586 LAND MAMMALS IN THE WESTERN HEMISPHERE 



the body being about a foot long and the tail fourteen inches, 

 and are thickly clothed with soft gray and brown fur, . . . and 

 the eyes are large and yellowish in colour, imparting the staring 

 expression of nocturnal animals of prey." ^ 



The Brazilian caverns have preserved the remains of many 

 Pleistocene monkeys belonging to existing South American 

 genera, and even several modern species are represented, while 

 others are extinct. There is also one extinct genus {^Eriodes), 

 a larger animal than any of the existing Neotropical monkeys. 

 The Pampean deposits of Argentina, on the other hand, have 

 yielded no remains of Primates, nor is this surprising, for the 

 Pampas would seem to have been open plains in the Pleistocene, 

 as they are to-day. Between the Pleistocene and the Santa 

 Cruz Miocene there is a long gap in the history. It is true 

 that some bones have been found in the Pliocene of Monte 

 Hermoso which have been referred to the Primates, but they 

 are too few and imperfect to be of any real assistance in the 

 inquiry. 



In the Santa Cruz beds fossil monkeys are very rare, but 

 that they were present in Patagonia at all, is strong evidence 

 that the climate was then far milder than it is at present. 

 These were essentially members of the modern family Cebidae. 

 The best-known genus, ^Homunculus, retained a few primitive 

 characters, which the existing genera have lost. For example, 

 the premolars were relatively smaller and of simpler form and 

 the humerus had the epicondylar foramen, though the femur 

 no longer had the third trochanter. The radius was very 

 modern in form and evidently could rotate freely upon the 

 humerus. 



No monkeys have been found in the Deseado formation, 

 though too much stress should not be laid upon this fact, 

 because of the general scarcity of small animals in those beds. 

 But the same is true of the still more ancient stages ; despite an 

 abundant and varied fauna of small mammals, they have 



1 Bates, Naturalist on the Amazons, London, 1875, pp. 332, 333. 



