460 ME. F. DAY ON THE BREEDING OF SALMON FEOM PARENTS 



slime. The fins also become more muscular. However, on the return of spring, they 

 resume their wonted beautiful silvery colouring, aud the fins, the cartilaginous portions 

 of which are frequently damaged during the winter floods, grow up and acquire their 

 former outline." 



Different authors have assigned various reasons why a parr on becoming a smolt (which 

 it does, as a rule, when commencing its seaward journey) assumes a silvery livery. Davy * 

 suggested " that the young remain in fresh water until they have acquired not only a 

 certain size and strength, but also additional scales, fitting them, in their smolt stage, to 

 endure without injury the contact of the saline medium." Couch demurred to such an 

 opinion in 1866, observing that the silvery colour of smolts is not due to their acquiring 

 additional scales, but owing to a deposit of bright soft matter which shines through the 

 transparent scales. Dr. Giinther f remarks, respecting the River-Trout, that they " fre- 

 quently retain the parr-marks all their lifetime ; at certain seasons a new coat of scales 

 overlays the parr-marks, rendering them invisible for a time, but they reappear in time, 

 or are distinct as soon as the scales are removed. When the Salmones have passed this 

 parr-stage .... a new coat of scales overlays the parr-marks." But as these fish do not 

 shed their scales, Dr. Giinther appears to hold to the untenable proposition that an 

 additional coat of scales is developed on these fishes at certain periods +. It was like- 

 wise stated in one of the conference papers read at the " Great International Fisheries 

 Exhibition " in 1883 §, that the young of the true Salmon " do not venture into the sea 

 till another skin of glistening scales has been formed over their first skin. They then 

 receive the name of smolts. If put into salt water before getting this silvery dress 

 they die." I do not propose here entering upon the discussion of these opinions, so 

 wide spread, but nevertheless entirely erroneous. Any one who will examine a series 

 of specimens can readily verify for himself that there never is an extra coat of scales 

 as above stated. 



Before concluding this portion of my paper, I may observe that the teeth in the vomer 

 of a parr generally are as follows : — three on the head of that bone, below or behind 

 that a pair, next two placed one at an angle to the other, and subsequently eight in a 

 single row, but with their points somewhat divergent. There is very little change seen 

 in those of the smolt, while in a grilse 13 inches long, that spawned this year, the same 

 dentition prevails. This raises the question whether the loss of teeth, as generally seen, 

 is not partly due to the hardness of the food they consume ; this, however, is not the 

 case in the Howietoun pond, as what they are fed upon is soft. 



I omit any detailed description of the grilse, and decline entering upon a lengthened 

 discussion of the decision of a Committee of the Commissioners of the river Tweed, 



* ' Physiological Researches,' 18G3, p. 250. 

 t ' Introductiou to the Study of Fishes,' 18S0, p. G32. 



% See Proceedings of Zoological Society, 1884, p. 22, showing the impossibility of an extra coat of scales being 

 developed. 



§ " Salmon and Salmon Fisheries," by D. Milne Holme. (Conference Papere, p. 4.) 



