AFFINITIES AND ANALOGIES OF ORGANIZED BEINGS. 225 



four points, and an analogy to the dragon-fly and Dioncea, 

 from agreeing with them in only three and two points re- 

 spectively. So that an affinity subsists between the bat and 

 dragon-fly, when compared with the Dioncea, and an analogy, 

 when compared with the goatsucker. This seems to me to 

 be a correct statement of Mr. Westwood's views, if I rightly 

 understand them, and they certainly merit the praise of inge- 

 nuity. It seems to me, however, that they contain a fallacy, 

 owing to Mr. W. not having attended to the distinction be- 

 tween essential and non-essential characters. Thus, the 

 words organized, animal, and vertebrate, in the above table, 

 refer to characters of the highest importance to the vital 

 functions of the creature, and consequently, to its place in 

 the natural system, whereas the word fly-catching merely 

 relates to a point of detail in the habits of the creature, of 

 very secondary value, compared to the former characters.* 

 I should say then, that these four creatures have affinities iot 

 one another, in consequence of their agreeing in the essential 

 characters above stated, and that the degree of their affinities 

 is proportionate to the number of the essential points in 

 which they respectively agree, but that their analogies are 

 derived solely from the one non-essential point oi fly -catching, 

 which applies to them all in an equal or nearly equal degree. 

 In short, however strong may be the analogy which the 

 goatsucker bears to the dragon-fly, I do not consider that it 

 has any more affinity to the latter, than it has to a beetle, a 

 lobster, or any other of the Annulosa. 



Since writing the above, I have referred to the very valu- 

 able remarks by Mr. Blyth on affinity and analogy, in ' Mag. 

 Nat. Hist.,' vol. ix. p. 399, &c., to w^hich I had not suffi- 

 ciently attended at the time of their publication. His views 

 appear to me to be more nearly correct than any others which 

 I have seen in print. The chief point in which they differ 

 from mine, is in the introduction of a third term, approxima- 

 tion, as distinct both from affinity and analogy. Mr. Blyth 

 considers it to be a strong resemblance between certain mem- 

 bers of groups really distinct, and he illustrates it by the 

 similitude oiAnthus to Alauda, of Ornithorhynchus to hirds, 

 of Myxine to Mollusca, &c. Now, it seems to me, that this 

 approximation resolves itself into affinity or analogy, accord- 

 ingly as we admit one or other of these two propositions, 

 either that natural groups are quite distinct from each other 



' I only mean that the character oi jiy -catching is unimportant in com- 

 paring groups of such high rank, but of course it becomes an essential 

 character when applied to smaller groups, such as families or genera. 



