ARTICULATA. 241 



favoured with respect to the degree in which they 

 enjoy this faculty. But the greater number of the 

 animals composing the series we are now to examine 

 are provided with a complete apparatus for motion, 

 and endowed with extensive capacities for using 

 and applying it in various ways. While Nature 

 has preserved, in the construction of their vital 

 organs, the simplicity which marks the primitive 

 modes of organization, and has adhered to a defi- 

 nite model in the formation of the different parts of 

 the system, she has displayed the most boundless 

 variety in the forms and combinations of the me- 

 chanical instruments of prehension and of pro- 

 gression . 



All the tribes of Zoophytes, and by far the greater 

 number of Mollusca, are limited, by the constitution 

 of their system, to an aquatic existence. 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 structures. A further design, also, 

 soon becomes manifest ; and instruments are given 

 for elevating the body above the ground, and for 

 traversing with rapidity the light and scarcely 

 resisting air. 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. 



VOL. I. R 



