GENERAL CHARACTERS OF THE ANNULOSA. 8 



until, on arriving at the furthest limits of the class, there 

 is nothing to remind us of the typical annulose structure 

 but a long slender body, pointed at both ends, like the 

 common earth-worm, moving about by the action of the 

 circular rings or joints (often very obscure), of which it 

 is composed. Some of the remote Annulosa externally 

 resemble shellfish, and live in the water : others are 

 parasitic, like the Cirrhipedes, or, like the worms, are 

 destitute of limbs; while another large group, in addition 

 to the most eccentric shapes, differ from all the preced- 

 ing by having red blood, and by living either in the ocean 

 or in moist earth. All these, however widely they differ 

 from the pre-eminent types of this assemblage, are clearly 

 formed upon the same general model : their body is di- 

 vided into joints, more or less conspicuous, nor do they 

 differ more among themselves than do the various classes 

 of the vertebrate circle. Annulose animals are not only 

 the most diminutive in size of all creeping things, but 

 they are, beyond all comparison, more numerous than 

 the vertebrate class. When we consider the surprising 

 habits of the insect world in general, the high develop- 

 ment of instinct which is found among whole families, 

 the activity of motion, the beauty of form, and the re- 

 splendent colours which nature has so lavishly bestowed 

 upon these pigmy creatures, we cannot for a moment 

 hesitate to place them next in the scale of creation to the 

 vertebrate animals, a station which we shall presently 

 show they are entitled to hold on other and more weighty 

 considerations. 



(4.) Independent, however, of the foregoing characters, 

 which stamp *a peculiarity upon the insect world, there 

 is yet another nearly as important, which equally sepa- 

 rates them. This is found in the extraordinary meta- 

 morphosis, or change of form, which all the typical, and 

 some of the aberrant, groups undergo previous to arriving 

 at their perfect state. The only other animals in crea- 

 tion which are known to participate in this character are 

 the frogs, among the reptiles, arid these are the most im- 

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