CHAPTER VI. 



ON THE ORDERS OF THE ANNULOSA. 



Aristotle appears to have comprehended under the 

 general title of "Evro^a. not only true Insects and Arach- 

 nida, but also some modern Annelides and Worms. Now, 

 as they have nothing in common but their longitudinal 

 knotted nervous system, which he cannot be supposed to 

 have detected, and their annular structure, it is manifest that 

 the founder of Zoology must have had an indistinct per- 

 ception of the natural character of such a group being 

 external articulation. He even expressly says that on this 

 account he gave them their name; yet his perception of 

 the truth I conceive must have been indistinct, because 

 he has separated from these animals the modern Crustacea, 

 which are as truly articulated as any of the foregoing. 

 This separation of the Crustacea from the other Annulose 

 animals originated in his unfortunately making the first 

 great division of Zoology depend on the medium inhabited ; 

 and his reason for continuing in the error becomes appa- 

 rent as soon as we observe from the name which he gives 

 to the Crustacea, {MuXuxoa-Tpaxa. or Soft-shelled Testacea,) 

 that he considered them merely, as the vulgar do at this 

 day, to be a sort of Shell-fish whose testaceous covering 

 is softer than ordinary*. Nor indeed do the ancient na- 



* As he placed the Crustacea between the Mollusca (tk Orgtxxfi^M*) and 

 the Cephalopoda (to MaXaKta), he also called them, in opposition to these 

 last, SxXM^Ssjaa. They were with him soft-shelled TeUacea and hard- 

 skinned Cephalopoda. 



