INTRODUCTION. 



GENERAL CLASSIFICATION OF ANIMALS. 



IN order to treat clearly of the animal world, it is necessary 

 to consider it according to some method of arrangement, by 

 which those animals that most resemble one another are con- 

 nected together for the convenience of description. This ar- 

 rangement is founded upon their form and structure, and 

 separates them into various kingdoms, divisions, classes, &c., 

 according to their degree of similarity, and the points in 

 which their structures correspond. Such a system of ar- 

 rangement is called a classification of the animal kingdom, 

 and as an accurate acquaintance with the principles on which 

 it is founded is of great importance to the student of Natu- 

 ral History, a general view is here presented of that which is 

 most commonly received at the present day. 



In surveying the series of animals, from the lowest and 

 most insignificant worm up to man, the lord of the creation, 

 and examining the structure of their bodies and the mode 

 in which they are enabled to carry on the functions of life, 

 certain lines of distinction are observed among them, which 

 afford ground for arranging them, in the first place, in two 

 grand kingdoms. Those of the first grand kingdom are 

 possessed of an internal skeleton, a system of bones covered 

 by the flesh, which serves to give form, support, and strength 

 to their whole fabric, and assist in containing the various inter- 

 nal organs, whose actions keep up the life and vigor of the 

 system. Those of the second are not possessed of any such 

 skeleton, but consist of a collection of organs more or less 

 distinct, without any solid basis, and are generally of a soft, 

 yielding texture, though occasionally covered and protected 

 externally by a shell or other hard covering. It may be obr 



