RANK OF GROUPS EXEMPLIFIED. 27 I 



and lives only in such situations. Now, if this aquatic 

 division of the sub-genus Parus, instead of merely 

 containing this one bird, comprised twenty or thirty 

 species, we have every reason to conclude, judging from 

 analogy, that it would of itself form a little circle ; and 

 would, consequently, contain a new set of represent- 

 ations of the usual types. But this, as we have 

 already remarked, does not occur in the class of birds ; 

 although it may possibly be found among insects. We 

 therefore terminate our series of circles with the sub- 

 genus Parus proper ; and thus get the following scale 

 of rank in the groups we have progressively passed 

 through. As the same results would attend our search 

 after the station of the common swallow-tailed butterfly 

 (Podalirius Machaon Sw.), we shall give the results of 

 both enquiries together the number being tliree times 

 three, 



PA BUS BIARMICUS. PODALIR1US MACHAON. 



1. Kingdom. Animalia. 1. Kingdom. Animalia. 



2. Sub-kingdom. Vertebrata. 2. Sub-kingdom. Annulosa. 

 3. Class. Aves. 3. Class. Ptilota. 



4. Order. Insessores. 4. Order. Lepidoptera. 



5. Tribe. Dentirostres. 5. Tribe. Diurnes. 



6. Family. Sylviadae. 6. Family. Papilionidffi. 



7. Sub-family. Parianae. 7. Sub-family. Papilionas. 



8. Genus. Parus. 8. Genus. PapUio. 



9. Sub-genus. Venus, proper. 9. Sub-genus. Podalirius. 



(331.) There are several deductions of the highest 

 importance to be made from this table, but at present 

 we must view it only with reference to the value of the 

 groups in the first columns. That these, and these 

 only, so far as the bird in question is concerned, are 

 natural, is, to be inferred from the fact that they are 

 each circular groups, already demonstrated as such by 

 rigorous analysis.* Each circle, according to its supe- 

 rior rank, embraces all those that are beneath it; the test 

 or proofs of the accuracy of each reposing on precisely 

 the same principles. We traverse, in fact, eight circles, 

 one within the other, before we arrive at that which 

 brings us directly to the bird before us. It would, no 



* Northern Zoology, vol. ii. p. 200, &c. 



