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 vertebrae 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 ac- 

 quired the characters correlated with more or less in- 

 capacity 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 to go. If we 

 contemplate 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 



