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by its external condyle, which instead of having in its back part a 
simple convexity for the outer pit of the head of the tibia, has two 
projecting lines : the one, which is the real condyle, and which 
answers to the upper and outer pit of the tibia, and to the inner pit 
of the fibula, is stronger marked than the other, which is more external, 
descends less, and rests on the upper edge of the fibula. Thus the 
external condyle, in birds, is forked, or hollowed out into a canal 
more or less deep, in its back part. 
The only quadruped, in which any analogous structure is discover- 
able, is the kanguroo. In this animal there exists a slight depression 
on the back part of the external condyle of the os femoris ; but the 
great width of the great trochanter, and several other characters, will 
always prevent the confounding of the os femoris of a bird with that 
of a kanguroo. 
Reckoning upon the apparent specific characters of different thigh - 
bones, found in the neighbourhood of Paris, M. Cuvier concludes that 
they point out the remains of five or six different species of birds 
existing in these quarries. 
The shoulder-bones of birds are also easily known, by the particular 
characters of their extremities. The head is always oblong, from right 
to left, playing in a corresponding groove formed by the scapula and 
clavicle ; the two lateral ridges widening this part of the bone con- 
siderably. The lower end is distinguishable by an articular pulley, 
divided into two parts : one of which, the inner or lower, which is 
nearly round, is for articulation with the ulna; and the other, the 
outer or upper, which is oblong in the direction of the bone, and rises 
a little obliquely on the anterior face of the bone, is for the radius. In 
quadrupeds, the head is always round and the ridges small ; and in the 
lower end, the ulnar pulley is always concave, and the radial is hol- 
lowed into a groove in those in which the fore -arm has no supination. 
By nice investigation and comparison, M. Cuvier is supported in his 
conjectures, that he has found the mineralized remains of a pelican less 
