THE SALMON-TROUT. 187 



impregnation, and exhibiting five successive stages, 

 from the day of hatching to the age of nine months. 

 At the age of six months they bear a less marked 

 resemblance to the young of the true salmon in the 

 parr state than might have been supposed, and as 

 they increase in age and dimensions the likeness 

 becomes still slighter. But on comparing them 

 with the young of common river trout, the resem- 

 blance is close and striking. Their general form 

 and outline are less elegant than those of the young 

 of salmon. 



How long this not easily definable species re- 

 mains in the sea during its first excursion there, 

 we are not prepared to say, for it seems that it 

 too, either attains a rapid increase during a short 

 sojourn in ocean's green domains, or " hid in some 

 vacant interlunar cave," rests for a longer period 

 than supposed in deep translucent waters. Dr. 

 Parnell supposes, that those hatched in March 

 and April of one season, remain in the river till 

 May or June of that which follows, by which time 

 they have assumed a silvery lustre, and attained a 

 length of from six to eight inches ; that they then 

 descend to the sea, where they remain about two 

 months, and afterwards ascend the rivers as her- 

 lings or whitlings (Salmo albus of Dr. Fleming), 

 in which state they measure from ten to twelve 

 inches.* By this time the back has become of a 



* It is probable that these fish are older than Dr. Parnell sup- 

 poses, although it has not yet been proved that (like salmon smolts) 

 the majority do not attain their silvery lustre till the termination of 

 the second year. Mr. Shaw suspects they migrate when about the 



