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and last group is a small assemblage of species now confined 

 to Ireland and the extreme south-west of England, and all may 

 be regarded as regressive species. 



This distribution is quite or sufficiently similar to that of 

 the mollusca to be satisfactorily explained in the same way. 



Even in Botanical science, although a connected scheme 

 of the distribution of life has never been constructed or demon- 

 strated, yet it is clear from evidence that can doubtless be 

 adduced that in the opinion of eminent botanists exactlv the 

 same principles are in operation as I have demonstrated to 

 exist in animal life. 



Mr. Bentham describes the plants of the European region 

 as endowed with great powers of dispersal, very prolific, and 

 capable of adapting themselves to a great variety of climatological 

 and physical conditions, with a continuity of distribution that 

 bespeaks a comparatively modern origin. I do not dwell on the 

 opinions of Mr. Bentham as to their history (PI. X, fig. 10). 



In corroboration of Mr. Bentham's views as to the undoubted 

 dominancy of European plants, we have the declaration of 

 Sir Joseph Hooker that the European flora, being, as pointed 

 out by Bentham, of a dominant character, is propagated as a 

 wave of life from Europe to the uttermost ends of the earth, 

 and judging from the number of species cited as existing in a 

 number of places throughout the world, these waves of life 

 would follow the routes along which other organisms travel 

 and have travelled. 



The struggle for existence is also as deadly and efficient 

 in plants as in animals, for, as Prof. Henslow justly remarks, 

 plants hold their position as long as other more advanced com- 

 petitors will let them grow. He instances the little Dutch clover, 

 which in New Zealand is driving the huge New Zealand flax 

 before it. 



It is also well known that floras now indigenous to Japan 

 or the Himalayas, to Australia and South America, once in- 

 habited Europe, and that groups of wholly different plants 

 successively displace each other, demonstrating that, as with 

 animal life, there is a slow, unceasing migration constantly 

 going on. 



In Man we have also a full confirmation of exactly the same 

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