TYPICAL GROUPS OF THE ANNULOSA. 11 



show a mutual relationship between these two great 

 divisions of animals hitherto undiscovered. 



(10.) Before taking leave of these analogies, it will be 

 as well to make a few additional observations relative to 

 the two typical groups. As we wish to meet difficulties 

 rather than to avoid them, we may here anticipate an 

 objection that may be urged against the theory of the 

 Ptilota being the pre-eminently typical group of the An- 

 nulosa. If, it may be argued, the annular rings of which 

 their body is composed be the chief characteristic of in- 

 sects, then it would reasonably follow, that those which 

 have the greatest number of these rings are the most ty- 

 pical. The consequence of this admission would be, that 

 the Apterafa the head of which stands thelulidce') would 

 become the most typical Annulosa. This theory appears 

 to receive additional support from the fact that the Ap- 

 tera in our table stand in a parallel line of analogy to the 

 quadrupeds, which, in many other respects, they certainly 

 represent. The Ptilota, or winged insects, having fewer 

 segments to their body, thus become the sub-typical 

 group, holding the same rank among Annulosa as birds 

 do among Vertebrata. These arguments, which are cer- 

 tainly entitled to much consideration, for a long time ex- 

 cited strong doubts in our mind as to which of these we 

 should apply the term typical. On the other hand, if 

 we embrace the received opinion that metamorphosis is 

 the great characteristic of these animals, then the dif- 

 ficulty is solved, since this peculiarity is only seen in its 

 full development among the Ptilota, which would thus 

 become pre-eminently typical. Besides, in all the groups 

 of the animal kingdom which we have investigated, and 

 our readers are now aware that the number is not small, 

 we have invariably found that the most perfect ani- 

 mals, that is, those whose organisation or instincts were 

 most superior, were invariably the typical. In this way 

 Vertebrata are superior to Annulosa, quadrupeds to birds, 

 the Quadrumana and the Insessores to the Ferce and the 

 Raptores, and so on. When, therefore, we find this 



