388 | THE ZOOLOGIST. 
now practically extinct from so many areas, their former presence 
is proved by the hard-wooded and spinous trees and shrubs which 
have almost alone survived. And thus natural selection has 
acted on the original flora and fauna in which this obscurely 
understood evolutionary response to environmental conditions 
played such a vast and primary part. Natural selection is not 
the act of creation, but the effect of competition; it guides the 
battles, and directs the forces it did not provide. There seems 
indeed some prospect of ‘‘ natural selection”’ being relegated by 
some writers to the old armoury of teleology. Thus a recent 
writer has remarked that it is held by ‘“‘ Wallace and others 
among our deeper-thinking naturalists, that the workings of 
natural selection are incomprehensible unless we regard them as 
suided by a controlling intelligence.”* A much more weighty 
argument is “that the conception of the struggle for existence 
has derived its force, not wholly from actual observation of what 
occurs, but very largely from inference as to what, it is believed, 
must occur.’’t 
We may, however, quit these realms of suggestion, and 
observe how even in our scanty geological records we see ex- 
hibited some phases of the commencement of a struggle for 
existence. Thus, after a period of animal evolution which may 
be computed by millions of years, and in which fish abounded, 
perhaps not yet altogether under a severe stress of selection and 
survival, the Mesozoic period arrives, when, in the words of 
Oscar Schmidt, ‘‘the Placoids and Ganoids, hitherto predomi- 
nating in the ocean almost without a foe, now found over- 
whelming enemies in the true Sea-lizards or Enaliosaurians, 
especially the Ichthyosaura and Plesiosaura.’{ Here we see 
natural selection, with its iron and implacable rule, a real factor 
there must be a corresponding diminution of transpiration, and the tree is 
enabled to preserve its sap when, during the dry season, its roots cannot 
any longer obtain a supply of moisture” (‘Across East African Glaciers,’ 
p. 68). 
* Kirby, ‘ Nature,’ vol. lili. p. 77. 
+ Thomson, ‘ Natural Science,’ vol. viii. p. 22. The Right Hon. A. J. 
ce hel i 
Balfour has now invoked—perhaps sarcastically—the aid of ‘natural “ 
selection” to account for such a theological conception as “free will” 
(‘ Foundations of Belief,’ p. 20). 
{ ‘ Doctrine of Descent,’ p. 74. 
