
362. THE AMERICAN NATURALIST.  [Vov. XXXVI. 
type of feet; the Australian marsupial radiation, on the other 
hand, began with a dental type similar to that of the placentals, 
LIMBS AND FEET 
VOLANT 
FOSSORIAL 
RS ae 
Short-limbed, nak 
AMBU edad ie 
impen yl, wisis 
TERRESTRIAL 
NATATORIAL 
CURSORIAL 
Amphibious Digitigrade 
Aquatic ES 
Unguligrade 
TEETH 
OMNIVOROUS ian 
HERBIVOROUS ~ Shrub 
Fruit 
Root 
MYRMECOPHAGOUS 
ee Dentition reduced 
Stem INSECTIVOROUS 
Fic. 4 ^15. 1; i 3 


Fish 
CARNIVOROUS owes 
ar 

E Bon te te 
, (6) teeth among mammals. 
but, as Dollo and Bensley have shown, the foot type was of 
highly specialized arboreal character. 
These two fundamental exceptions make clear why it is 
impossible, as MY writers have observed, to reconstruct an 

