8 ON THE SERIES OF NATURE, 



With such a very Hmited knowledge of Zoology as our 

 critic, from what has been said, would seem to possess, I am 

 rather surprised that he should attempt to grapple with ques- 

 tions of the most difficult and abstruse nature; questions, 

 upon which the experience of near thirty years barely enables 

 me, with doubt and difficulty, to venture. Such scruples, 

 however, do not appear in the following new definitions of the 

 various resemblances of animals, as thus given and prefaced 

 by our Reviewer. " When Zoology became a philosophic 

 study, the connexion having been traced between form and 

 function, two elements of scientific classification were admitted : 

 but every casual observer may also detect, in the animal 

 kingdom, the repetition, as it were, of certain organs in crea- 

 tures removed by the other features of their structure far 

 from one another ;" — then the Reviewer quotes my examples, 

 (without acknowledgment,) as if they were facts, brought 

 forward by himself, of analogies. We then have the defi- 

 nitions. " Taking the three terms, Affinity, Analogy, and 

 Resemblance, in the definitions which should belong to them in 

 natural history," our writer defines them in the following 

 words : — 



1. "By affinity, we would understand functional relation, 

 or a similarity of structure, in which a similarity of function or 

 of habit is imphed. 



2. "By analogy, we would express a repetition of similar 

 structures, where the whole of the functions or habits entailed 

 by that structure are not present ; and, 



3. " By resemblance, we would signify a repetition of 

 structure where function is not implied at all." 



To each of these I must call the reader's attention. Defi- 

 nitions are dangerous experiments, and require that every word 

 should be weighed before it is committed to paper. 



1. If, as it is urged, affinity can only be applied to two 

 animals having " a similarity of structure, and a similarity of 

 function or of habit," there are very few affinities in the animal 

 world. For, let us only see how this law would act in practice. 

 By this rule there would be no affinity between the Orang-Otang 

 (Simla satyris, L.), and the Chimpanzee {Troglodytes niger, 

 Geoff.) ; the former has the facial angle 65, and is destitute of 

 superciliary ridges ; the latter has a facial angle of 50, and 

 possesses these ridges : there is not then " a similarity of 



