Varieties of the Brook Trout. 233 



from the other, this question might fairly be put, Is the light- 

 coloured trout a distinct species ? If not, what is the cause of 

 the abnormality ? The so-called Salmo oquassa (Girard),* met 

 with in the deep lakes in Maine, would seem from description 

 to be closely allied to if not identical with the last. Its 

 local name, " blue back," with the general colourings of the 

 sides and lower parts, very closely approach the above, which 

 therefore may be considered distinct from S . fontinalis—2X all 

 events, as usually met with in New Brunswick. I do believe 

 however, if we were to note all the peculiarities of the fresh- 

 water salmonoids of even the region now under consideration, 

 that as far as differences are concerned the number hitherto 

 recorded might be quadrupled. Indeed the question, "What 

 constitutes a species ?" may well be asked in connection with 

 the salmon family, but we can scarcely blame the cabinet 

 naturalist, with only skins, preserved specimens in spirits, 

 drawings, and descriptions before him, should he be disposed 

 to multiply their numbers. A feasible explanation is the 

 interbreeding of allied species forming fertile varieties, which 

 under such conditions would be increasing the already 

 extraordinary number of forms which, even as far as the 

 British Isles are concerned, have become very numerous, 

 indeed perhaps too numerous.! By this I mean that if we 

 studied their habits and haunts as carefully as we do speci- 

 mens, no doubt many so-called species would turn out to be 

 only seasonal conditions or local forms. 



The brook trout, unlike its European congeners, seldom 

 refuses the earthworm at any season, but in July will readily 

 jump at the artificial fly, generally preferring a " red hackle." 

 In the numerous streams it is met with in enormous numbers ; 

 perhaps no salmonoid is more prolific, whilst few, if any, excel 



* " Boston Society of Natural History," vol. iv., p. 262. 



f See Gunthur in his admirable monograph published in the "Proceed- 

 ings of the Zoological Society," and also the "Catalogue of Fishes " in the 

 British Museum. 1862. 



