ARTICULATA. 269 



has adhered to a definite model in the foniiation of 

 the different parts of the system, she has nowhere 

 displayed more boundless variety in the combin- 

 ations of the forms which she has impressed 

 upon the mechanical instruments, both of pre- 

 hension and of progression. 



All the tribes of Zoophytes, and by far the 

 greater number of Mollusca, are limited by the 

 constitution of their system, to an aquatic exist- 

 ence. But in following the series of Articulated 

 animals, we very soon emerge from the waters, 

 and find structures adapted to progression on 

 land. For this we see that preparation is early 

 made in the developement of the nascent struc- 

 tures. A farther design, also, soon becomes 

 manifest ; and instruments are given for ele- 

 vating the body above the ground, and for 

 traversing with rapidity the light and scarcely 

 resisting atmosphere. This prospective design 

 may be traced in the whole system of insects ; 

 every part of which is framed with reference to 

 the properties of the medium through which 

 these movements are to be performed. 



§ 2. Annelida. 



The lowest division of articulated animals com- 

 prehends those which have a vermiform shape, 

 and which compose the class of Annelida, or 

 Annulose animals ; of which the earth-worm 



