66 WONDERS OF ORGANIC LIFE. 



example, mammalia have four limbs, two on 

 each side of a central body, or, as in the whales, 

 only one on each side; birds have two wings and 

 two legs, symmetrically disposed ; many insects 

 six legs, and two or four wings, or two wings 

 with wing-covers, also symmetrical. In Crus- 

 tacea, the forms of which are often most fan- 

 tastic and extraordinary, the same rule holds 

 good. To make our meaning still clearer, let 

 our reader place before him a butterfly and an 

 oyster, and he will then have an example of 

 definiteness of form in both, but of symmetry 

 besides definiteness in the former. In the 

 vegetable kingdom, there is a greater latitude 

 both as to definite and symmetrical form than 

 in the animal kingdom. These observations 

 lead us next to the consideration of what is 

 termed specific form. 



Every species reproduces its like ; but every 

 species is subject to variety, even including 

 man, the highest of the animal creation, who 

 varies in stature, complexion, and language, 

 throughout the great divisions of the globe. It 

 is, however, to the vegetable kingdom that we 

 would here rather apply what we particularly 

 mean by specific form, because no two trees of 

 the same kind are exactly alike, no two bushes 

 are alike, no two plants are the similitudes of 

 each other. Yet in one sense they are respec- 

 tively alike ; for who would mistake the oak 

 for the ash, or the palm-tree for a pine ? After 

 its "own kind" the tree springs forth from 

 the seed, and the vital principle fails not in 



