THE OTHER BEASTS 371 



SUB-CLASS I. PLACENTALIA continued. 



Order 6. Rodentia . . . Squirrels rats, hedge- 

 hogs, hares, &c. 



7. Ungulata Sub-order A. Bisons, antelopes, deer, 



camels, rhinoceroses, 

 horses, &c. 

 B. Hyrax. 



8. Proboscidea . . . Elephant. 

 9. Sirenia . Dugong and manatee. 



10. Cetacea .... Whales and porpoises. 

 ii. Edentata . . . Sloths, anteaters, arma- 

 dillos, pangolins. 



SUB-CLASS II. DIDELPHIA. 



Order 12. Marsupialia . . . Opossums, kangaroos, 



phalangers, &c. 



SUB-CLASS III. OENITHODELPHIA. 



Order 13. Monotremata . . . Platypus and echidna 



As to the mode of succession in which these various, 

 orders may have been evolved we can as yet only make 

 more or less plausible conjectures. 



On the whole it seems probable that the Insectivora 

 especially such a form as that spineless hedgehog, gym- 

 nura may amongst existing animals give us the best 

 general idea of primitive mammalian life. 



Certain marsupials seem closely allied to insectivores, 

 and may have been a lateral offshoot from ancestral 

 insectivorous forms. 



The platypus and echidna show characters which 

 point down below the whole class of beasts and towards 

 reptiles, but they are animals of very peculiar formation, 

 and there seem to be 110 other existing beasts which 

 have any special relationship to them, save perhaps some 

 of the edentates. But these again are specially modified 

 forms, and our speculations are here, as in so many other 

 instances, checked by the probability of the independent 

 origins of similar structures. 



