PEDIGREE OF BIRDS. 265 
or lizard-like animals. The scale of a lizard and a 
feather seem to be totally different things; but in their 
first rudiments they are completely identical, and the 
feather has a far greater analogy with the scale, than with 
the hair. The plumage, which seems to impress a spe- 
cific character upon the bird, is therefore to be traced 
from the formation of scales. Of the internal soft organs, 
we will only remark upon the heart and lungs. All the 
older geologists placed the heart of the bird on the same 
level with that of the mammal and of man ; in its specific 
arrangements, however, it is only to be interpreted by 
the heart of the reptile, and the wind-pipe is not ramified 
asinthe mammal, That the reptiles exhibit a gradual 
transition to the leg of the bird, has been repeatedly 
pointed out. The pelvis of the bird, which is remarkable 
for the length of the pubis and ischium, and is open in 
front, likewise represents only a slight advance in develop- 
ment upon the pelvic structure already shown in several 
of the Ornithoscelidz. Thus Huxley says with reference 
to the ischium of the Hypsilophoda, that “the remark- 
able slenderness and prolongation of the ischium give it 
a wonderfully ornithic character.” Finally, in the skull, 
peculiarities possessed by the bird in contrast with the 
mammal, such as the simple condyle of the occiput, the 
quadrate bone, the cochlea of the auditory labyrinth, the 
composition of the lower jaw, its articulation with the 
skull by the intervention of the quadrate bone, &c., are 
not specific characters of the bird alone, but of reptiles in 
general. This similarity of type in reptiles and in birds 
's perfectly manifest from the comparison of living birds 
with living reptiles. But the proof that the bird is 
derived from the reptile is rendered unimpeachable by 
