400 



LAND MAMMALS IN THE WESTERN HEMISPHERE 



by very imperfect specimens, so that much which it would 

 be highly desirable to learn must await the finding of better 

 material. The upper molars were triangular and tritubercular, 

 i.e. with three principal cusps arranged in a triangle, and are 

 hardly to be distinguished from those of other early mam- 

 malian orders. From the teeth alone the artiodactyl nature 



of the animal would not have been 

 suspected, and, in fact, they were, 

 when first discovered, referred to primi- 

 tive monkeys. The feet probably had 

 five toes each, but this is not certain, 

 and the femur had the third tro- 

 chanter, the only known artiodactyl 

 of which this is true. As this little 

 Wasatch genus is so imperfectly known, 

 it would be premature to claim it as 

 the starting point of the 

 pm camel family, and yet it 

 may very well have been 

 so. Better material of 

 this genus and 

 the links of the 

 chain which be- 

 long in the upper 

 Bridger and the 



_ _ M M 17^ ^^"^ ^^^^^ ^®" 



Fig. 213.— Right manus of camels. A,\Protijlopus, Vi'\i\\2l. SpectlVely mUSt 

 B, tProebrotherium, White River. C, ]Procanielus, upper j-jg reCOVered be- 

 Miocene. (After Cope.) D, Recent Guanaco. 



fore this earliest 

 portion of the family history can be written in more than 

 tentative fashion. 



The mode of evolution displayed by the camels does not 

 differ in any significant respect from that seen in the horses. 

 There was the same increase in bodily stature and in the rel- 

 ative lengths of the limbs and feet, the same kind of diminu- 



B 



