200 



DINOSAURS OF NORTH AMERICA. 



the main characters of the animal can be determined with considerable 

 certainty. 



A study of these remains shows that the reptile they represent was 

 one of the typical Oruithopoda, and one of the most bird-like yet dis- 

 covered. A dentary bone in fair preservation (fig. 42) indicates that 

 the animal was herbivorous, and the single row of pointed and com- 

 pressed teeth, thirteen in number and small in size, forms a more regu- 

 lar and uniform series than in any other member of the group. The 

 ilium, also, shown in fig. 43, is characteristic of the Oruithopoda, having 

 a slender, pointed process in front, butoue much shorter than in any of 



42 



43 



Fig 42. — Dentary bone ol' Xanosaiirus agilis JIarsb ; seeu from the left. 



Fig. 43.— Ilium of same individual ; leftside. 



Botli figures are natural size 



Fig. 44. — Left femur of Nanosaurus rex Marsh; front view. 



Fig. 45 —Proximal end of same. 



Fig. 46.— The same bone; side view. 



Fig. 47. — The same; back view. 



Fig. 48.— Distal end of same. 



All five figures are one-half natural size. 



the larger forms. The posterior eud is also of moderate size. All the 

 bones of the limbs and feet are extremely hollow, strongly resembling 

 in this respect those of birds. The femur was shorter than the tibia. 

 The metatarsals are greatly elongated and very slender, and there were 

 probably but three functional toes in the hind foot. 



A second form referred by the writer to this genus, under the name 

 Nanosai rus rex, may perhaps belong to the genus Laosaurus. The 

 femur is shown in figs. 44 to 48, above. The animal thus represented 



