SUMMARY OF ' PHILOSOPHIE ZOOLOGIQUE.' 26$ 



" Simplicity is the main end of any classification. If 

 all the races, or as they are called, species, of any 

 kingdom were perfectly known, and if the true analogies 

 between each species, and between the groups which 

 species form, were also known, so that their approxi- 

 mations to each other and the position of the several 

 groups were in conformity with the natural analogies 

 between them — then classes, orders, sections, and 

 genera would be families, larger or smaller; for each 

 division would be a greater or smaller section of a 

 natural order or sequence.* But in this case it would 

 be very difficult to assign the limits of each division ; 

 they would be continually subjected to arbitrary alter- 

 ation, and agreement would only exist where plain and 

 palpable gaps were manifest in our series. Happily, 

 however, for classifiers there are, and will always pro- 

 bably remain, a number of unknown forms." t 



That the foregoing is still felt to be true by those who 

 accept evolution, may be seen from the following pas- 

 sage, taken from Mr. Darwin's ' Origin of Species ' : — 



"As all the organic beings which have ever lived 

 can be arranged within a few great classes ; and as all 

 within each cleiss have, according to our theory, been 

 connected together by fine gradations, the best, and if 

 our collections were nearly perfect, the only possible 

 arrangement would be genealogical : descent being the 

 hidden bond of connection which naturalists have been 

 seeking under the term of the Natural System. On 

 this view, we can understand how it is that in the eyes 

 of most naturalists, the structure of the embryo is 

 » 'Phil. Zool.,' torn. i. p. 50. f Pages 50, 51. 



