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October 4, 1848. 

 The President in the Chair. 



Present nineteen members. 



The business of the meeting was opened by Prof. 

 Agassiz, who announced that during a recent visit to Lake 

 Superior, he had made a special study of its fishes. Among 

 them he had found several new species, and even new 

 genera ; and one fish, with a head like a perch, and a se- 

 cond dorsal fin, adipose, concerning which he was in doubt 

 in what family to place it. He proposed, on the present 

 occasion, to confine his remarks to the SalmonidcB. Prof. 

 A. then gave a general sketch of the classification of the Sal- 

 monidcE, now in use, and passed on to some observations 

 on some of the Lake Superior species. One of them he 

 believed to be identical with Salmo fontinalis, the com- 

 mon Brook Trout of the streams of other parts of the 

 United States. 



Salmo amethystus, Namacusli. Of this species Prof. A. 

 remarked, that the color to which it owes its name does not show 

 itself distinctly while the fish is swimming, or when first caught; 

 but only after being taken from the water, when the mucus on 

 the surface begins to dry. The general color of this species 

 varies with the ground on which it is caught. Those found on 

 a muddy bottom are generally greyish, while those from a grav- 

 elly bottom are of a reddish color, with much brighter fins. The 

 sexes differ in shape, the male having a more pointed head than 

 the female, although the jaws are of equal length. The ventral 

 fins are placed very far lack ; a valuable specific mark in the 

 SalmonidcB^ a family in which it is very difficult to fix on charac- 

 teristic differences. The S. amethystus is the most valuable fish 

 for food found in Lake Superior. In answer to a question from 

 Dr. Storer, Prof. A. replied that he did not notice the amethystine 

 color in the mouth of this species. 



Salmo siskiwit, Ag. This also is a fish of high flavor, but 



