728 GEOLOGICAL SURVEY OF THE TERRITORIES 
characters; as, for instance, cranial peculiarities, or such forms as the 
sternum may assume. It seems to me that this latter bone would be 
particularly unreliable to adopt for any such purpose, for we will soon 
see in the Cathartide that its shape appears to vary with the age of — 
the individual, and a description of the bone in one bird, apparently 
an adult, would not answer for another of the same species, and per- 
haps of the same, or nearly the same, age. 
At the present writing it is well agreed among ornithologists, and, 
no doubt, very correctly so, that the Cathartide, or American: Vultures, 
form a family of themselves quite distinct from the vulturine Falconide 
of the Old World. This rather recent step, taken as it was through the 
aid of modern researches in the matter, will, in all probability, be a final 
one, and the Vultures of our continent will, we think, always be con- 
sidered as forming a well-defined family to which we can now hardly 
look for any new additions. The writer trusts that in the present 
paper he will be able to demonstrate to his readers, by the study of the 
skeletons of these birds, that the osteological characters of the group, 
some of which are new, go still further towards sustaining the division 
made and referred to above. The question as to how the Cathartide 
should be divided generically is quite another thing, and its discussion 
will be postponed until we have examined the various skeletons of the 
members of the family and compared our data with our present knowl- 
edge of the other systems of these birds’ economy. 
Vultures, as a rule, are found in the warmer climates, where they 
pursue their useful avocation as scavengers, feeding upon all carrion 
that chance may throw in their way. To carry on this mode of living 
we find certain marked features presenting themselves to us in their 
superficial anatomy or external topography that are common to all of 
them. The most important of these points we will hastily review here, 
so that the reader may have them at hand as external landmarks or 
references to compare, where comparison becomes possible, with points 
upon the skeleton within. In the first place, we find that their upper 
mandibles terminate anteriorly in a well-developed hook, which is much 
better defined when encased in its horny covering; in fact, it requires 
the addition of this integumental sheath to approximate the mandibu- 
lar margins in any of the Cathartidw. The head and a greater or less 
extent of the upper third of the neck is devoid of feathers, a fine down 
being found only in the young birds. There is no osseous septum na- 
rium present, and the external bony nasal apertures or nostrils are 
made to assume different degrees of perviousness by the surrounding 
cere. They have an external claw covered with horn, as in the ungual 
joints of the feet, that articulates by its base with the apex of the first 
digitin manus. A web is found between the inner and middle and mid- 
dle and outer toes occupying more or less of the basal thirds. Claws 
of the feet large, strong and curved, though these members are not 
fashioned for grasping purposes, as we believe Vultures never carry 
their plunder away by means of their feet, they being given these curved 
claws rather to hold down firmly the portion of the carcass upon which 
they may be feeding while they tear it in shreds by their powerful 
hooked beaks. It will be recognized at once that some of the charac- 
ters just enumerated have nothing whatever to do with the present 
mode of living of these birds, but may have done so in their ancient | 
ancestors; we refer particularly to the external claw exhibited on the 
manus, a character they possess in common with some, if not all, of the 
_ Old World Vultures. 
The family Cathartide, as defined by its most recent describers, con- 
= re 
