472 Dr KNOX on the Natural History of 



gravel in the form of an egg, to its ultimate disappearance from 

 the fresh water streams, which formed its habitat whilst infan- 

 tile ; remarking, that every thing stated therein fell under my 

 own immediate personal observation. I have thought it preferable 

 thus to narrate at some length, and almost in the order of their 

 occurrence, a series of observations on the generation of the ova, 

 to any other mode of describing the natural history of the sal- 

 mon-smolt or fry. It is difficult to speak of matters of this 

 kind in the abstract, or under the form of conclusions or results ; 

 too much has been already attempted in this way. Besides, I had 

 it not altogether in my power to compare these observations with 

 my previous ones, having taken at the time few notes of any con- 

 sequence, and trusted too much to recollection ; and as no other 

 person had given to the public a series of similar observations, I 

 have thought it better to detail them to this learned Body, thus 

 connecting the natural history of the salmon fry with the grown 

 or adult salmon. 



THE SMOLT, FRY, OR YOUNG OF THE SALMON. 



November 2. Salmon are observed to be spawning in the va- 

 rious tributary streams of the Tweed which join that river from 

 the north, and a pair are watched. The ova observed to be de- 

 posited near the sources of the stream on the 2d November, and 

 covered up with gravel in the usual way. 



February 25. On the 25th February, or 116 days after be- 

 ing deposited, the ova, on being dug up, are found to be un- 

 changed. If removed at this time, and preserved in bottles filled 

 with water, the development of the egg may be hastened almost 

 immediately, by being put into warm rooms ; it is not necessary 

 to change the water. The fry so hatched, i. e. artificially, cannot 

 be preserved alive in bottles longer than ten days ; they eat no- 

 thing during their confinement. 



