300 THE BIOLOGY OF THE SEASONS 



may go on depositing eggs at intervals for several successive 

 days, and the rival males fight with one another fiercely 

 for their place in her train. The hooked and some- 

 what distorted jaws of big males seem to be adapted as 

 weapons. 



The eggs have many enemies, such as trout, eels, water- 

 fowl, and insect larvae, which have plenty of time to find 

 them out, for three or four months must elapse before they 

 are ready to be hatched. There are many other risks of 

 failure ; they may be left exposed by a great drought, or 

 washed away by a flood, or smothered by a shifting of the 

 gravel. It. need hardly be said, therefore, that only a 

 small proportion of the eggs become " fry/* 



The newly-hatched young are very sluggish, and lie 

 among the stones, living on their legacy of yolk, which 

 may last for fifty days. It lies in a ventral sac, which 

 rather inhibits the little creature's movements. About 

 the eighth week after hatching, the yolk has been wholly 

 absorbed, and the larvae, or " fry," are about an inch long. 

 They begin to feed greedily on minute organisms in the 

 water, they grow quickly (in marked contrast to their slow 

 development), in two months they double their size, and 

 by the end of a year they are somewhat trout-like " parr," 

 about four inches in length. It is interesting to recall 

 that it is only some seventy years since Shaw, at Drum- 

 lanrig, proved that the parr is the young salmon, and not 

 a member of a supposed related species (Salmo salmulus) 

 of diminutive size. 



In their second year (in most cases) the young salmon 

 lose their trout-like markings and put on their " sea- jacket " 

 tints of olive and gold overspread with glistening silver. 

 In other words, they become silvery " smolts," which migrate 

 to the sea. The descent of the smolt to the sea, Mr. 

 Calderwood writes, " is prompted by a most powerful 



