4 ON CLASSIFICATION. 



skeleton. The nervous centres consist of several detached masses 

 placed in different parts of the body, without regularity of distribution 

 or symmetrical arrangement ; and the entire group is obviously natural, 

 although Cuvier has ranged in it some creatures which, in the structure 

 of their nervous system, differ essentially from those comprised in his 

 own definition. 



(8.) The class of ARTICULATED ANIMALS is likewise well characterized 

 by the nervous system, which, in all the members of it, is composed of 

 a double series of ganglia or masses of neurine, arranged in two parallel 

 lines along the abdominal surface of the body, united by communicating 

 cords, and from which nerves are given off to the different segments of 

 which the body consists. 



(9.) The fourth division of Cuvier, namely that of ZOOPHYTES or 

 RADIATED ABTIMALS, is confessedly made up of the most heterogeneous 

 materials, comprising creatures differing in too many important points 

 to admit of their being associated in the same group ; and the efforts of 

 subsequent zoologists have been mainly directed to the establishment 

 of something like order in this chaotic assemblage. 



(10.) The evident relation which the perfection of the nervous system 

 bears to that of animal structure, and the success of Cuvier in selecting 

 this as the great point of distinction in the establishment of the higher 

 divisions of the animal kingdom, necessarily led succeeding naturalists 

 still to have recourse to this important part of the economy in making 

 a further subdivision of the Radiata of Cuvier. In some of the radiated 

 forms, indeed, nervous filaments are distinctly visible, and such are 

 among the more perfectly organized of the group ; these, therefore, have 

 been classed by themselves, and designated by Professor Owen the 

 NEMATONEUROSE* division of the animal world; while those which are 

 apparently without the least trace of distinct nervous matter have been 

 formed by Mr. Macleay into a group by themselves, to which he has 

 given the denomination of AcRiTAf. 



(11.) There can be no doubt that the nervous matter must be re- 

 garded as the very essence or being of all creatures, with which their 

 sensations, volition, and capability of action are inseparably connected ; 

 and such being the case, it is a legitimate inference that the capacities 

 and powers of the several tribes are in immediate relation with the de- 

 velopment and perfection of this supreme part of their organization, 

 and their entire structure must be in accordance with that of the 

 nervous apparatus which they possess. The nature of the limbs and 

 external members, the existence or non-existence of certain senses, the 

 capability of locomotion, and the means of procuring food must be in 

 strict correspondence with the powers centered in the nervous masses of 

 the body, or in that arrangement of nervous particles which represents 

 or replaces them. 



, a thread ; vevpov, a nerve. t a priv. ; Kplvw, to discern. 



