108 AMERICAN FISHES. 



those on the vomer consisting of a circular cluster on the knob of that 

 bone, and of a double row extending at least half an inch backward. 



The dorsal fin is situated in the middle of the fish, and contains 

 fourteen rays, the eighth ray being exactly central between the snout 

 and the tip of the central caudal fin-ray. The second adipose dor- 

 sal fin is small and obtusely formed. The caudal fin has nineteen, 

 the ventrals each nine, the anal eleven, and the pectorals each four- 

 teen rays. The origin of the ventral fins is slightly posterior to the 

 centre of the fish. 



Such are the principal structural distinctions of this noble fish, and 

 1 have entered into these rather at length, since by them only can he 

 be distinguished from his lake congeners. I have already observed the 

 great differences existing in point of color and markings between fish 

 of the same species found in different waters, throughout this family, 

 and endeavored to show the impropriety of founding specific distinc- 

 tions, or even permanent varieties, by reference to these alone, without 

 reference to structure. In the Salmo Fontinalis, common Brook 

 Trout, this is easy to be noticed, but in none of the Salmonida with 

 which I am acquainted are the differences of color and marking so 

 broad and distinct as in different individuals of this species. I have 

 before me, as I write, three colored representations of this same fish, 

 two water-color sketches, by Mr. Cabot, of Boston, and one, a colored 

 lithograph, in Dr. Richardson's Fauna Boreali- Americana ; and thes? 

 three I am certain would be pronounced by nine persons out of ten 

 not accustomed to observe structural differences, three different fish. 

 Indeed, I am informed by Prof. Agassiz, that by the French residents 

 on lakes Huron and Superior, they are actually believed to be three 

 distinct fish, and are known by three different names, from the locali- 

 ties in which they are found, viz. : Truite des Battures, Trout of the 

 rocky .shallows Truite de G-reve, Trout of the muddy shoals and 

 Truite du Large, Trout of the deep open waters. The first of these 

 fish is represented in the large plate facing this paper, and the second 

 in the cut at the head of page 104. The third is thus described in Dr. 

 Richardson's work named above : " The head, back and sides have 

 a dark greenish gray color, which when examined closely is resolved 

 into small roundish yellowish gray spots on a bluish gray ground, 

 which covers less space than the spots ; the latter are most evident oil 



