REVIEW OF FOSSIL FISHES. 241 



procession of living beings, as he was wont 

 to do, in their gradual introduction upon the 

 earth. Indeed, his whole future work in ich- 

 thyology, and one might almost say in gen- 

 eral zoology, was here sketched. 



The technicalities of this work, at once 

 so comprehensive in its combinations and so 

 minute in its details, could interest only the 

 professional reader, but its generalizations 

 may well have a certain attraction for every 

 thoughtful mind. It treats of the relations, 

 anatomical, zoological,. and geological, between 

 the whole class of fishes, fossil and living, il- 

 lustrated by numerous plates, while additional 

 light is thrown on the whole by the revelations 

 of embryology. 



" Notwithstanding these striking differ- 

 ences," says the author in the opening of the 

 fifth chapter on the relations of fishes in gen- 

 eral, " it is none the less evident to the atten- 

 tive observer that one single idea has presided 

 over the development of the whole class, and 

 that all the deviations lead back to a primary 

 plan, so that even if the thread seem broken 

 in the present creation, one can reunite it on 

 reaching the domain of fossil ichthyology." ^ 



Having shown how the present creation has 



1 Vol. i. chapter v. pp.- 92, 93. 

 TOL. I. 16 



