150 On the Claws and Sjmrs of Birds 3 Wings. 
sponding structure is met with in them ; but Dr. Shufeldt 
was unable to find it in the specimens which he examined, 
and if its non-existence is confirmed, another item will he 
added to the many differences which separate the Vultures of 
the Old World from the so-called Vultures of the New 
World. 
2. The Claw and Spurs of the Screamer (Chauna derbiana). 
The wing of a Screamer (Chauna derbiana ) lately sent to 
me by a correspondent in Venezuela has supplied a very 
interesting specimen, as it affords an example of a well- 
developed claw and two spur's coexisting in the same species. 
Fig. 2. 
Outer surface of end of left wing of Screamer (Chauna derbiana), reduced 
-§, showing* two metacarpal spurs (Sp, Sp. 1) and claw on the first 
digit (Cl). D.l, first digit: Ph. 1, first phalanx; Ph.2, second 
phalanx. D. 2, second digit: Ph. V , first phalanx ; Ph. 2', second 
phalanx ; Ph. S', third phalanx. D. 3, third digit. 
The wing-spurs in the Screamer are well known to be of 
enormous size, and are no doubt formidable weapons of 
offence. They are placed one on the proximal and the other at 
the distal extremity of the coalesced metacarpals, and project 
nearly in a straight line away from the radial edge. The first 
spur, which rises from the base of the metacarpal, on the prox- 
