PART II. 



VERTEBRATED ANIMALS 



196. VERTEBRA, signifies " back bone, and the animals 

 which come next to the insects in the scale of organi- 

 zation, are called vertebrated, that is, they have back 

 bones. 



197. The animals we have heretofore examined consist 

 of those which have no hard parts, as the 'polypi, or those 

 covered with shells, as the mollusca, or with a crust, as the 

 Crustacea, or such as pass from the soft to a more consistent 

 state, as the insecta. 



198. None of these animals possess an internal solid 

 frame-work to support and connect the softer parts, this 

 kind of structure being reserved for animals of the higher 

 orders, and more complex organizations. 



199. " If," says Roget, " it be pleasing to trace the foot- 

 steps of nature in constructions so infinitely varied as those 

 of the lower animals, and to follow the gradations of as- 

 cent from the zoophyte to trie winged insect, w r hich ex 

 nibits the greatest perfection compatible with the restricted 

 dimensions of that class of beings, still more interesting 

 must be the study of those more elaborate efforts of crea 

 tive power, which are displayed on a wider field in tht 

 higher orders of the animal kingdom. In the various tribes 

 of beings which are now to come before us, we find na- 

 ture proceeding to display more refined developments in 



What are vertebrated animals? How are the vertebrated animals espe- 

 cially distinguished from those we have already examined? 



