1883. | the Devonian Rocks of Canada. ' 159 
lepis. The genera Asterolepis and Bothriolepis of Eichwald, 
it should be premised, were both based upon detached bony 
plates of fishes from the old red sandstone of Russia, in 1840, and 
the distinctions between them were founded on peculiarities in 
their surface ornamentation. In Asterolepis the sculpture of the 
exterior consists of numerous, minute, isolated, conical tubercles, 
with radiating striz around their bases and in the interstices be- 
tween them, while in Bothriolepis the markings of the same sur- 
face consist of shallow pits, perforated by vertical canals and en- 
circled by a more or less complete network of raised ridges. All 
the species of Pterichthys described and figured by Agassiz in 
his monograph of the fishes of the old red sandstone have the 
sculpture of Asterolepis (Eichwald), but the Canadian form which 
in every other respect is a true Pterichthys, has the pitted orna- 
mentation of Bothriolepis. Pander, however, in his memoir on 
the placoderms, has maintained that Bothriolepis and Pterichthys 
are both synonyms of Asterolepis, and the Scaumenac bay speci- 
mens certainly show that there is no essential difference between 
Pterichthys and Bothriolepis. Moreover it is exceedingly likely 
that the Canadian Pterichthys is specifically as well as generically 
identical with the Bothriolepis ornata of Eichwald, though the 
latter species has never been described nor figured with sufficient 
accuracy to be recognized with any degree of certainty. 
There are two other points of interest in connection with 
this species of Pterichthys. In the monograph of the fishes of 
the old red sandstone already referred to, Agassiz gives an ideal 
Tesforation of the genus, In this restoration the front margin of 
the head is represented as bearing a pair of divergent and slightly 
curved labial appendages or barbels, which the author in the text 
; claims to have seen in specimens of his P. /atus, but which he 
indicates in the diagram by dotted lines, as if in some doubt of 
their actual existence. These barbels are omitted altogether in 
Pander’s more recent restoration of the same genus, reduced 
figures of which are reproduced in several of the geological man- 
„uals of the day. Yet in one of the specimens collected by Mr. 
Foord the barbels are plainly visible and do not differ either in 
shape or position from those indicated in Agassiz’s diagram, ex- 
Cept that they are a little closer together at their bases or points 
Of attachment. The flattened conic al, dermal processes on the 
‘Upper side of the helmet, one on each side of the orbit, as repre- 
