282 REVIEWS — PRINCIPLES OP ORGANIC ARCHITECTURE. 



pect of the animal. On the other hand, although these several systems 

 agree in many of their relations in the two groups, in some points they 

 are as strikingly contrasted. Thus the skeleton, which ia mostly con- 

 fined in Vertebrata to the interior of the body, is wholly external in 

 Articulated animals, so that the jointed character is at once apparent 

 in them, while in the former it is so obscured by the investing layer of 

 soft parts, as almost to escape notice, till exposed by dissection. Again, 

 the position in the body of the vascular, nervous, and alimentary sys- 

 tems, is completely reversed in the two groups, notwithstanding the 

 close correspondence of many of their details." 



In his second, third, and fourth chapters Dr. Ogilvie has given a very 

 excellent outline of the modifications of the Vertebrate and Articulate 

 types in the several classes of the two great sub-kingdoms. As may 

 be inferred from what we have already said, we think he might with ad- 

 vantage have dwelt on the peculiarities of the Amphibian group, and so 

 in treating of Articulata, our views of their dassiflcation would lead to 

 some changes of plan, thus we can see no more reason for separating the 

 lower Articulata from the higher under a distinct name (they are called 

 Anmdoida by Milne -Edwards,) than for detaching the mites from 

 Arachnida, the Ichthyopthira from Crustacea or any other section of 

 low development from the class which it resembles in the essentials of 

 structure. Annelida with its appended sub-class Entozoa differs from 

 the higher Articulata by just such a change in its external skeleton as 

 is observed in the internal in a few of the lowest Vertebrata. The 

 Rotifera, not mentioned by our author, doubtless from his adopting 

 some different idea of their position, seem to us to constitute the lowest 

 Articulate class ; next to them we place Annelida, of which we must re- 

 gard Entozoa as a mere section containing the less developed forms. 

 The great class Crustacea, so varied and extensive in its series of forms, 

 is the highest in which the functions of vegetative life predominate, 

 whilst Insecta, of which Myriapoda seems to be but an inferior section, 

 and Arachnida complete the sub-kingdom, and specially display the ac- 

 tivity and fierceness which are usually found in those higher classes 

 where the nervous and motory functions are in most vigour. The lead- 

 ing points of contrast between Vertebrata and Articulata are thus sum- 

 med up by our author, pp. 86, 87. 

 « 1. In the skeleton being :— 



In Vertebrata mainly internal ; 



In Articulata wholly external. 



