64 SALMONIA. [SECOND DAY. 



small fish of both, these varieties, which were as 

 marked as possible in their characters, one silvery, 

 like a young salmon, blue on the back, and with 

 small black spots only, the other, with yellow belly 

 and red spots, and an olive-coloured back. 1 have 

 made similar observations in other lakes, particularly 

 in that of the Traun near Gmiinden, and likewise at 

 Loch Neah in Ireland. Indeed, considering the sea 

 trout as the type of the species trout, I think all the 

 other true trouts may not improperly be considered as 

 varieties, in which the differences of food and of habits 

 have occasioned, in a long course of ages, differences 

 of shape and colours, transmitted to offspring in the 

 same manner as in the variety of dogs, which may 

 all be referred to one primitive type.* 



* I have known the number of spines in the pectoral fins different, 

 in different varieties of trout; I have seen them 12, 13, and 14 : but 

 the anal fin always, I believe, contains 11 spines, the dorsal 12 or 

 13, the ventral 9, and the caudal 21. The smallest brook trout, 

 when well and copiously fed, will increase in stews to four or five 

 pounds in weight, but never attains the size or characters of lake 

 trout. 



Mr. Tonkin of Polgaron put some small river trout, 2^ inches in 

 length, into a newly-made pond. He took some of these out the 

 second year, and they were above 12 inches in length ; the third year, 

 he took one out that was 16 inches; and the fourth year, one of 25 

 inches: this was in 1734. (Carew's Survey of Cornwall, p. 87. 

 Lord de Dunstanville's edition.) 



[It is now generally admitted by those naturalists who are the 

 highest authorities relative to the species of fish, that there are, ex- 



