Recherches sur les Poissons Fossiles. 



79 



the latter Homocerous Lepidoides. It is a very remarkable 

 circumstance in regard to the genera of which these two sec- 

 tions consist, that all the species with oblique caudal hitherto 

 discovered, without exception, are found in strata anterior to 

 the lias, a circumstance 'that cannot be accidental ; for we see 

 the same peculiarity displayed in an almost equal number of 

 species of the same period, belonging to another order of fossil 

 fishes, Saurides, as well as in all the fossil fishes of the order 

 Placoides, by which the Ganoids and Sauroids are accom- 

 panied in the same strata. So that some unknown condition 

 of existence in those remote times," says M. Agassiz, " would 

 appear to have exercised its influence on the development of 

 organic life, to determine a conformation so singular, and 

 yet so general, throughout this class of animals." We have 

 ourselves, in the preceding remarks, offered our own views on 

 the subject. It is only necessary to repeat, that we see the 

 structure of animals everywhere corresponding with their 

 functions, while these are adapted to the various relations 

 of surrounding objects. It is therefore a legitimate conclu- 

 sion to draw, that as the remains of these fossil fishes are 

 distinguished by the same peculiar form of the spinal column 

 as the cartilaginous fishes of the present day, they like- 

 wise inhabited deep water, whether salt or fresh, and were 

 highly rapacious in their habits. 



The latter part of the conclusion at least corresponds with 

 that to which M. Agassiz himself has been led, but we are 

 not yet prepared to agree with M. Agassiz, as to the evi- 

 dence afforded by fossils in general, or by fossil fishes in 

 particular, of the progressive development of organic life, 

 from a simple, to a more complex and perfect structure. This 

 view has been frequently suggested, and as often refuted, 

 and we thought it had been finally abandoned for the last 

 thirty years. The peculiar development of the caudal ver- 

 tebrae in these ancient fossils, presents to our view no indica- 

 tion of a less degree of perfection, than the abrupt termination 



