SHUFELDT. ] OSTEOLOGY OF THE CATHARTIDA. 763 
of the shafts. We believe that this is the case in the vast majority 
of the Falconide, including the Old World Vultures. These unciform 
offshoots are very wide-spreading and prominent, more so among the 
American Vultures than in any of the Hawks or Eagles, and as a rule 
overlap the rib immediately behind them, but never two consecutive 
ones, as in some birds. 
There are some very interesting and distinctive differences between 
the ribs of the Cathartidw and these bones, as found among the Falcon- 
ide and the vulturine Raptores of the Continent; these differences are 
largely due to the form assumed by these very epipleural appendages, 
taken in connection with the greater breadth of the pleurapophysial 
bodies as already referred to, and shown to be characteristic of the 
family we are describing. 
We present afew outline, but accurate, sketches of these bones, chosen 
from several species, given in life size, as the best way to demonstrate 
these very striking and really diagnostic features. The first, marked 
m, is the rib from the anterior dorsal vertebra, taken from the left side 
of Pseudogryphus; n,0, and p are the ribs, from the same side, of the 
second dorsal vertebre of Catharista atrata, Neophron percnopterus, and 
Circus hudsonius, respectively. The feature which we desire to direct 
the reader’s attention to particularly is the descending process of this 
pleurapophysial appendage, here best seen in O. atrata (n), though it is 
no better marked in this Vulture than in others of the family to which 
it belongs. This peculiar form of the epipleurals of the ribs in the 
Cathartide is most decidedly marked among these bones chosen from the 
middle of the series, though it persists in a less degree in the first dorsal 
rib, as seen in m (Pseudogryphus), as well as in the appendage when it 
