220 NEW YORK ZOOLOGICAL SOCIETY: 
DEVELOPMENT OF THE OSTRICH FEATHER. 
It is probable that early disuse of the wing as an organ of 
flight in the Cassowary, consequent on the restricted and forested 
condition of its habitat, led to a rapid reduction in the number of 
remiges. We now find only five or six stout, black, polished 
spines projecting from the edge of the wing. Exact homologies 
of these are to be found in the wing of the adult Apteryx. Here 
we find that the primaries possess a long, stout calamus, with the 
rhachis very distinct, but weakly developed. In the primary of 
a nestling Cassowary a correspondingly weak, scanty-vaned 
rhachis is formed, which ultimately breaks away at the umbilicus. 
Thus, in the adult Cassowary, the primaries are merely enlarged 
calami, which appear as hard, brittle spines. Their special use, if 
they have any, is yet to be discovered. The statement that they 
are of use in defense is absurd, both on account of their posi- 
tion and their weakness. The suggestion that they may aid 
the bird in extricating itself from a tangle of vines and 
undergrowth is very improbable, owing to the exceedingly weak 
musculature. 
The large size and unusual number of the remiges in the wings 
of the Ostrich and Rhea may have resulted from their secondary 
use as aids in swift running against the wind, a kind of half- 
return of the lifting function of the wings of their ancestors. 
The less reasonable alternative hypothesis is, that the line of 
descent of Struthio was through some long-armed, multi-remiged 
race, with albatross-like wings. The Emeu and Apteryx, like 
the Cassowary, apparently began their return to a terrestrial life 
upon islands, or in more or less forested regions, where wings 
