1896. | NEW YORK ACADEMY OF SCIENCES. 223 
and back. Cephalic shield broadly-transversely elliptical, high 
and contracted behind, sloping from the glabella in all direc- 
tions. Marginal fold and furrow strongly marked. Dorsal fur- 
row deep. Glabella suborbicular, rounded in front and behind, 
bearing a small tubercle on the axial line, one-third from the 
front; the width of the glabella is more than a third of that of 
the shield, and its length nearly half. The thorax is unknown. 
The pygidium is semi-elliptical, with rounded anterior corners ; 
the width is nearly a quarter greater than the length. Both 
dorsal and marginal furrows are deeply impressed. The rachis 
is conical and is greatly elevated above the rest of the shield ; it 
is slightly constricted near the anterior end, and about one-third 
from the front bears a small tubercle. The lateral lobes of the 
pygidium are rounded in at the anterior end by the rapid curve 
of the marginal furrow; and at the posterior end are gradually 
narrowed and are separated at that end by a furrow which con- 
nects the dorsal and marginal furrows. The marginal fold is 
rather wide at the extremity of the pygidium, and is rounded 
at the anterior corners. 
This species is distinguished from A. tessella by the entire ab- 
sence of the anterior lobe of the glabella, and by the round and 
prominent posterior lobe, having a small tubercle in advance of 
the middle of the lobe. The pygidium has a shorter, higher 
and more conical rachis, and the tubercle on it is round, not 
elongated as in A. tessella. 
The head shield of A. parvifrons var. mammillata Brogg re- 
sembles that of this species, but is longer; the rachis also of 
the pygidium is more cylindrical and its tubercle further back 
in Broggers’ variety. 
Size.—Length, 6 mm.? width, 3 mm. 
Horizon and Locality.—In the fine dark shales of Div. 1 d', 
Porter’s Brook, St. Martin’s. First collected by Dr. L. W. 
Bailey. 5 
The following species are classed as Longifrontes, although, 
from the absence of axial furrows, the one which is here first 
described might seem to be not properly placed there; but the 
thin, flexible test, the large basal lobes and the attenuated and 
segmented rachis seem to point to this as the proper place for 
Agnostus obtusilobus, the largest species found in the St. John 
group. 
AGNOSTUS OBTUSILOBUS, pl. xvi., fig. 5. 
Agnostus obtusilobus. Trans. Roy. Soc. Can., vol. iii., pt. iv., 
Poeh2p ple vaio, 9. 
Amended Description.—Body elliptical oblong. Cephalic 
