CHAP. xxn. OBJECTIONS TO TRANSMUTATION. 425 



species and genera, instead of such strong lines of demarca- 

 tion, and often wide intervening gaps ? 



We may consider this objection under two heads : — 



First, To what extent are the gradational links really 

 wanting in the living creation or in the fossil world, and 

 how far may we expect to discover such as are missing by 

 future research ? 



Secondly, Are the gaps more numerous than we ought to 

 anticipate, allowing for the original defective state of the 

 geological records, their subsequent dilapidation, and our 

 slight acquaintance with such parts of them as are extant, 

 and allowing also for the rate of extinction of races and 

 species now going on, and which has being going on since 

 the commencement of the tertiary period? 



First, As to the alleged absence of intermediate varieties 

 connecting one species with another, every zoologist and 

 botanist who has engaged in the task of classification has 

 been occasionally thrown into this dilemma: — if I make 

 more than one species in this group, I must, to be con- 

 sistent, make a great many. Even in a limited region like 

 the British Isles this embarrassment is continually felt. 



Scarcely any two botanists, for example, can agree as to 

 the number of roses, still less as to how many species of 

 bramble we possess. Of the latter genus, Ruhus, there is 

 one set of forms, respecting which it is still a question 

 whether it ought to be regarded as constituting three species 

 or thirty-seven. Mr. Bentham adopts the first alternative, 

 and Mr. Babington the second, in their well-known treatises 

 on British plants. 



We learn from Dr. Hooker's Flora of Australia, that this 

 same genus Bubus abounds likewise at the antipodes, and is 

 there also rich in variable species. When we consider how, 

 as we extend our knowledge of the same plant over a wider 

 area, new geographical varieties commonly present them- 



