SHUFELDT.] OSTEOLOGY OF THE CATHARTID&. 755 
from what follows that I consider the free ribs in this locality in the 
Cathartide, as well as the Falconide referred to, as cervical ribs. This 
may be my final opinion. 
Now, so gradual is the passage from the processes on the cervical 
vertebrae from which the ribs are formed to free ribs among the Vul- 
tures, that indeed, the first cervical rib has more the appearance of a 
bony plate than a rib, yet it freely articulates with its vertebra as the 
rest ot the dorsals do, and its presence makes the number of cervical 
ribs in C. atrata reckon three. Again, the vertebre possessing these 
free ribs are situated opposite the clavicles and other parts of the scap- 
ular arch, and form the “ root of the neck,” being so far removed from 
the dorsal region that we can only regard them as true cervical vertebra, 
The rudimentary manner in which these ribs are first exhibited on these 
vertebra is well shown in Plate X XT, fig. 114, cy, cy, for Cathartes aura, 
while in C. atrata, as we have remarked, the par-pleurapophysial plates 
are free as ribs in the vertebrae beyond these even. 
This arrangement reduces the number of dorsal vertebre in Sarco- 
rhamphus and Pseudogryphus to only three; that is to say, that in these 
genera we find three iree segments in the mid-column, where the pleura-. 
pophyses are connected with the sternum by the sternal ribs, while the 
vertebra immediately posterior to them is with these birds firmly anchy- 
losed with the ossa innominata. On the same page, then, we have just 
quoted from Owen’s Anatomy, it will not surprise us to find the statement 
in regard to the dorsal vertebre that “they have not been observed to be 
fewer than four (in some Vultures) nor more than nine throughout the 
class; the latter number obtains in Apteryx; the most common num- 
bers are six and seven.” Now, if we accept this, and also this anato- 
mist’s arrangement that the free ribs are dorsals and the vertebree 
bearing them dorsal vertebra, and there being ‘“‘ usual'y two of them,” 
then it would leave us a very limited number of vertebre between them 
and the sacrum that were connected with the sternum by sternal ribs 
(at the most two) in the Vulture referred to; so we are compelled to 
think, knowing as we do the usual condition of the ribs in these birds, 
that on this occasion the distinguished zodtomist himself reckoned his 
four vertebre as those that were articulated with the sternum by the 
intervention of sternal “ hemapophyses,” and for the moment did not 
note the free ribs. This would give the same formula as C. aura and 
others. 
With the exception of the vertebre that are grasped by the pelvic 
bones, these segments in all of the Cathartide are freely articulated 
with each other. This is likewise the case with Gypogeranus and Neo- 
phron percnopterus, and obtains also with our Circus hudsonius, in which 
species jive vertebre are allotted to the dorsal division of the column. 
Again, we find itin Accipiter cooperi, while in Tinnunculus sparverius and 
Polyborus tharus at least four of these vertebree form one solid bone in 
the adult specimen; in Micrastur brachypterus there are again five dor- 
sals, and all independent segments. 
Unfortunately, all that remains of our specimens of Pseudogryphus, 
so far as the vertebral column is concerned, are a few of the free ribs 
and several scattered vertebra; two of these are the third and fourth 
cervical, another one from the middle of the neck; one of the last cer- 
vicals and lastly the ultimate dorsal—this latter we have devoted a fig- 
ure to, representing as it does no doubt the largest avain vertebra of 
any living form to the northward of the range of the South American 
Condor—nevertheless, we think we may predict, almost with certainty, 
that even from these few fragmentary pieces it will be found to be the 
