28 



MAMMALIA 



CLASS V 



greatly varying size. Bipilus, Metriodromus, Halmaselus, Pichipihis, Essoprion 



Ameghino are imperfectly known. Palaepanorthus Ameghino. Lower Miocene 



(Pyrotherian beds). 



Subfamily 3. Abdbritinae. 



? ? ? ? 



' ' . P^ enlarged, lower M-^ developed as cutting tooth with grooves on either 



side ; the remaining M are bimolophodont and quadriticbercular. 



The lower M-^ has a marked resemblance to P^ of Allotheria, but possesses 

 a heel which is but weakly developed in the forms from the Colpodon beds. 

 Miocene of Patagonia. 



Ahderites Ameghino (Fig. 44). Be- 

 tween I^ and the small transversely 

 placed P^ are four intermediate teeth. 

 Miocene ; Santa Cruz. 



Parabderites Ameghino. Between /^ 



Fig. 43. 



Callonurms robiistus Ameghino. Inner aspect 

 of lower jaw. i/i. Upper Sliocene of Sautu Cruz, 

 Patagonia. 



Fio. 44. i 



Abderites meridionalis Ameghino. A , Inferior aspect 

 of upper jaw, i/j. B, Exterior aspect of same, i/i. 

 C, Exterior aspect of lower jaw, s/g. Upper Miocene 

 of Santa Cruz, Patagonia. 



and the rather large P^ are five intermediate teeth. Colpodon and Pyrotherian 

 beds (Miocene). 



Family 2. Phalangeridae. 



Diversely specialised marsupials, some omnivorous, some herbivorous, adapted partly 



for leaping, partly for climbing, and even sometimes for flying. Dentition never 



3.1.3-1.4. 

 complete. T7P5^t~i'- Upper D larger than the rest, lower I horizontal and 



rodent-like. Upper C always small; P^ in both jaws almost always trenchant, 

 usually grooved, or else all P are M-like. M quadricuspidate, tubercles of unif&)-m 

 size and united in pairs. Fore limbs generally shorter than hind; the fourth 

 digit is always the most strongly developed. Second and third digits reduced and 

 enveloped in a single fold of skin. Tail mostly long and powerful, and used partly 

 as prehensile oi-gan, partly fvr diminishing speed. 



Recent in Australia and in parts of New Guinea. Fossil in the Pleistocene 

 of Australia. 



Subfamily 1. Hypsiprymxinae. Kangaroo-rats. 



3.1.1.4. 

 Long-snouted marsupials, not larger ilian a rabbit, f A i q T- A' ^'^ ^^^^^ 



jaws, trenchant and channelled on both sides. Limbs of equal length. Pes usually 

 pentadactyl. 



