SHUFELDT.] OSTEOLOGY OF THE TETRAONIDA. 699 
The os metatarsale accessorium is situated rather high upon the shaft, 
and bears more than an ordinary semblance to a demi-phalanx, with its 
distal articular trochlea. As usual it is freely attached by ligaments. 
The internodes are based upon the more common plan as applied to the 
avian foot; 7. e., in the order of the phalanges, from the first to the 
fourth, 2, 3, 4, 5 joints. They are in proportionate sizes for their sev- 
eral owners, and possess nothing peculiar about them, having all the ~ 
usual characters as found in the gallinaceous foot generally. 
They possess the usual enlarged and biconcave proximal extremities, 
with the distal and convex bitrochlear ends, with a more or less subeylin- 
drical shaft; the ungual joints being but moderately curved downwards. 
There are but few or no striking differences to be noted as existing 
among the lower extremities of our Tetraonide. 
The bones are very delicately fashioned in Canace canadensis and the 
Sharp-tailed Grouse; that is, the calibres of their shafts seem to be less 
as compared with their general lengths, but they belong, we must remem- 
ber, to very trim little game birds, as contrasted with our heavy and 
ponderous old Sage Grouse of the western prairies. Our specimens of 
Lagopus and Canace obscura do not show the bony extension from the 
tendinous process at the back of the tarso-metatarsus, apparently present 
in all the others and alluded to above—Centrocercus sometimes proving 
an exception—and this bone never normally develops a spur in any of 
our North American Grouse, as seen in birds of near kin. 
Tendons of the anti-brachium and pinion are very prone to ossify, and 
one is quite constant on the anterior aspect of the metacarpus. This 
applies with still greater force to the lower limb, where it seems that 
every tendinous extension of the muscles of thigh and leg become bone 
for their entire lengths, then forking sometimes over the fore part of 
tarso-metatarsus as they branch to be distributed to the podium. 
It may be found that Bonasa can claim normally six segments as rep- 
resenting the caudal vertebre, and we have in our possession a pelvis of 
this bird where a rudimentary second sacral rib is evident, but this can 
only be regarded in the light of an anomaly. 
The pelvic limb of the Wild Turkey has nothing about it of peculiar 
interest, 7. €., in the adult fowl, and we have never been so fortunate as 
to examine the young of this bird. The entire extremity is non-pneu- 
matic, and composed of quite powerful bones. From the lower and 
outer angles of the tendinous process of the tarso-metatarsus, a thin 
plate of bone is thrown down that gradually approaches but does not 
touch the shaft until it arrives opposite its middle, when it merges into it. 
The lower portion of this lamina bears the short spur in Pavo, but of 
my three specimens of Meleagris, no such appendage is seen; they are 
no doubt all females or perhaps young males before the development of 
the spur, as we believe old male Turkeys. always possess it. 
Interesting osseous malformations are occasionally to be seen, but they 
are beyond the jurisdiction of this monograph to treat; nor will it be 
practicable to enter into the engaging subject of the differences between 
the pelves in the male and female birds, but that such differences do 
exist there can be no reasonable doubt. 
Our Grouse and Quails all belong to the Alectoromorphe of Profes- 
sor Huxley’s classification, sharing in common with the representatives 
of that group many of their osteological characters; some of these 
characters, such as the general form of sternum, certain cranial peculi- 
arities and others, are positively distinctive and differ from all other 
groups. Our Tetraonide, with the exception of Pediccetes, and Oupi- 
donia, have certain similarities or osteological resemblances found 
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