584 LOUIS AGASSIZ. 



skulls in such a way that their origin cannot 

 be mistaken. Beside this, every possible effort 

 should be made to obtain perfect heads, pre- 

 served in alcohol, so that all their features may 

 be studied minutely and compared. Where 

 this cannot be done portraits or photographs 

 may be substituted. 



Trusting that you may help me in this way 

 to bring together in Cambridge a more com- 

 plete collection, illustrative of the natural his- 

 tory of mankind than exists thus far any- 

 where, 1 



I remain, ever truly your friend and brother, 



Louis AGASSIZ. 



The following letter to Mr. Ticknor is in 

 the same spirit as previous ones to Mr. Halde- 

 man and others, concerning the distribution 

 of fishes in America. It is given at the risk 

 of some repetition, because it illustrates Agas- 

 siz's favorite idea that a key to the original 

 combination of faunae in any given system 

 of fresh waters, might be reached through a 

 closer study than has yet been possible of the 

 geographical or local circumscription of their 

 inhabitants. 



1 All the ethnographical collections of the Museum of Com- 

 parative Zoology have now been transferred to the Peabodj 

 Museum, where they more properly belong. 



