308 State of Development of Chap, xl 



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, progressed in organisation since 

 even the Laurentian 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 Foraminifera, for instance, could be 

 proved to have first come into existence during the Laurentiaft 

 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 show 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 formerly selaceans and 

 ganoids alone existed ; and in this case, according to the standard 

 of highness chosen, so will it be said that fishes have advanced or 

 retrograded in organisation. To attempt to compare members of 

 distinct types in the scale of highness seems hopeless ; who will 

 decide whether a cuttle-fish be higher than a bee— that insect which 

 the great Yon Baer believed to be " in fact more highly organised 

 than a fish, although upon another type " ? In the complex struggle 

 for life it is quite credible that crustaceans, not very high in their 



