206 ON SYSTEMATIC ZOOLOGY. 



only, which are lout five : <e Indeed, when it is consi- 

 dered that there were so many affinities to be reconciled 

 with this constant use of the number five, it is clearly 

 absurd to imagine that I would have hampered myself 

 needlessly with such a rule. My sole object has been 

 to demonstrate natural affinities ; and in doing this I 

 have fallen on a distribution into five groups, so uni- 

 formly, that where there seems to be an exception to 

 the rule, it appears to be as much the consequence of 

 our little acquaintance with the manifold productions of 

 nature, as of any other cause whatsoever. No person, 

 however, can be more reluctant than I am to make 

 any conclusion on this subject precipitately ; and, there- 

 fore, in saying that there is a general tendency, in every 

 natural group of animals, to be subdivided into five 

 others, I would only have this opinion accounted an 

 hypothesis, which is riot entirely destitute of arguments 

 wherewith we may support its truth. Yet I must ac- 

 knowledge that it appears to me, even by what we have 

 already seen, to be so far established, that, in future, 

 where great chasms occur in smaller groups, I shall con- 

 sider myself entitled to suppose that these proceed from 

 our ignorance of the productions of nature."* Upon 

 the whole, therefore, we are justified in concluding that 

 our author believes some groups to be composed of ten 

 circles, and others of five, or, what is the same thing, 

 that sometimes there are five large groups and five 

 smaller ones, and sometimes five only. 



(26l.) We now come to the fourth principle of 

 natural arrangement, pointed out by our author, viz., 

 that here is a tendency in such groups as are placed at 

 the opposite points of a natural circle to unite. But on 

 this intricate subject we wMl take his own words, and 

 his own illustrations of their meaning. For this pur- 

 pose let the reader refer to the diagram of the animal 

 kingdom, as to a map, while he peruses attentively the 

 following passage : "On the examination of this 



* Hor. Ent p. 822. 



