ZOOPHYTES. 133 



produced by a separate and distinct organ. In 

 some, the leading principle of the construction is 

 simplicity ; in others, the most elaborate mechanism 

 is displayed ; but the means have constant refer- 

 ence to the design, and are ever varied in exact 

 conformity with the change of purpose. The rela- 

 tive advantages of each plan of structure appear to 

 have been carefully estimated, and studiously ba- 

 lanced. Each quality has been bestowed in dif- 

 ferent degrees of perfection ; so that in following 

 the series of gradation among the successive tribes 

 of animals, we occasionally meet with favoured 

 species, endowed with great superiority in some 

 particular faculty. Some animals excel in swift- 

 ness ; others in strength. Some are formed to dive 

 into the recesses of the deep ; others to flutter in the 

 light regions of air ; while, in many of the inferior 

 ranks, we find all these objects renounced for the 

 more certain advantage of security, which the softer 

 texture of the organs renders one of paramount im- 

 portance. That construction of limbs which fa- 

 vours certain movements will necessarily interfere 

 with the ready performance of others, and must 

 preclude the developement of the organs which 

 would be necessary for facilitating them. Different 

 kinds of prey require dexterity in particular actions 

 for their pursuit and seizure. The animal is, in 

 one case, formed for climbing trees ; in another, for 

 burrowing in the earth : in a third, for perforating 

 wood. Some are provided with organs for pene- 

 trating into the bodies of other animals; others 

 with the means of ensnaring their captives ; while 

 others, again, instil into the veins of their victims a 

 deadly poison. Hence it is necessary, in studying 



