DEFINITION OF BIRDS'. 



63 



ichnites, — the fossils so called because supposed to iudicate the presence of Birds hy tlicir 

 foot-prints, were discovered abtiut the year 1835 in the Triassic formation in Connecticut. 

 But the creatures which made these tracks are now reasonably believed to have been all 

 Dinosaurian Reptiles. The oldest ornitholite, or fossil certainly known to be that of a true 

 Bird, is the famous Arclueojitenjx, found by Andreas Wagner in 1861 in the Oolitic slate (jf 

 Solenhofen in Bavaria. This has a long lizard-like tail of twenty vertebra?, from each of which 

 springs a well-developed /eaWier on each side; feathers of the wings are also well preserved; 



Fig. 15. — Restoration of Hesperornis regalls. After ^larsh. 



bones of the hand are not fused together, as they are in recent Birds ; and the jaws bear true 

 teeth. This Bird has served as tlic basis of one of the primary divisions of the class Aves : 

 though it has many reptilian characters, it is a true Bird. The great ga]) between this ancient 

 Avian and latter-day birds has been to some extent bridged by Marsli's discovery and splendid 

 restoration of Birds from the Cretaceous formations of North America, such genera as 

 Ichthyornis and Hesperornis forming types of two other primary divisions of the class, Odon- 

 totormee and Odontolcce, or Birds with teeth in s<ickets, and those with teeth in grooves. In 

 both genera the tail is short, as in ordinary birds. In Ichthi/omis, thougli the wings are 



