36 L UIS A GA SSIZ. 



structure of teeth. Here there is a vast new 

 field to explore. I have already applied it to 

 the identification of the fossil fishes in the 

 Old Red of Russia sent me for that purpose 

 by Mr. Murchison. You will find more ample 

 details about it in my report to him. I con- 

 gratulate myself doubly on the results ; first, 

 because of their great importance in paleon- 

 tology, and also because they will draw more 

 closely my relations with Mr. Owen, whom I 

 always rejoice to meet on the same path with 

 myself, and whom I believe incapable of jeal- 

 ousy in such matters. . . . The only point 

 indeed, on which I think I may have a little 

 friendly difference with him, is concerning the 

 genus Labyrinthodon, which I am firmly re- 

 solved, on proofs that seem to me conclusive, to 

 claim for the class of fishes. 1 As soon as I have 

 time I will write to Mr. Owen, but this need 

 not prevent you from speaking to him on the 

 subject if you have an early opportunity to do 

 so. I am now exclusively occupied with the 

 fossil fishes, which at any cost I wish to finish 

 this winter. . . . Before even returning to 

 my glacier work, I will finish my monograph 

 of the Old Red, so that you may present it at 



1 On seeing Owen's evidence some years later, Agassiz at 

 once acknowledged himself mistaken on this point. 



