Jeffries.] 
304 
[December 21, 
In this case a claw would be of great interest since the second 
finger has usually two phalanges in the adult ; so that if the struc- 
ture seen by me was a claw — and it looked precisely like the 
undoubted claw on the first finger — we are obliged to acknowl- 
edge the presence in the young of a third phalanx and claw, which 
are entirely absent in the adult. Subsequent research revealed 
the presence of a very minute claw, or rather the rudiments of one, 
in two adult ducks, one a dusky duck (Anas obscura), the other a 
mallard (Anas boschas), both probably birds of the year. Regarded 
as aborted organs, these claws are of considerable interest, since 
they mark the end of the finger. The object of a claw is protec- 
tion of the tip of a digit and assistance in locomotion, hence 
claws are developed at the ends of the digits. Accordingly the 
ancestors of birds had a two-jointed first finger and a three- 
jointed second finger, both provided with claws. Thus the hand 
of birds agrees, so far as the phalanges are known, with that of 
reptiles and mammals. Whether the other fingers were like those 
of reptiles or mammals cannot be said, and for aught we know, no 
little finger was present. But at all events the number of phalanges 
in the first two fingers agrees with that of the first and second 
fingers, where five are present, and points to the first finger of 
birds being the first of the series. 
Below I give a tentative list of the number of the phalanges in 
the hand, and the presence of spurs and claws in different groups 
of birds. As there is scarcely a museum specimen in this vicinity 
which has the ungual phalanges preserved no reliance can be placed 
on them, so I have relied on the writings of Nitzsch, 1 Meckel, 2 Se- 
lenka, 3 Alix, 4 Morse, 5 and observations of my own. 6 The groups 
are given according to Sclater’s classfication as given in the Ibis 
for 1881, with the addition of the toothed birds according to 
Marsh, though there is little of the bird in the Archeopteryx 
besides the wings and feathers. 
1 Nitzsch. Osteograpkische Beitrage zur Naturgeschichte der Vogel. 
2 Meckel’s Vergleich. Anatomie. 
3 Selenka, Bronn’s Klassen und Ordnung des Thierreichs. Vogel. 
4 Alix. Essai sur l’Appareil locomoteur des Oiseaux. 
6 Morse. Anniversary Memoirs of the Boston Soc. of Nat. Hist. 
3 Jeffries, On the number of primaries in Birds, Bull. Nut. Ornith. Club, Vol. vi, p. 
156. 
