906 



HISTORICAL GEOLOGY. 



From the Puerco and Wasatch beds come the earliest of the Quadrumana. 

 Fig. 1529 represents the skull of one of the species, Anaptomorphus homun- 

 cuius Cope, from the Wasatch beds of the Big Horn Basin, of Wyoming. 



1529. 



Anaptomorphus homunculus ; a, cranium, from above ; 6, same, from below, enlarged. Cope. 



Other Wasatch species include Creodonts of several genera, Insectivores, 

 and the earliest of true Rodents. There were also in the Wasatch beds, and 

 others equivalent, the first of Artiodactyl Ungxdates, the 4-toed Pantolestes 

 brachystomus of Cope, and Homacodon priscus of Marsh ; named Artiodactyls 

 (and also Paridigitates) because the foiir toes are in pairs, the third and fourth 

 being equal, and also the second and fifth if present. Examples are shown 

 in Fig. 1538. The two pairs are present in the Hog, Hippopotamus, etc. ; the 



1530. 



Eestoration of Tinoceras iugens of Marsh (x j'jj). 



