CHAP. XI.J ANCIENT AND LIVING FORMS. 289 



competition with the existing inhabitants, the former would be 

 beaten and exterminated by the latter, as would the secondary 

 by the eocene, and the paheozoic by the secondary forms. So that 

 by this fundamental test of victory in the battle for life, as well 

 as by the standard of the specialisation of organs, modern forms 

 ought, on the theory of natural selection, to stand higher than 

 ancient forms. Is this the case? A large majority of palaeon- 

 tologists would answer in the affimative ; and it seems that this 

 answer must be admitted as true, though difficult of proof. 



It is no valid objection to this conclusion, that certain Brachio- 

 pods have been but slightly modified from an extremely remote 

 geological epoch ; and that certain land and fresh- water shells 

 have remained nearly the same, from the time when, as far as is 

 known, they first appeared. It is not an insuperable difficulty 

 that Foraminifera have not, as insisted on by Dr. Carpenter, pro- 

 gressed in organisation since even the Lauren tian epoch ; for some 

 organisms would have to remain fitted for simple conditions of 

 life, and what could be better fitted for this end than these lowly 

 organised Protozoa ? Such objections as the above would be fatal 

 to my view, if it included advance in organisation as a necessary 

 contingent. They would likewise be fatal, if the above Fora- 

 minifera, for instance, could be proved to have first come into 

 existence during the Laurentian epoch, or the above Brachiopods 

 during the Cambrian formation ; for in this case, there would not 

 have been time sufficient for the development of these organisms 

 up to the standard which they had then reached. When advanced 

 up to any given point, there is no necessity, on the theory of 

 natural selection, for their further continued progress; though 

 they will, during each successive age, have to be slightly modified, 

 so as to hold their places in relation to slight changes in their 

 conditions. The foregoing objections hinge on the question 

 whether we really know how old the world is, and at what period 

 the various forms of life first appeared; and this may well be 

 disputed. 



The problem whether organisation on the whole has advanced 

 is in many ways excessively intricate. The geological record, at 

 all times imperfect, does not extend far enough back, to shew 

 with unmistakeable clearness that within the known history of 

 the world organisation has largely advanced. Even at the present 

 day, looking to members of the same class, naturalists are not 

 unanimous which forms ought to be ranked as highest : thus, 

 some look at the selaceans or sharks, from their approach in 

 some important points of structure to reptiles, as the highest fish ; 

 others look at the teleosteans as the highest. The ganoids stand 

 intermediate between the selaceans and teleosteans ; the latter at 

 the present day are largely preponderant in number; but fromerly 



