Fishes. 4795 



product of ova deposited under the gravel in October, November and 

 December of the previous year. To bring the question of age to an 

 issue there are obviously two ways: the first is to observe the pro- 

 gress of the ova surrounded by the natural influences, and undis- 

 turbed ; the second is to watch the development of the ova placed 

 in artificial circumstances. I naturally adopted the first, and for 

 this simple reason, that the salmon being an animal ferce natura, 

 or of the wilde ; it would, at all times, be difficult to say how far 

 an artificial locality might affect it. The result of my early obser- 

 vations have been stated briefly, and in much clearer terms by 

 Sir John Richardson, in his admirable ' Fauna Boreali-Americana,' 

 than by myself. I shall here quote from his work, premising that I 

 had already carefully observed the development of the ova of the 

 salmon deposited in the bed of the Whitadder, on the 2nd November, 

 1832; that on the 25th February I found the ova under the gravel 

 seemingly unchanged • that on the 23rd March changes were visible, 

 some of the young fry having burst their coverings, and were lying 

 embedded in the gravel. On the 1st of April most of the fry had 

 quitted their gravelly bed, and on the 19th May the river abounded 

 with smolts (some 7 or 8 inches in length) of various sizes, all covered 

 with scales. We now learned that smolts had been taken on the 5th 

 May in the same streams, which I considered as the young of an earlier 

 hatching, and as on a subsequent occasion I found ova unchanged on 

 the 10th April, and on the 17th April fry lying embedded in the gravel, 

 I inferred that the time of hatching varied according to circumstances 

 easily understood. Twenty-two smolts were taken from the river, 

 and examined with the greatest care ; they were male and female, in 

 tolerably equal numbers ; the male could often be recognised from 

 the female by the enlargement of the extremity of the lower jaw. It 

 is right to observe, that for two or three years the parr had disappeared 

 from the Whitadder. To return to the remarks made on this subject 

 by Sir John Richardson, extracted from his admirable work on the 

 American Fauna : — 



" Dr. Knox, in the appendix to the very able paper from which the 

 foregoing passages are abridged, remarks, that there are two cir- 

 cumstances which persons* of sound judgment and great experience 

 with regard to the salmon question still think undecided, or at least 

 demanding a more extended proof. The first is a series of experi- 

 ments to determine the growth of the salmon fry from the state of the 

 egg to its attaining the length of 6, 7, 8 or 9 inches, before which it is 

 * I alluded to Mr. R. Buist, of Perth. 



