204 Bulletin American Museum of Natural History. [\o\. XXVII, 



PERAMELOIDEA. 



"Properamelid.e" Bensley (hypothetical). 

 (Derived from primitive Didelphiidse). 

 Arboreal to terrestrial. 



Pes narrow, with beginnings of syndactyly; hallux, opposable but 

 small, digit IV bigger than II, II = III. 

 Insectivorous. 



Polyprotodont. 



Molars tritubercular, bunodont. 

 Peramelid.e. 



(Derived from Properamelidse) . 



Terrestrial, semifossorial, cursorial. 

 Size and form rabbit-like. 

 Tail non-prehensile, hairy. 

 Pes narrow, elongating, finally macropodiform, hallux reduced, 



finally to zero. 

 Pes syndactylous, digits II and III becoming vestigial, IV increas- 

 ing. 

 Plantar pads in pes becoming reduced. 

 Digits in manus becoming reduced, either after the mesaxonic 



{Perameles) or paraxonic fashion (Chaeropus). 

 Fossorial, ungues deeply cleft. 



Gait cursorial, subplantigrade to extreme digitigrade. 

 Inseetivorous-omnivorous {vegetarian) . 

 Polyprotodont, I ^. 



Molars tri- to quadritubercular, bunodont to hypsodont, metacone 

 (as in Artiodactyls) finally replacing hypocone (Thylacomys). 

 Per a gale, Perameles, Choeropus. 

 NOTORYCTOIDEA. 



"Pronotoryctids" hypothetical). 



(Derived from Properamelidse : Bensley, Dollo). 

 Terrestrial, fossorial. 



Pes broad, with incipient syndactyly, hallux opposable. 

 Insectivorous. 



Polyprotodont. 



Molars tritubercular, paracone and metacone appressed. 



Talonid of lower molars reduced (correlated with shortened skull). 



NOTORYCTID.E. 



(Derived from "Pronotoryctids")- 

 Terrestrial, fossorial. 



Pes very broad, with vestigial syndactyly. 

 Form Chrysochloris-like. 

 Insectivorous-vermivoroiis. 



Polyprotodont I ~, P j^. 



Upper molars somewhat resembling those of Chrysochloris: para- 

 cone and metacone fused into a single high piercing cusp, 

 protocone (plus hypocone ?) low. Talonid of lower molars 

 absent. 

 Notoryctes. 



