412 ME. F. DAT ON BEITISH SALMONES. 



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 is different ; the number of rays in the dorsal 

 varies from 2-4/11 or 13 to 15 ; and the scales along the lateral 

 line are of a different form. Thompson observes that he found 

 from 33 to 49 cseca 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 ; vs^hile as to the caudal fin being 

 square in adults, so it is also in large examples of the brook -trout. 

 Tarrell (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 oi S.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, weigh- 

 ing upwards of 13 lb., taken from a large sheet of water at Aires- 

 ford in Hampshire, which is well stocked with coarse fish. This was 

 one of about a dozen that some years previously had been trans- 

 ferred from the contiguous stream, to which they could, not subse- 

 quently obtain access. It is believed that in such situations trout 

 do not breed, but, if food is plentiful, they attain to a large size. 

 "Without a history of whence this fish came, I maintain that no 

 ichthyologist could be certain whether it is or is not a great 

 lake-trout. 



" The trout," says Dr. J. Davy, " when it feeds principally upon 

 fish must be extremely active and strong ; consequently, from its 

 predatory mobile habits, acquires large teeth, large fleshy fins, 

 thick skin, and great pectoral fins for turning. When it feeds 

 on shell-fish, it gets the stomach of the charr and its colours as 

 in the Grillaroo trout." 



A race of trout 'found in Ireland has from time immemorial 

 been known as the Gillaroo, distinguished by the thickness of the 

 middle coat of its stomach. The first mention of this fish is in a 

 paper by the Hon. D. Barrington, read at the Eoyal Society, 

 December 23, 1773, when he observed " there are no exterior 

 marks by which the species on the table can be distinguished 

 from the common trout." The fishermen observed that " the 



