634 



MANUAL OF ZOOLOGY. 



known birds, living or extinct, and two of the digits appear to 

 have been ungniculate. 



The sub-class Saurornithes includes only the single order 

 Saurura, of which no other representative is known than the 



Fig. 351. ArcJuzopteryx macrura, showing tail and tail-feathers, with detached bones. 



Jurassic Archaopteryx. From the presence of feathers it may 

 be inferred that Archaopteryx was hot-blooded, and this char- 

 acter, taken along with the structure of the extremities, is 

 sufficient to justify the reference of this unique fossil to the 

 Birds. In the long lizard-like tail, composed of numerous free 

 vertebrae, each of which bears a pair of tail-feathers, in the fact 

 that the metacarpals were not anchylosed together, and in the 

 possession of two free clawed digits to the manus, Archceopteryx 

 differs from all other known birds, living or extinct. There is 

 also some reason to believe that the jaws were furnished with 

 teeth sunk in distinct sockets. 



SUB-CLASS IV. ODONTORNITHES. 



ORDER I. ODONTOLC^E. This order has been founded by 

 Marsh for the reception of the extraordinary Hesperomis 

 regalis, from the Cretaceous rocks of North America. In 

 this wonderful fossil we have a gigantic diving-bird somewhat 

 resembling the true "Divers" or " Loons " (Colymbus), but 

 having the jaws furnished with numerous conical recurved 

 teeth, sunk in a deep continuous groove (fig. 352, b and d\ 



The front of the upper jaw does not carry teeth, and was 

 probably encased in a horny beak. The breast-bone is entirely 



