8 Mr. W. S. Macleay on the Comparative Anatomy 



some day disputed with me ; for when the question was asked, 

 " Is there any thing whereof it may be said, See, this is new?" 

 — the answer was, " It hath been already of old time which was 

 before us." And certain it is, that the doctrines of quinary dis- 

 tribution, of the circular progression of a series of affinity, and 

 of analogies, as distinct from affinities, have all been in some 

 measure advanced by authors prior to the publication of the 

 Hora Entomologies. Indeed it would add little to our convic- 

 tion of these being great natural truths, to find that only one 

 writer had observed them, and that others had taken them for 

 granted upon his assertion. Accordingly we learn, that the 

 number five has had an importance in the construction of the 



for the difference in point of information) would have been similar to that of the "Rhgne 

 Animal distribue apres son Organization;" that is, a description of animals according 

 to a set of groups founded on a difference of structure ; or whether it would have been an 

 arrangement of animals according to their gradual change of structure. The Historia 

 Animalium is conducted on the first plan, not on the last. 



4. Fourthly, Organs may be arranged according to their situation (x«t« tijv dsa-jv) ; as, 

 for instance, animals having pectoral mammae, in opposition to those which have them 

 abdominal. Here again his axiom, that the relation which the whole bears to the 

 whole the part must bear to the part, would fail him, if indeed he intended to apply it ; 

 for two tribes of animals widely asunder from each other, may yet have a similar situa- 

 tion of parts. Yet the variation of position of similar parts is one of the most important 

 considerations in zoology, as may be imagined from its being the very principle upon 

 which the Pkilosophie Anatomique of M. Geoffroy Saint Hilaire is grounded. 



Apt as we are to adopt methods of arrangement, without investigating the principles 

 by which we are guided, we must always reap advantage from examining the mode of 

 reasoning pursued by one who, although among the earliest of naturalists, was so much 

 in the habit of scrutinizing his ideas. He was aware that animals may also be divided 

 according to their scenes of action, their economy, &c. ; and he has, in fact, given us 

 sketches of such classifications : but he had entered too deeply into zoology not to per- 

 ceive that these considerations depend on the structure of their organs. He therefore 

 thought, that the best arrangement ofaninials must depend on that of their organs; — and 

 so far he was right. I only go a little further than he did, in saying, that this arrange- 

 ment ought to depend not on that of the organs, but on their variation of structure. 



universe 



