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No Artiodaetyla except Microtragulus (cf. Hypisodus and other Hyper- 
tragulidse). 
In the lowest level (Entrerian) the admixture of Santa Cruz genera is 
large, forming the major part of the fauna. 
B. Middle and Upper Pampean. 
This is the Pampean (Ensenadan and Bonserian) of Ameghino. 
Carnivora. 
Smilodon, Felis. 
Canis, Paloeocyon, Dinocynops (cf. Lycaon 1 ). 
Arctotherium, Pararctotherium. 
Conepatus (in upper levels only). 
Rodentia. 
Cricetidse (Necromys etc.). 
Dolichotis, Viscaccia, Hydrocheerus, Ctenomys, Myopotamus and other 
Hystricomorph genera, mostly still living. 
Edentata (Gravigrada). 
Megatherium, Mylodon, Lestodon, Glossotherium, Scelidotherium. 
(Glyptodontia.) 
Glyptodon, Panochtus, Dcedicurus, Hoplophorus etc. 
(Dasypoda.) 
Dasypus, Zaedyus, Tatusia, Eutatus, Chlamydophorus etc. 
Proboscidea. 
“ Mastodon” (all Dibelodon, auct. R. S. Lull). 
Toxodontia. 
Toxodon. 
Typotherium and Pachyrucos in lower beds only. 
Litopterna. 
Macrauchenia. 
Peris sodactyla. 
Tapirus in lower levels. 
Equus only in upper levels. 
Hippidion, Onohippidion (derivatives of Pliohippus of North America). 
1 The occurrence in the Pampean of a species so closely allied to the South African genus 
Lycaon might seem evidence for a South Atlantic land bridge in the late Tertiary, but in fact, 
Lycaon, Icticyon and Cyon of S. Africa, Brazil and the East Indies are survivors of a group of 
Canidse well known from the Oligocene and Miocene of North America. Dinocynops is in all 
probability a fourth descendant of the same group. All are distinguished by trenchant heels 
on the lower molars, disappearance of intermediate cusps on upper molars, tendency to reduce 
the tubercular dentition, short deep muzzle, and various other characters. Paloeocyon Lund 
(not of Ameghino) is perhaps a member of the same group. 
