SALMQNID^E. 97 



" great lake-trout " S. lacustris (under which name it appears in Sampson's 

 Londonderry and Dubourdieu's Co. Down), supposing it to be identical with 

 tbe continental variety ; but of late years differences have been asserted to exist 

 between the British and foreign race. Jardine and Selby termed ours 8. ferox, 

 the specific name having been chosen to characterize its size and ferocious habits. 

 Jurine believed in the specific identity of all the forms of trout in the Lake of 

 Geneva ; and it would be but reasonable to expect that if the British 8. fario 

 under favourable conditions could attain the size of S. ferox, the continental 

 8. fario, which is the same species, would, under like conditions, also arrive at 

 being a great lake-trout. Moreau (vol. iii, p. 534) places among the synonyms 

 of Trutta (or Sal mo) fario, " La Forelle du Lac Leman, Fario Lemanus ;" and at 

 p. 536 observes, "La Truite feroce, Trutta ferox, Valenc, des eaux du Foretz est 

 une simple variete de la Truite vidgaire, et nullement une espece parti culiere." 



Although these authors have, in my opinion, been perfectly correct, still there 

 existed the statement of Dr. Giinther that structural differences existed among 

 the specimens in the British Museum, showing that 8. ferox possessed 56 to 

 57 vertebras and 43 to 49 caeca, while S. fario had 57 to 60 vertebrae and 33 to 47 

 caaca. I have, however, now shown (page 56) that examples of 8. fario may have 

 from 56 to 60 vertebrae, and likewise from 33 to 54 casca ; thus overlapping the entire 

 amount of variations ascribed to British forms. Sir William Jardine stated 

 that " the dorsal fin in 8. ferox contains 15 rays, and appears to be constant in 

 that number ;" and that " in form it is generally shorter proportionally and deeper 

 than in large specimens of S. fario." Sir J. Richardson distinguished between the 

 great lake-trout and brook-trout by the size attained. The tail "in adults is 

 perfectly square, or might even be described as slightly rounded at its extremity ; 

 in the young it is slightly forked, and appears to fill up gradually as the fish 

 advances in age." The relative position of the fins and the number of rays in 

 the dorsal, were said to vary from 2-4/11 or a total of from 13 to 15. Thompson 

 observes that he found from 33 to 49 caeca in various examples of S. ferox from 

 12 to 17 inches in length. 



I possess undoubted examples of the common brook-trout having from 13 to 

 15 dorsal rays : Moreau likewise in French specimens of the brook-trout found 3 

 or 4 undivided and 9 to 11 divided rays in the dorsal fin : likewise 3 undivided 

 and 7 to 9 divided anal rays : while as to the caudal fin being square in adults, so 

 it also is in large examples of the brook-trout. Yarrell (ed. 3, i, p. 281) gives an 

 illustration of a large Thames trout (a locality not frequented by S. ferox according 

 to authors), in which the caudal fin is as rounded as in any examples of great lake- 

 trout of similar size. It was a male, 28 inches long, having a hooked lower jaw, 

 while it weighed 11 lb. The comparative length of the head and height of the 

 body are almost identical with what obtains in an example of 8. ferox, 20 inches 

 long, from Llanberris, and which is in the British Museum. I examined a few 

 years since a specimen (which is still preserved) of trout, weighing upwards of 

 131b., taken from a large sheet of water at Alresford in Hampshire, which is well 

 stocked with coarse fish. This was one of about a dozen that some years 

 previously had been transferred from the contiguous stream, to which they could 

 not subsequently obtain access. Without a history of from whence the fish came, 

 I maintain that no ichthyologist could be certain whether any given specimen is 

 or is not a " great lake-trout." 



"The ti'out," says Dr. J. Davy, " when it feeds principally upon fish must be 

 extremely active and strong ; and consequently, from its predatory mobile habits, 

 acquires large teeth, large fleshy fins, thick skin and great pectoral fins for 

 turning." 



Variety r, — Salmo Cornubiensis, Plate CXIII, fig. 2. 



Trout, Boilase, Cornwall, p. 263, pi. xxvi, f. 1. 



Salmo Cornubiensis, Walb. Artedi, iii, p. 65; Bl. Schn. p. 421. 



This is a form mostly residing in small streams, and in which the parr finger 

 marks are continued through life, unless under changed conditions it increases 

 beyond its usual size, when these markings disappear. 



7 



