254 ON THE RELATIONS OF MAN 



Birds, and Mammals, and these into smaller groups called 

 ' Orders ' ; these into ' Families ' and ' Genera ' ; while the 

 last are finally broken up into the smallest assemblages, 

 which are distinguished by the possession of constant, not- 

 sexual, characters. These ultimate groups are Species. 



Every year tends to bring about a greater uniformity 

 of opinion throughout the zoological world as to the limits 

 and characters of these groups, great and small. At 

 present, for example, no one has the least doubt regarding 

 the characters of the classes Mammalia, Aves, or Reptilia ; 

 nor does the question arise whether any thoroughly well- 

 known animal should be placed in one class or the other. 

 Again, there is a very general agreement respecting the 

 characters and limits of the orders of Mammals, and as to 

 the animals which are structurally necessitated to take a 

 place in one or another order. 



No one doubts, for example, that the Sloth and the 

 Ant-eater, the Kangaroo and the Opossum, the Tiger and 

 the Badger, the Tapir and the Rhinoceros, are respectively 

 members of the same orders. These successive pairs of 

 animals may, and some do, differ from one another im- 

 mensely, in such matters as the proportions and structure 

 of their limbs ; the number of their dorsal and lumbar 

 vertebrae ; the adaptation of their frames to climbing, 

 leaping, or running ; the number and form of their teeth ; 

 and the characters of their skulls and of the contained 

 brain. But, with all these differences, they are so closely 

 connected in all the more important and fundamental 

 characters of their organization, and so distinctly separated 

 by these same characters from other animals, that zoologists 

 find it necessary to group them together as members of one 

 order. And if any new animal were discovered, and were 

 found to present no greater difference from the Kangaroo 

 and the Opossum, for example, than these animals do from 

 one another, the zoologist would not only be logically 

 compelled to rank it in the same order with these, but he 

 would not think of doing otherwise. 



Bearing this obvious course of zoological reasoning 

 in mind, let us endeavour for a moment to disconnect 

 our thinking selves from the mask of humanity ; let us 

 imagine ourselves scientific Saturnians, if you will, fairly 

 acquainted with such animals as now inhabit the Earth, 

 and employed in discussing the relations they bear to a 

 new and singular ' erect and featherless biped,' which some 



