the Salmon, Herring, and Vendace. 479 



so as to enable me to speak positively of a fact of the most singu- 

 lar nature, viz. that they should refuse all food whilst in a state 

 of confinement. I am inclined to believe that this is the case, 

 and that this is the exact statement of all the observations that 

 have ever been made upon them, that when removed from the 

 gravel-bed, on their first bursting the shell, they are somewhat 

 less than an inch in length, with the yolk of the ovum very large, 

 and in the usual situation,~that they remain in this state under 

 the gravel about eight days and no longer, that they then emerge 

 from the gravel, and are seen then for a short time to haunt the 

 edges of the river in shallow places, that the ova will become de- 

 veloped, if taken from the gravel, and put in water, to all appear- 

 ance as well as if they had been allowed to remain under the gravel, 

 and, if not exposed to too high a temperature, will pass through 

 the same changes, in all probability, in the same period of time. I 

 do not believe, however, that in the latter circumstances (i. e. in 

 confinement) their life can be prolonged above ten days from the 

 time of their bursting the shell ; at least, this I have myself put 

 to experiment, and all persons to whom I have spoken on the 

 subject agree with me. In accordance with these remarks, it was 

 found, that, on reopening the spawning-bed on the 1st April, or 

 in about eight days from the time of the bursting of the shell, by 

 far the greater number had evidently already quitted the gravel, 

 so that only a very few remained ; in fact, there was not one for 

 hundreds which existed there the week before. These had at- 

 tained the same length as the ones kept in the house during the 

 interval, but the latter were darker in colour, in all probability 

 from the exposure to light. The temperature of the gravel-bed 

 was 41 at 9 o'clock A. M., that of the water about two degrees 

 higher. At 12 o'clock the temperature of the water had risen to 

 45, and of the air to 55. The temperature of the gravel-beds 

 during winter is probably seldom under 39, but we speak from 

 rather a limited observation as to this matter. 



