742 GEOLOGICAL SURVEY OF THE TERRITORIES. 
upon the bone in many instances; they are less perceptible in S. gryphus 
than in any other member of the family. The remainder and unde- 
scribed half of each tomium running backwards is flat or slightly 
rounded, and includes on either side about the anterior fourth (C. aura) 
to the seventh of the maxillary (Pseudogryphus). Owing to the deep 
sides, the inferior aspect of the upper mandible is very much scooped 
out, and strongly reminds one of a well-shaped canoe; two sharp little 
ridges, one on either side, start from the tip of the beak here, and run 
backward as far as the palatine articulation, being nearly parallel with 
the tomial edges at the middle of their course. The maxillo-palatine 
fissure is wide and sub-elliptical in outline, terminating posteriorly by 
an opening in its are that leads into the true inter-palatine cleft. (Fig. 
120, Pl. XX.) 
In all of the Cathartide we find just within the lower border of each 
nostril a diminutive bony shelf, formed partly by the palatine, partly 
by the lateral processes of the intermaxillary ; following this along 
Catharies aura. 
towards the tip of the beak we find it to terminate in a conical socket 
on either side. In C. atrata they can be seen just within the anterior 
7 pen of each nostril, while in Pseudogryphus they are a full centimetre 
yeyond. 
_The bony nostrils in these birds are placed upon the sides of the supe- 
rior mandible and very nearly in their same planes. In form they 
assume more or less of an oval outline, being long and narrow in atrata, 
high and broad in the Californian Condor and the Turkey Buzzard. 
_ In Pseudogryphus and Sarcorhamphus, less so in Cathartes, their inferior 
and postericr margins blend with the transverse plate of the ethmo-tur- 
