PART II. 



VERTEBRATED ANIMALS. 



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. 



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 Jnsecta. 



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. 



" 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 ascent from the Zoophyte to the winged insect, which 

 exhibits 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 creative power, which are displayed on a 

 wider field in the higher orders of the animal kingdom. 

 In the various tribes of beings which are now to come 

 before us, we find nature proceeding to display more 



What are vertebrated animals 7 How are the vertebrated animal* 

 specially distinguished from those we have already examined? 



