294 ADDITIONAL NOTES. 



time required for which, may be from four to six months. Its 

 spawning season, he states, extends over six months, commencing 

 about the middle of September, and ending about the middle of 

 March; the height of the process being from the middle of 

 November to the middle of December, the earlier the safer, 

 each fish spawning where it had been bred, male and female 

 associated, side by side, but not" in contact, the spawn being 

 shed on the ova, immediately on exclusion, both fishes co- 

 operating in making the spawn-bed in the gravel, and in 

 covering it as soon as laid. This operation on the part of the 

 male and female occupies from five to ten days. The time of 

 hatching the ova he estimates at from one hundred to one hun- 

 dred and forty days, varying with the temperature of the water. 

 During the greater part of the first month, the young fish, then 

 hardly an inch long (three quarters of an inch when first pro- 

 duced), mainly depends for its support on the yolk contained in 

 the vitelline sac, which, about the end of that time, ceases to be 

 seen externally. After two months, it loses its early peculiarities, 

 the most marked of which is a posterior surrounding marginal 

 fin, very like that of the tadpole ; now, its transverse markings 

 (bars) begin to appear. At four months it is about two inches in 

 length ; at six, about three ; at eight and nine, it is very little 

 larger, but thicker ; at ten, it is from three to three and a half, 

 when its transverse bars begin to disappear, the silvery scales, 

 those of the smolt covering and obscuring them; finally, at 

 twelve months, it is from four to six inches, on an average about 

 five, and is now a smolt, with its silvery migratory coat, and 

 commonly migrates to the sea, descending in small shoals, from 

 the middle of April to the middle of May. After remaining 

 about eight weeks in salt water, it returns a grilse, vastly in- 

 creased in size, varying in weight, according to the time it has 

 remained in the sea, from three to eight pounds. 



Mr. Shaw's observations on the salmon are to be found in the 

 14th vol. of the " Transactions of the Royal Society of Edinburgh," 

 and his observations on the sea-trout, in the 15th vol. of the 

 same publication ; Mr. Young's, on the salmon, in the last-men- 

 tioned volume, and more in detail in his " Natural History of the 

 Salmon." Happily they agree in their general statements, espe- 

 cially in relation to the time required for the maturation of the 

 ova the production of the young fish. The circumstance of 



