232 TRANSACTIONS OF THE [may 18, 
from the Abenacus Subzone of the St. John group. It will be 
seen that from the earliest stages described, this species can be 
separated from others, and before the rachis of the pygidium is 
segmented, the minute tubercle on the third somite distin- 
guishes the species from A, Nathorsti, which has this tubercle 
on the fourth somite; in the young of A. fallax it is on the 
third somite, as in A. /fissus, but becomes obsolete at a later stage 
in the former species. 
Both the above variety and the type of A. fissus have been 
found at Porter’s Brook, but only the variety at Chapel Arm. 
At Porter’s Brook the species is known only from the highest 
fossiliferous beds of Division 1 d; so perhaps did not come to 
America with the first migrants of the Abenacus Sub-fauna. 
AGNOSTUS PUNCTUOosUs, Angelin. Plate xvi., fig. 11. 
Agnostus punctuosus, Ang. Paleontolog. Scand., p. 8, tab vi., 
fig. 11. 
Agnostus punctuosus, Broegg. Om Paradox’skifr. v. Krekling, 
p- 67, tab. vi., fig. 12 a and b. 
Agnostus punctuosus, Tullb. Agnostus arterna., p. 17, tab. i., 
fig. 5 a to d. 
Angelin’s description of this species is very brief, the follow- 
ing is Tullberg’s: 
“Test of both shields granulated. Marginal fold narrow. 
Glabella bilobate. Anterior lobe narrower than the posterior, 
subtriangular, divided lengthwise by a fine line sometimes 
scarcely visible. Posterior lobe ornamented on each side in front 
of the middle by a depression, and between these depressions by 
an elevated point, furnished behind the middle of the basal lobes 
with higher tubercules resting on lateral depressions, rounded 
behind. Basal lobes elongate, triangular, divided into two 
tubercles by a lateral depression, uniting behind the glabella. 
Cheeks separated in front of the glabella, furnished with lateral 
furrows not deep, slightly undulate, and with small points. 
Thorax with two joints, rachis ornamented with contiguous 
lateral tubercules, pleuree divided into two tubercles by a trans- 
verse line. 
“Pygidium without spines. Rachis three-jointed ; anterior 
joint shorter and broader than the others ; middle joint higher 
than the others, hexagonal, keeled, adorned with an elevated 
point; posterior joint elongated, round-acuminate, sometimes 
bordered by straight lines so as to become quite pointed ; often 
furnished at the middle with a minute point, and below it lateral 
depressions. In the adult the lateral lobes connect behind the 
rachis, in the young state they are separated by a fine line; the 
