FOSSIL BIRDS 



537 



While in former times existing birds were divided into a 

 large number of " orders," these are now known to be sub- 

 divisions of sub-classes or orders — i.e., sub-orders (the latter 

 category is adopted in this book), and probably in many cases 

 should be honored only with the rank of families. The 

 discovery of the Archwoptery.v and of birds with teeth and 

 biconcave vertebrje has essentially modified prevailing views 

 as to the classification of birds. 



Order 1. Saururce. — The oldest bird, geologically speak- 

 ing, is the ArchcBopteryx (Fig. 460) of the Jurassic slates of 

 Solenhofen, Germany. This was a bird about the size of a 

 crow, the tail being 22 cent. (8-9 inches) long, but longer 



Fig. 460. — Kestoration of Archtmpieryx macrura. — After Owen, from Nicholeon. 



than the body, supported by many movable vertebra? and 

 covered with feathers in distichous series, not in the shape 

 of a fan. The jaw-bones were long, and probably contain- 

 ed teeth. In this respect and in the long tail the creature 

 served as a connecting link between the reptiles, such as 

 the bird-like CompsogiiatJms and the existing birds. The 

 hind legs and wings have the ordinary bird structure, 

 though the metacarpal bones were not co-ossified ; the foot 

 consisted of four digits. 



Order 2. OdontornWies. — Still another connecting link 

 between the reptiles and birds has been discovered by Marsh 



