200 SALMONID^ OF BRITAIN. 



Dr. Hamilton, v.P.z.s., communicated to me the following interesting facts 

 which came under his immediate observation in 1882. In the year 1867 two 

 separate lochs in Scotland were stocked with trout taken from Loch Morar. One of 

 these latter localities was 1882, was found by Dr. 



situated on a hill, Craig- v.'^\\ f^i(i Hamilton to have only 



moor, Inverness-shire, 1500 «^^^^^~-J,3 twenty -seven ceecal ap- 



ft. above sea level, it being ^j jijii^'T|w~^- pendages, while the length 



a mile and a half in cir- ^^mMk. Illr^^N^ °'^ *'^^ head was equal to 

 cumference, and possess- ^^^^^k § fll ^w ^^^ height of the body, or 

 ing a sandy and weedy ^^^^Uki/W ^^ "^ ^'^^^ °^ *^® total 



bottom. Here the fish ^^^^''■'W|il,'||i length. The tail fin was 



never attain to a pound's ^5/^ftv|ill nearly square at the 



weight, but are long and //WimlMl extremity. The second 



lanky, rise freely to the ^ IfflllKII locality, also stocked in 



fly, and give good sport llliwlii 1867 from the same loch, 



to the angler. Externally b1"IP;'I| ^^^ termed Loch Shean 



their sides and under sur- l^ilf More, Arisaig, Inverness- 



face have a golden tinge, ^^^r shire, is sm^aller than the 



whUe they are covered pjg 47 c^^al appendages preceding one, and not 

 with numerous red spots ; 49, and also cystic duct of a very deep, but the water 

 having been cooked the brook trout from the Wind- is dark - coloured, while 

 flesh cuts white. A female "^"sh, i natural size. ^jje bottom appears to be 



10^ in. long, examined in covered with small rocks. 



The fish are very game, and rise boldly. The head is very dark, nearly black, 

 the sides yellowish olive, and the eyes prominent. A few (about ten) red spots 

 are present on each side, and thirteen to fourteen black ones ; having been 

 cooked the flesh is yellowish pink. Ur. Hamilton examined a female lOi in. 

 long, and found forty csecal appendages, while the length of the head was 

 one-sixth, and the height of the body one-quarter of the total length. The 

 tail fin was nearly square at its extremity. Here we observe the progeny of 

 trout transferred from a single piece of water, Loch Morar, in 1867, had so 

 altered by 1882, due to changed conditions of life, that they would be distinct 

 species as recognized by some naturalists. If the difference of living in these 

 two localities sets up such changes that only twenty-seven caecal appendages are 

 developed in one form and forty in the other ; that the depth of the body is 

 nearly one-sixth of the length in the first, but a quarter in the second ; if one 

 possesses numerous red spots, while the second has but few, but many black ones, 

 it does not appear that we need go so far as Tasmania to prove how inconstant in 

 trout are external colours or form, as well as the inadmissibility of accepting the 

 number of ceecal appendages as a basis for forming species. 



Colours. — Among trout inhabiting fresh waters and estuaries large differences 

 in the tints and markings are perceptible as might be expected* (pp. 6, 144, 145). 

 In short, as has been already referred to, we may perceive fresh-water forms 

 approaching sea trout in colour as those of Loch Crasspuil (p. 190), and of which 

 occasional examples may be seen in Loch Lomond and elsewhere. While there 

 are many cir6umstances affecting colour, as the state of health of the fish, the 

 period of the year, if it is in a breeding condition, its age, the quality and amount 

 of food it can obtain, the character of the water and its surroundings, and whether 

 the stream is rapid or sluggish. In some of the silvery forms there are merely 

 black spots which may be round, and are often encompassed by a light ring,t 



* St. John, Natural History and Sport in Moray, p. 25, observed, " Put a living black burn 

 trout into a white basin of water, and it becomes within half-an-hour of a light colour. Keep the 

 fish living in a white jar for some days and it becomes absolutely white : but put it into a dark- 

 coloured or black vessel, and although on first being placed there, the white-coloured fish shows 

 most conspicuously on the black ground, in a quarter of an hour it becomes as dark coloured as 

 the bottom of the jar and consequently difficult to be seen." 



t Sometimes black spots on these fishes become surrounded after death with a light ring, 

 while in others red spots may appear which were not seen when they were living. Also some fish 

 when not in good condition will lose their colours very rapidly. 



