APPENDIX. 175 



muscular exertion of their tails upon their sides, and by gentle 

 contact emit their ova, which is carried off by the action of 

 the water, and gradually subsides immediately behind them, 

 mixed up with the gravel. This operation is carried on for a 

 fortnight by each pair of fish, if they are not disturbed, when 

 the process is completed. The general opinion is, that first the 

 fish dig a hole, and deposit their spawn therein. If those 

 people were only to give the subject a moment's serious reflec- 

 tion, they would at once find that such a supposition could not 

 in point of fact ever be realised ; as, with every • additional 

 agitation of the gravel in the bottom of the hole, the roe would 

 be thrown out of it along with the gravel. By the time the 

 spawning operation is ended, a hiU or molecule of considerable 

 size has gradually accumulated immediately behiud the hole 

 or bed excavated by the fish, and any person taking the trouble 

 of examining that mound will find the ova mixed up in it ; 

 and were we as conversant with the laws of hydraulics as 

 Nature is, I have no doubt we should find the ova more secure 

 in mounds immediately below the excavation, than if deposited 

 in that excavation. Salmon do not spawn in pools, because, 

 without the action of running water, they could not cover in 

 their ova, — without which precaution it would be left exposed 

 to be dispersed by floods, or swallowed up by other fishes. 

 Kunning water is not, however, essential to the vivification of 

 the young fish, for we find that the ova of carp, breams, barbel, 

 and trout that inhabit ponds, come to perfection in still 

 water. 



M. I have read in a pamphlet that the salmon dig the 

 spawning hole or bed with their " snouts." 



H. By its physical conformation a naturalist would at once 

 pronounce that it is an impossibility for that fish to apply its 

 snout to a digging purpose. In the first place, the creature 

 has no neck, and consequently has not the power of moving 

 its head up or down without a corresponding movement of its 

 entire body ; and, even if the fish ;retreated a few yards, 

 reculer pour mieux sauter, to give it an impulse, it would stiU be 

 necessary for it to raise its tail out of the water at an angle of 

 45°, to enable it, like a pick-axe, to knock its snout against the 



