M. Agassiz on Fossil Fishes. 343 



found in the secondary epoch ; for if it is the task of a system 

 to assign a reason for all the phenomena which it embraces, 

 it is evident that precursors of the kind alluded to, such as the 

 Didelphis of Stonesfield and the birds of Glaris, offer difficul- 

 ties of no easy solution. 



At the top of the scale of the vertebrata, our author places 

 man as the crown of the creation, and whom he regards as 

 the object and end of the creation. According to M. Agassiz, 

 it is with reference to man that this successive and continuous 

 development, from fishes to reptiles, from reptiles to birds and 

 the mammifera, and from the latter to man himself, has been 

 effected. But this process of perfection has not been effected 

 by filiation — ^by direct procreation, since all the species are 

 different as we go from one formation to another. The bond 

 which unites them is not a material bond ; it exists in the 

 mind of the Creator, who had in view an intelligent being 

 whom he designed to be sovereign over all. M. Agassiz thus 

 expresses his thoughts on this subject : — " The progressive 

 connection, as if by the links of a chain, of the four classes of 

 vertebrate animals, is a fact which contrasts, in every respect, 

 and in a very striking manner, with the uniform and parallel 

 development of all the classes of the invertebrata. The gi-a- 

 dation of the vertebrates is so much the more remarkable, on 

 accoimt of its direct connection with the advent of man, whom 

 we may consider not only as the term, but also as the object 

 of all this development. Let us first regard fishes, which ap- 

 peared first. Plunged in a medium denser and less mobile 

 than the atmosphere, they are always found in conditions of 

 existence less varied than those of terrestrial animals. Their 

 body is all of a piece ; their head is not detached from the 

 trunk, of which it is nothing else than a simple prolongation ; 

 their organs are obtuse, and their faculties very limited ; their 

 members placed in pairs are not the principal organs of 

 motion, and there exist only very slight relations between 

 individuals of the same species. Reptiles, which succeed 

 fishes in the order of time, present us with a more perfect 

 organization ; their head is more or less detached from the 

 rest of the body, and can even be raised above the horizontal 

 line which the trunk still forms ; the members in pairs, when 



