PEDIGREE OF BIRDS. 267 
The obscurity which surrounded these parts of the old 
antediluvian birds has been cleared up by a discovery by 
the American naturalist, Marsh, He found in the upper 
Chalk of Kansas the remains of. two genera of birds, 
which by their bi-concave vertebre remind us of the 
characteristics of the ancient reptiles, and by this alone 
present extremely valuable intermediate stages, but 
which, moreover, bore teeth in both jaws. These teeth 
are small and sharp, and were so numerous that in the 
lower’ jaw of the animal named Ichthyornis dispar, 
twenty might be counted on each side, * 
‘Thus we are now quite clear as to the kinship of the 
bird. It-is a reptile adapted to aerial life, and those 
birds which we see more estranged from flight have 
acquired the characters correlated with more or less 
incapacity for flight only by means of retrogression. It 
fares the worse with the internal arrangement of this 
class'of animals. Partly from. their geographical distri- 
-bution, ‘partly from anatomical indications, especially of 
the skull, it may be inferred that the ostrich-like birds 
are not, in-virtue of their strength of ‘leg and adeptness 
in running, the youngest members of their class and the 
most nearly allied to the mammals, but that they are 
the oldest’of those now living: The nature of the 
‘imperfection of their wings shows, as we have said, that 
they are in a state of arrest or retrogression. Beyond 
this ‘general: experience it is impossible togo. If we 
contempiate:the bird as a flying animal, those of course 
rank highest which have learnt to fly the best. This 
palm: avowedly accrues to the birds of prey as a whole, 
although other orders are not deficient in pre-eminent 
flyers. Brehm and others hold the parrots, because 
