22 THE SPORTING FISH 



In about thirty-five or forty days from the time 

 of hatching, the yolk-bag disappears, and the fry 

 becomes a perfect little fish of about an inch long, 

 with the fins separated and properly developed, 

 and the tail deeply forked at the end. The general 

 colour now also changes to a light brown ; and the 

 sides are indistinctly crossed by nine or ten trans- 

 verse dusky bars, or Parr-marks, characteristic of 

 all the species of the genus Salmo when in an im- 

 mature state, and which in the true Salmon remain 

 more or less visible even in a Smolt or Parr six 

 inches long. If the scales are removed, the marks 

 are much more obvious. The differences in ap- 

 pearance, in fact, between the fry of the Salmon, 

 Bull-Trout, and Sea-Trout, and probably also be- 

 tween the fry of the other species of the same 

 genus, are so trifling as to be scarcely perceptible 

 unless upon very close examination, and are, more- 

 over, liable to constant variations with local cir- 

 cumstances. According, however, to Sir William 

 Jardine, the fry of the common Trout (Salmo far io) 

 may always be distinguished from that of either 

 of the three migratory species by its having the 

 extremity of the second dorsal, or adipose, fin 

 fringed with orange. 



Up to the period of their first assuming the 

 Parr-marks the Salmon-fry are unable to move 

 about much, owing to the presence of the vitelline, 

 or yolk-bag, which impedes their motions in swim- 

 ming, and obliges them when at rest to lie perpe- 



