1881.] - Zo0logy. 907 
So we must regard these spurs as nothing more than weapons 
possessed by a limited number of favored genera, given to them 
for a definite purpose, as hard as it is for us to conceive why some 
birds should wear them, to the exclusion of others—but claws, 
particularly as they occur in the Cathartida, have a very differ- 
ent significance,—they may mean a great deal more. They are 
to all intents and purposes, useless to their owners—and the prob- 
lem simply presents itself to us, as to how they came by them— 
when did they first appear, and how? what are they the rudi- 
mentary remains of ? and much more that may forever be purely 
conjectural ground for us, but certainly constituting a view of the 
Subject that lies beyond the scope of such an essay as this, to 
treat or enter into. 
_ _ the only authority that comes to my mind at present, who de- 
Scribes these affairs in any general way, is Professor Owen, and 
this writer dismisses the subject in the following manner : 
“The index digit in Struthio and the medius digit in Apteryx, 
Support each their claw. The claw or spur, when present in other 
irds, e.g. Syrian Blackbird (Merula dactyloptera ), spur-winged 
§00se (Anser gambensis), knob-winged dove (Didunculus), jacana 
(Parra jacana ), mound-bird(Megapodius), screamer (Palamedea), 
18 developed from the radial side of the metacarpus, or from the 
index digit. The screamer has two spurs, the homotypes of the 
metatarsal ones in Pavo bicalcaratus, The claw upon the index 
of Archeopteryx was curved and sharp; and the remains of the 
"nique example of this ancient fossil bird make it probable that 
the hand had a second free unguiculate digit, perhaps the homo- 
lodge of the pollex. Although the instances of these weapons, 
and the occasional use of the wings in birds not so armed, ¢. g. 
the swan, show them in the light of means of attack, the bones 
=e pectoral limb in birds are modified mainly for volant 
ction,”’ 
At the present writing there are two rather imperfect skeletons 
of Pseudogryphus californianus, and two mounted specimens, the 
latter being unquestionably “ birds of the year,” in the Smithso- 
‘Alan Institution. In the younger, or at any rate the smaller of 
these last, we find this claw present and very prominent, though 
it occurs in both birds. It can be immediately brought into view 
of the curved anterior surface, something over a centime- 
ut 1.3 centimeters), being grasped about its base by the 
enon integuments of the upper extremity. Its horny sheath — 
Ng removed, it leaves an osseous claw, such as we find in the 
ote i 
i 
Mis 
