ON AFFINITY AND ANALOGY. 143 



others," constituting its relations of affinity and analogy. It 

 is in consequence of the more complete resemblance in the 

 numerical majority of the essential characters of the two 

 beings or groups of beings contrasted together, that the rela- 

 tionship becomes one of affinity ; while from a resemblance 

 in the numerical minority of such essential characters, the 

 relationship is deemed an analogy. 



In proceeding with our examination of the principle above 

 stated, it will be necessary that in addition to the swallow, 

 the goat-sucker, and the bat, we extend our views to the mar- 

 tin, the swift, and the dragon-fly; all which are distinguished 

 by their large wings when extended in action, their rapid 

 motions, large mouths, and insectivorous hawking flight. 



The swallow and the martin are two birds belonging to the 

 same genus (Hirimdo), and resembling each other in the 

 greatest possible number of their essential characters ; they 

 are therefore allied together by an affinity of the first or high- 

 est degree. Between these birds and the swift, a bird be- 

 longing to a different genus but to the same family, we find 

 an affinity of a lower, or second degree. A third or still low- 

 er, is found between the goat-sucker, belonging to a different 

 tribe, and the three preceding birds. Again, as vertebrated 

 animals, the bat and the four birds above mentioned exhibit 

 an affinity when compared with animals belonging to the four 

 invertebrated sub-kingdoms, whilst as members of the animal 

 kingdom, and compared with members of the vegetable king- 

 dom, the dragon-fly (an invertebrated animal) and the five 

 vertebrated animals above alluded to, are related together by 

 affinity. 



It may however, and probably will be, said, that in the case 

 of the two last-mentioned animals (thebat belonging to the Ver- 

 tebrata, and the dragon-fly to the Annulosa), I am confound- 

 ing analogy with affinity. I however maintain the contrary 

 to be the case, asserting that these relations are strictly com- 

 parative and relative; that if the relation between the swallow 

 and the martin, as species respectively possessing the charac- 

 ters of the next higher group (that is, genus), when compared 

 with the swdft or any other bird belonging to the other groups 

 of the next higher rank be deemed an affinity ; or if the rela- 

 tion between the swallow and the goat-sucker, founded upon 

 a comparison of their joint characters as belonging to the 

 higher group {Aves)^ when compared with the animals com- 

 posing the other vertebrated orders (the bat for example) be 

 deemed an affinity; the relation between the bat and the 

 goat-sucker, as vertebrated animals, when compared with all 

 invertebrated animals (the dragon-fly for instance) must also 



