ON CLASSIFICATION. 5 



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

 been classed by themselves, and designated by Mr. 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. M'Leay into a group by them- 

 selves, to which he has given the denomination of ACRITA.J- 



(7.) There can be no doubt that the nervous matter must be 

 regarded 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 im- 

 mediate relation with the developement 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 nonexistence of certain senses, the capability of loco- 

 motion, and the means of procuring food, must be in strict cor- 

 respondence with the powers centred in the nervous masses of 

 the body, or in that arrangement of nervous particles which 

 represents or replaces them. 



Granting the accuracy of the above view, it is obvious, that 

 if exactly acquainted with the structure and elaboration of the 

 nervous apparatus in any animal, we might to a great extent pre- 

 dicate the most important points in its economy, and form a 

 tolerably correct estimate of its powers and general conformation. 

 But, unfortunately, such knowledge is not always at our disposal : 

 in the lower forms of the animal world especially, we are far from 

 being able to avail ourselves of such a guide, and it will probably 

 be long ere our improved means of research permit us to apply to 

 practice the views which Physiology would lead us to adopt. 



The grand divisions of the animal kingdom, grounded upon the 

 principal varieties in the arrangement of the nervous system, we 

 shall, however, proceed to consider, leaving to future occasions 

 those comments which a consideration of the structure of par- 

 ticular groups will force upon our notice. 



, a thread ; N-upov, a nerve. t , priv.; notva, to discern. 



