206 THE STUDY OF ZOOLOGY vii 



complex is ever^^vhere evolved out of the simple. 

 Every animal has at first the form of an egg, and 

 every animal and every organic part, in reaching 

 its adult state, passes through conditions common 

 to other animals and other adult parts ; and this 

 leads me to another point. I have hitherto 

 spoken as if the lobster were alone in the world, 

 but, as I need hardly remind you, there are 

 m3rriads of other animal organisms. Of these, 

 some, such as men, horses, birds, fishes, snails, 

 slugs, oysters, corals, and sponges, are not in the 

 least Hke the lobster. But other animals, though 

 they may differ a good deal from the lobster, are 

 yet either very hke it, or are hke something that 

 is hke it. The cray fish, the rock lobster, and the 

 pra^vn, and the shrimp, for example, however 

 different, are yet so hke lobsters, that a child 

 would group them as of the lobster kind, in contra- 

 distinction to snails and slugs ; and these last again 

 would form a kind by themselves, in contradis- 

 tinction to cows, horses, and sheep, the cattle kind. 



But this spontaneous grouping into " kinds " is 

 the first essay of the human mind at classification, 

 or the calhng by a common name of those things 

 that are ahke, and the arranging them in such a 

 manner as best to suggest the sum of their hke- 

 nesses and unhkenesses to other things. 



Those kinds which include no other subdivisions 

 than the sexes, or various breeds, are called, in 

 techni<;al language, species. The Enghsh lobster 



