OP.IGIN OF THE ANIMATED TRIBES 



99 



iosophical in the idea of a new creation, will be disposed 

 to think that there is less difficulty in believing in such a 

 creation having actually taken place, than in believing 

 that, in two instances separated in place and time, exactly 

 the same insects should have chanced to arise from con- 

 cealed ova, and these a species heretofore unknown. 



HYPOTHESIS OF THE DEVELOPMENT 



OF THE VEGETABLE AND ANIMAL KINGDOMS. 



It has been already intimated, as a general fact, that 

 there is an obvious gradation among the families of both 

 the vegetable and animal kingdoms, from the simple 

 lichen and animalcule respectively up to the highest order 

 of dicotyledonous trees and the mammalia. Confining 

 our attention, in the meantime, to the animal kingdom — 

 it does not appear that this gradation passes along one 

 line, on which every form of life can be, as it were, 

 strung ; there may be branching or double lines at some 

 places, or the whole may be in a circle composed ot 

 minor circles, as has been recently suggested. But still 

 it is incontestable that there are general appearances of a 

 scale beginning with the simple and advancing to the 

 complicated. The animal kingdom was divided by C uvier 

 into four sub-kingdoms, or divisions, and these exhibit an 

 unequivocal gradation in the order in which they are here 

 enumerated : Radiata (polypes, &c. ;) mollusca (pulpy 

 animals ;) articulata (jointed animals ;) vertebrata (ani- 

 mals with internal skeleton.) The gradation can, in like 

 manner, be clearly traced in the classes into which the 

 sub-kingdoms are subdivided, as, for instance, when w r e 

 take those of the vertebrata in this order — reptiles, fishes, 

 birds, mammals. 



While the external forms of all these various animals 

 are so different, it is very remarkable that the whole are, 

 after all, variations of a fundamental plan, which can be 

 traced as a basis throughout the whole, the variations be- 

 ing merely modifications of that plan to suit the particu- 

 lar conditions in which each particular animal has been 

 designed to live. Starting from the primeval germ, which 

 as we have seen, is the representative of a particular order 



