ME. F. DAT ON THE LOG ll-I.E^^EN" TROUT. 



77 



the Loch-Leven trout, which affords the most notable example 

 of the pheiiomenoti referred to, it must, however, be kept in view, 

 as haviug an important bearing on the character of this fish, that 

 the loch which it inhabits had, most probably, at one time a 

 communication with the sea, and that the fish themselves possess 

 in a most remarkable degree the features of the salmon and the 

 sea-trout .... The fact of one of these trout having, in the 

 course of the present trial, been regarded by Professor Young as 

 a sea-trout, after examination, is a very strong testimony to the 

 difference between the characteristic features of the Loch-Leven 

 trout and those of all the non-migratory river-fish " (pp. 166, 167). 



In the year 1873 Sir James Maitland commenced fish-culture 

 at Howietoun, and selected as the form of trout which he con- 

 sidered would prove best adapted for this purpose the true 

 Loch-Leven breed, the eggs of whicli lie obtained at the lake, 

 and from which his present stock originated *. For some years 

 he has assisted me, and allowed every facility for examining 

 the fish in his establishment, while I have given very particular 

 attention to the following question. Is the Loch-Leven trout a 

 distinct species or merely a local race ? 



The first inquiry will therefore be. On what grounds has the 

 Loch-Leven trout been regarded as a distinct species ? Can any 

 persistent diff'erences from other trout be shown in its external 

 form, its internal organization, its tints, or the colour or taste of 

 its flesh ? 



As to external form, the Loch-Leven trout has been said to be 

 much less stout, its head shorter, its fins more pointed, while the rays 

 in its caudal fin are longer than those in the burn-trout ; the poste- 

 rior extremity of this fin is also said to be lunated and pointed at 

 both its upper and lower angles, and its pectoral fin is likewise 

 pointed. Also that the male has no hook on the lower jaw ; that its 

 maxillary bone is more feeble than in any other form of trout, and 

 that it never extends posteriorly beyond the hind margin of the 

 orbit. 



As to its body being less stout than that seen in burn-trout, 



* Others have likewise stocked pieces of water with these fish, but with vary- 

 ing success. Thus Knox ('Lone Glens of Scotland.' 1854) remarked upon " the 

 artificial Lake of Prestmannan, into which, some years ago, the beauteous Trout 

 of Loch Leven had been introduced. Under circumstances highly disadvanta- 

 geous they throve, notwithstanding, tolerably well, and even bred at the entrance 

 of a small stream which mainly supplies the lake" (p. 35). 



LINN. JOUilN. — ZOOLOGY, VOL. XX. 7 



