I 4 6 CHAPTERS ON EVOLUTION. 



want of evidence exists, such deficiency is no fault of ours, but 

 depends on the ' imperfection of the geological record.' But there 

 exists an equally important consideration for our opponents, in the 

 fact that the very circumstances under which new species are produced 

 may frequently obviate the necessity for the existence of missing links 

 and transitional forms. This latter contention can be supported by 

 the plainest evidence, and on this preliminary point namely, the 

 reason for the justifiable and natural absence of transitional forms 

 we may firstly lead evidence." 



Is it necessary, then, that we should, by the laws of, and in the 

 very nature of the origin of species by, evolution, or by Mr. Darwin's 

 principle of " natural selection," always expect to find transitional 

 forms connecting existing species ? Mr. Darwin's reply to this question 

 is a negative. The new varieties or species which appear will tend, 

 by the very conditions of evolution, to present improvements on the 

 species which preceded them; and, on the principle that " the weakest 

 go to the wall," the ancestors of existing species will in many cases have 

 become exterminated by their successors being better adapted than 

 themselves to survive in the " struggle for existence." The parent- 

 species will fail in the competition involved in the struggle with its 

 offspring. Viewing each species as usually the product of an improved 

 constitution, we may naturally expect the parent-form and the tran- 

 sitional links to have become exterminated, as Mr. Darwin remarks, 

 " by the very process of the formation and perfection of the new 

 form." But extinct animals are liable to be preserved as " fossils " 

 in the rocks composing the crust of the earth, and yet "missing 

 links " are not discoverable in any adequate proportions. This latter 

 fact has already been mentioned, and the reason assigned in the 

 fragmentary condition of nature's great geological museum. Neglecting 

 the geological evidence for the nonce, it might still be contended that 

 living species as noted by us to-day should be more closely con- 

 nected than they are, were their creation by evolution and descent a 

 probable theory. 



Now, the pith of the evolutionist's reply consists in showing that 

 such connecting species or forms are by no means to be expected as 

 a matter of course, and that their absence is, in fact, actually favour- 

 able to his views and opinions. Consider a well-known and proved 

 case of the origin of very different varieties from a common stock, 

 that of the Pigeons. The various breeds or races of pigeons, of which 

 the four best known are the pouters, fantails, carriers, and tumblers, 

 may be certainly regarded as having descended from the Rock Pigeon 

 (Columba livia}. Between the various breeds of pigeons, the differences 

 are so marked as to be of " specific " character. Their variations are 

 so plain and distinct, that had these birds been met with in a wild 

 state and been examined by ornithologists, they would have been 



