28 HUMBLE CREATUfiES. 



the -vvSole class. So striking is this comparative pro- 

 gress in the organization of classes and individuals, 

 that the lowest creatures in any particular section 

 strongly resemble, when in their perfect form, the 

 early or embryonic stage of the higher animals in the 

 same section, the latter undergoing various changes 

 of form and structure before they assume their cha- 

 racteristic type. 



Let us take, for example, the two groups of which 

 we are here treating, namely the AnneUdes and In- 

 sects ; the first as having been placed by Cuvier and 

 others at the base, the second as the head of the 

 Articulate division of the Animal Kingdom ; and let 

 us also select at the same time, the Worm as the 

 typical representative of the former, and the My as 

 that of the latter group. 



The Annelides have a long, soft, cylindrical body, 

 divided into rings, and furnished with no external 

 members except the rows of hooks that serve to aid 

 them in locomotion ; but as we rise in the scale of 

 Articulate animals, their bodies become shorter, and 

 are divided into distinct segments irrespective of the 

 rings, which decrease in number. The members of 

 locomotion are more prominent : first, legs appear, 

 which enable the creatures to crawl or leap ; and then 

 we arrive at the perfect insect, whose wings, super- 

 added to the legs of the lower races, impart to it also 

 the power of flight. 



And now as regards the individual. The larva of 

 the Fly, or the form in which it leaves the egg, closely 



