III.] INDErENDENT SIMILARITIES OF STRUCTURE. 81 



Mjitnmals' arc divisible into one great group, -which 

 comprises the immense majority of kinds termed, from 

 their mode of repTCKhxci'iou, j>lace7ital 3Iam,7nah^ and into 

 nnoUicr very much smulhT group comprising the pouched- 

 beasts or marsupials (wliich are the kangaroos, bandicoots, 

 phalangers, etc., of Australia), and the true opossums of 

 America, called imjylacental Ilanimals. Now, the ])laccn- 

 tal mammals are subdivided into various orders, amonnr 

 which are the flesh-eaters (Carniv^ora, i. e., cats, dogs, ot- 

 ters, weasels, etc.), and the insect-eaters (Insectivora, i. c., 

 moles, hedgehogs, shrew-mice, etc.). The marsupial mam- 

 m.'ds also present a variety of forms (some of which are 

 carnivorous beasts, while others are insectivorous), so 

 marked that it has been even proposed to divide them into 

 orders parallel to the orders of placental beasts. 



The resemblance, indeed, is so striking as, on Darwinian 

 principles, to suggest the probability of genetic affinity ; 

 and it even led Prof. Huxley, in his Hunterian Lectures, in 

 18GG, to promulgate the notion that a vast and widely-dif- 

 fused marsupial fauna may have existed anteriorly to the 



TEEXn or UROTBIOnTIS AND TERAMELES 



development of the ordinary placental, non-pouched beasts, 

 and that the carnivorous, insectivorous, and herbivorous 



3 I. c, warm-blooded animals which suckle their younp, such as apes, 

 bats, hoofed beasts, lions, dogs, bears, weasels, rats, squirrels, armadillos, 

 sloths, whales, porpoises, kangaroos, opossums, etc. 



