41 CLASSIFICATION. 



Nevertheless, their genealogical arrangement remains strictly 

 true, not only at the present time, but at each successive 

 period of descent. All the modified descendants from A will 

 have inherited something in common from their common 

 parent, as will all the descendants from I ; so will it be vith 

 each subordinate branch of descendants at each successive 

 stage. If, however, we suppose any descendant of A or of I to 

 have become so much modified as to have lost all traces of its 

 parentage in this case, its place in the natural system will be 

 lost, as seems to have occurred with some few existing organ 

 isms. All the descendants of the genus F, along it ^vhole 

 line of descent, are supposed to have been but little modified, 

 and they form a single genus. But this genus, though much 

 isolated, will still occupy its proper intermediate position. 

 The representation of the groups, as here given in the dia- 

 gram on a flat surface, is much too simple. The branches 

 ought to have diverged in all directions. If the names of 

 the groups had been simply written down in a linear series, 

 the representation would have been still less natural ; and it 

 is notoriously not possible to represent in a series, on a flat 

 surface, the affinities which we discover in nature among the. 

 beings of the same group. Thus, the natural system is gene- 

 alogical in its arrangement, like a pedigree. But the amount 

 of modification which the different groups have undergone 

 has to be expressed by ranking them under different so- 

 called genera, sub-families, families, sections, orders, and 

 classes. 



It may be worth while to illustrate this view of classifi- 

 cation, by taking the case of languages. If we possessed 

 a perfect pedigree of mankind, a genealogical arrangement 

 of the races of man would afford the best classification of 

 the various languages now spoken throughout the world ; 

 and if all extinct languages, and all intermediate and slowly 

 changing dialects, were to be included, such an arrangement 

 would be the only possible one. Yet it might be that some 

 ancient languages had altered very little and had given rise 

 to few new languages, while others had altered much, owing 

 to the. spreading, isolation, and state of civilization of the 

 several co-descended -races, and had thus given rise to many 

 new dialects and languages. The various degrees of differ- 

 ence, between the languages of the same stock would have 

 to. be expressed by : -groups :Subordinate to groups; but the 

 proper, or even. the- only. possible arrangement would still be 

 genealogical; and this would be strictly natural, as- it wouldi 



