554 Classification of Animals. 



3. The contents of such a circular group are symbolically (or 

 analogically) represented by the contents of all other circles in the 

 animal kingdom. 



4. That these primary divisions of every group are characte- 

 rized by definite peculiarities of form, structure, and economy, 

 which, under diversified modifications, are uniform throughout the 

 animal kingdom, and are therefore to be regarded as the primary 

 types of nature. 



5. That the different ranks or degrees of circular groups ex- 

 hibited in the animal kingdom are nine in number, each being in- 

 volved within the other. 



These he proceeds to establish by interesting details, and which, 

 so far as we have had an opportunity of examining, tend to sub- 

 stantiate their truth and universality as general laws. In regard 

 to the first, it is almost unnecessary to say we have long considered 

 it as fully established, not only by the arguments advanced by its 

 discoverer, but by the subsequent severe analytical examination it 

 has undergone. As to the second proposition, it is, we believe, likely 

 to prove correct, being in accordance with the first division of na- 

 tural bodies, animals, vegetables, and minerals, but we think a fur- 

 ther investigation, particularly of the lower tribes of animals, is re- 

 quired, before it can be fully established as a general law. Should, 

 however, the three divisions of the aberrant group be found inva- 

 riably to form a circle of their own, then we must consider them 

 only as one, though always divisible, or made up of three secondary 

 circles, representing the Rasorial, Grallatorial, and Natatorial 

 types ; this law, however, of an actual trinary, instead of a quinary 

 disposition, does not affect the natural series by which they are 

 united ; for, as Mr Swainson justly observes, " the discovery of 

 the union of Mr M'Leay's three aberrant groups into a circle of 

 their own is the addition only of a new property superadded to 

 that which they were known to possess, this property consisting of 

 uniting into a circle of themselves, as well as passing into the typi- 

 cal and subtypical groups." The third proposition, on the law of 

 representation, which there is every reason to believe is of universal 

 and not of partial application, is ably treated, and only requires to 

 be further tested and investigated in the lower departments of 

 zoology, to be admitted as another general law. In the suc- 

 ceeding chapter he enters into a detailed exposition of the fourth 

 proposition, in which the primary types are pointed out. The 

 fifth and last proposition is rested upon facts and observations, 



