478 Dr Kwx on the Natural History of 



may deposit their ova late in May, and that these may be de- 

 veloped in a few days, I reply, that all the elements of a correct 

 observation are wanting to render the statement worthy of any 

 notice. It is true, and I have shewn it myself, that the ova may 

 be hurried on by artificial heat, and that consequently the warmth 

 of April and May may effect the same changes in the ova, and 

 bring them forward equally with those deposited in October and 

 November ; but still this must have its limits, and the circum- 

 stances under which it is said to take place are totally unknown. 

 Though the young fish have cast their sloughs, and, in the ob- 

 servations now detailed, had done so on the 23d of March, all 

 the ova, however, in the bed had not done so, but by far the 

 greater numbers ; so that for one ovum found entire, there were 

 hundreds which had quitted this state, and assumed the form of 

 fishes. Of the fry which had burst the shell on the 23d March, 

 several were removed on the 25th March, and put into a common 

 tumbler-glass full of water, whilst some were carried to town in a 

 small phial. Of six removed in this way,, one only reached town 

 alive : it remained healthy and lively for five days ; but, so, 

 so soon as a small portion of bread was thrown into the water 

 sufficient to tinge it, the fish almost instantly expired. Those 

 left in a house near the river from whence they were taken, 

 were found, on the 1st April, to be perfectly healthy, and had 

 grown considerably. They had become much darker, and were 

 about an inch in length ; a considerable part of the yolk was 

 still external to the abdomen.: the water had scarcely been 

 changed, and it would seem that this is not necessary ; at all 

 events, it certainly can be overdone, not only as regards the 

 ova, but the very young fry also. It has been observed, that 

 whilst confined in this way they refuse all sorts of food, even that 

 on which we are assured, by positive and personal observation, 

 they ultimately live, after they have been some time at large in 

 the river. I regret that I did not make the experiment myself, 



