76 THE SEA-TROUT 



days, the sac being wholly absorbed, the little fish, perfect in shape, 

 may be seen darting about amongst the gravel. This is the " sea-trout 

 fry." 



It may be convenient here (reverting to Mr. Regan's dictum already 

 quoted) to consider in one view various differences, no doubt more or 

 less superficial, which I have noted as occurring between " the young " 

 of salmon, sea-trout and trout. 



1. Salmon eggs are uniformly round in shape while those of sea- 



trout and trout are very irregular. 



2. The eggs of salmon are practically uniform in colour; those of 



sea-trout and trout vary considerably. 



3. Salmon eggs take longer to hatch out than sea-trout eggs and 



still longer than trout eggs. 



4. The colour of the respective alevins differs materially and does 



not seem to be necessarily dependent on the colour of the 

 respective eggs. The salmon alevin is always pale flesh 

 coloured — " like finely chopped carrot " as it was once 

 expressed to me ; the sea-trout alevin is at first crimson-red 

 in tinge and rapidly develops a dark brown colour on the 

 back. Trout alevins are much greyer than the other two all 

 the time they are alevins. 



5. The salmon alevin is appreciably larger than the other two on 



hatching, its body being markedly longer, while the greatest 

 development of the umbihcal sac appears to be midway in 

 the body rather than near the throat as in the case of sea-trout 

 and trout. 



6. On being hatched, salmon alevins lie, as it were, dormant for 



about eight days, the same period of inertia with sea-trout 

 lasting only two days. 



7. The eye of the salmon fry is appreciably larger than that of 



the sea-trout or trout fry. 



8. At the earliest stage, parr marks are most sharply defined on 



the salmon, less so on the trout, and least on the sea-trout. 



