CiiAP. ir. BRANCHES OF THE AXIMxVL KINGDOM. 139 



of Ai'istotle, Lamarck, OktMi, and Ehrenberg together, have we not, as characteristic 

 of their systems, the very words by which ever}' one distinguishes the most promi- 

 nent features of the body of the higher animals, when speaking of blood relations, 

 of blood and bones, or of having flesh and nerve ? 



Neither of these observers has probably been conscious of the identity of his 

 classification with that of his predecessors ; nor, indeed, should we consider either 

 of them as superfluous, inasmuch as it makes prominent, features more or less differ- 

 ent from those insisted vipon by the others; nor ought any one to suppose that 

 with all of them the field is exhausted, and that there is no more room for new 

 systems upon that very first distinction among animals.^ As long as men inquire 

 they will have opportunities to know more upon these topics than those who have 

 gone before them, so inexhaustibly rich is nature in the innermost diversity of her 

 treasures of beauty, order, and intelligence. 



So, instead of chscarding all the systems which have thus far had little or no 

 influence upon the jirogress of science, either because they are based upon prin- 

 ciples not generally acknowledged or considered worthy of confidence, I have care- 

 fully studied them with the A'iew of ascertaining whatever there may be true in 

 them, from the stand-point from which their authors have considered the animal 

 kingdom ; and I own that I have often derived more information from such a careful 

 consideration than I had at first expected. 



It was not indeed by a lucky hit, nor by one of those unexpected apparitions 

 which, like a revelation, suddenly break upon us and render at once clear and 

 comprehensible what had been dark and almost inaccessible before, that I came to 

 undei-stand the meaning of those divisions called types, classes, orders, families, gen- 

 era, and species, so long admitted in Natural History as the basis of every system, 

 and yet so generally considered as mere artificial devices to facilitate our studies. 

 For years I had been laboring under the impression that they are founded in 

 nature, before I succeeded in finding out upon what principle they were really based. 

 I soon perceived, however, that the greatest obstacle in the way of ascertaining 

 their true significance lay in the discrepancies among diflerent authors in their use 

 and application of these terms. Different naturalists do not call by the same name 

 groups of the same kind and the same extent: some call genera what others call 

 subgenera ; others call tribes, or even families, Avhat are called genera by others ; 



* By way of an example, I would mention the ditfi-rent from what is observed in any of tlie Inver- 



mode of reproduetion. The formation of the epg in tebrata, that the animal kingdom, elassilied according 



Vertebrata; its orijjin, in all of tlicin, in a more or to these facts, would again be divided into two great 



less complicated Gnuifian vesicle, in which it is groups, corresponding to the Vertebrata and Iiirerte- 



nursed ; the formation and development of the embryo bratn of Lamarck, or the Fles/i- and Gut-Animals of 



up to a certain period, etc., etc., are so completely Oken. or the Eneima and Aiiriina of Aristotle, etc. 



