BULLETIN OF THE NATURAL HISTORY SOCIETY. 
4l>0 
from the posterior end indicates the termination of the rachis ; the 
sides lobes are sloped down to a somewhat flattened margin. On each 
side lobe there is a shallow groove near the front. 
The hypostome in this species is unknown, therefore the reference 
to Asaphellus is provisional. 
Sc^dpture . — The surface of the shell of this trilobite is smooth or 
minutely punctate. The underside of the movable cheek has a rugu- 
lose surface on the upper part, and a finely concentrically striated band 
on the slope outside of this ; the flattened band is covered with widely 
spaced anastomosing raised lines, parallel to the margin of the shield. 
The composition of the test in this species is different from that of 
A. llomfrayi which has a shining and polished surface as preserved in 
the shale ; this, on the contrary, had a dull surface, and appears to 
be more calcareous, as there is little but a film of the shell .substance 
left, where the containing shale has been exposed to weathering. 
Length, about 70 mm.; width, about 55 mm.; length of 
head shield about 26 mm.; of the thorax, 20 mm.; of the pygidium, 
about 24 mm. The pleune are about 45 mm, long, and the pygidium 
of about the same width. Scarce. 
A. (1) planus is distinguished from A. lloynfrayi, var. by its 
broader glabella, more prominent and more distant eyes, broader and 
less pointed front to the middle piece of the head shield, more obscure 
neck furrow, narrower thoracic rings, and the smooth and obscure axis 
of the pygidium. 
This form might be referred to Niobe, but for the obscurity of the 
glabella (and the almost entire absence of rachis to the pygidium, if w^e 
are right in referring the smooth pygidium to this head and thorax). 
This form cannot belong to Platypdtis^ Cal., becau.se it has eight 
segments, and no frontal enlargement of the glabella is traceable ; on 
the contrary, the glabella is conically rounded, as in Asaphus. 
This article is published with the permission of the Director of the Geological Survey, 
Dr. R. Bell. 
Issued, St. .John, N. B., January, 1902. 
