TO THE LOWER ANIMALS. 83 



ences from the young ape, while the latter departs as, 

 much from the dog in its development as the man does. 



Startling as the last assertion may appear to be, it is 

 demonstrably true, and it alone appears to me sufficient to 

 place beyond all doubt the structural unity of man with 

 the rest of the animal world, and more particularly and 

 closely with the apes. 



Thus, identical in the physical processes by which he 

 originates identical in the early stages of his formation 

 identical in the mode of his nutrition before and after 

 birth, with the animals which lie immediately below him 

 in the scale Man, if his adult and perfect structure be 

 compared with theirs, exhibits, as might be expected, a 

 marvellous likeness of organization. He resembles them 

 as they resemble one another he differs from them as 

 they differ from one another. And, though these differ- 

 ences and resemblances cannot be weighed and measured, 

 their value may be readily estimated ; the scale pr stan- 

 dard of judgment, touching that value, being afforded and 

 expressed by the system of classification of animals now 

 current among zoologists. 



A careful study of the resemblances and differences 

 presented by animals has, in fact, led naturalists to ar- 

 range them into groups, or assemblages, all the members 

 of each group presenting a certain amount of definable 

 resemblance, and the number of points of similarity being 

 smaller as the group is larger and vice versa. Thus, all 

 creatures which agree only in presenting the few distinct- 

 ive marks of animality form the ' Kingdom ' ANIMALIA. 

 The numerous animals which agree only in possessing the 

 special characters of Vertebrates form one ' Sub-kingdom ' 

 of this Kingdom. Then the Sub-kingdom YERTEBRATA is 

 subdivided into the five ' Classes,' Fishes, Amphibians, 



