair faint, at first transverse, 
then arching backward. Occipital ring broad, marked off from 
the glabella “by a faint, continuous furrow ; the ring is arched 
forward at the side, bears a slight, comma- ‘shaped elevation on 
each side, and carries as short, “acute spine at the back. The 
fixed cheek is subtriangular; within the eyelobe it is about half 
as wide as the olabella; the ocular fillet is well marked and is 
directed backwar d; cheek nearly flat, concave near the eyelobe, 
which is long and moderately arched. 
Sculpture. This consists of fine, closely set granulations, 
just visible to the unassisted eye. 
Size. Length of the head- shield 17 mm.; width between the 
dorsal sutures, at the front 20 mm.; at the eyelobes about 24 mm. 
Horizon and locality. Purplish gray sandstone of Assise 3, 
at Hanford Brook. Scarce. Collected by W. D. Matthew, 1892. 
This species ditfers so much from the two preceding that it is 
placed in this genus only provisionally, 
Among the described species of the Cambrian, Zacanthoides 
typicalis, Walcott, comes nearest this. As the posterior dorsal 
suture of our species is not known, a satisfactory comparison can- 
not be made; it certainly has not the peculiar sculpture found on 
the cheeks of that species, and the ridge on the side of the oc- 
cipital ring in our species, is not the round tubercle represented 
on Z. typicalis ; but the sculpture of radiating lines is invisible 
on the outer surface of the test in species which have it well 
marked on the inner surface. Possibly there is a genetic gon- 
nection. 
It seems desirable to quote here for the benefit of those who 
may not have access to earlier publications on the St. John 
Group faunas the description of the genus of trilobites which 
is most characteristic of the fauna of Band b. 
PROTOLENUS Matthew. 
Nat. Hist. Soc. of N. B. Bull., 10, p. 34. 
Trans. Roy. Soc. Can., vol. xi., pt. 1v., p. 100. 
Head shield semi-circular, moderately vaulted, outer part of 
the cheek movable, prolonged at the genal angle into a spine. 
Middle piece of the head more or less quadrate. Anterior 
margin wide, having a narrow distinct foldat the rim. Glabella 
