ADDITIONAL NOTES ON THE CAMBRIAN OF CAPE BRETON. 413 
species as figured by Linnarrsson in the wider frontal area of the cheeks 
and its convex front margin ; also in possessing three pairs of furrow’s, 
etc. From the Norwegian form, referred to this species by Bru'gger, 
it differs in its narrower glabella, rounded front, and in having three 
pairs of furrows, though the third one is faint ; the anterior area of 
the fixed cheek is wider, and is separated from the rest of that cheek 
by a shallow furrow ; it is, however, nearer this form than to any 
other known to me. 
Billings does not describe T. Fische?'i, except by contrast with 
other species (Upper Ordovician chieMy), but from his figure of that 
species, the Cape Breton form differs in the posterior marginal fold, 
which is not turned forward, like T. Fischeri. It also differs from that 
species in having an anterior buccal area and in the absence of pits on 
the front of the glabella.* 
I refer this species to Triarthrus rather than Parabolinella because 
of the narrow fixed cheeks, the long, backward-turned eyelobes and 
the regular, straight furrows on the glabella. 
Angelina ? sp. ? PI. XVIII, fig. 9. 
While we have no adult of this genus from the Tremadoc of Cape 
Breton, there is a young larval shield which seems to agree reasonably 
well with the characters of this genus by its suture and general out- 
line. Only the head-shield has been preserved. This is narrow, as are 
all its parts. The eyelobes are curved and linear, starting from near 
the front of the glabella in a heavy ocular fillet, the eyelobes are 
placed about the middle of the cheek. The movable cheeks have, 
extended spines, and are cut off in front by the curving suture. The 
glabella is ridged along the middle, and has traces of three pairs of 
faintly marked furrows. The occipital ring is narrow and weak. 
Sculpture.— The surface appears smooth. 
Size . — Length of this larval headshield, 5 mm. (or to the end of 
the spines 8 mm.) ; width, 7 mm. 
Asaphellus Homfrayi, var. PI. XVIII, figs. lOa-e. 
Salter’s description of this species is as follows ; 
Asaphus (Isotelus) long-oval, gently convex, having the head sub- 
angulate in front, and having short [genal] spines. Facial suture 
Palaeoz. Fossils, vol. i, p. 291, fig. 280. 
