STORMONTFIELD EXPERIMENT. 33 



In the spring of the year 1854, Mr Buist, the 

 conservator of the Tay, obtained some ova, nearly 

 ready for hatching, from a ford on the river, and 

 placed a dozen of the grabs of the May-fly 

 (ephemera), taken from the same bed, along 

 with them in a vessel, which was supplied with 

 water by a syphon of thread. In a few days 

 the grubs had devoured one of the eggs, and 

 in a few days more the whole were devoured; 

 but, previous to that time, two or three of 

 the grubs left their covering, and came forth 

 as the May-fly. We watched them carefully 

 while in the act of feeding, and found five 

 or six of the grubs firmly fixed to an ovum, which 

 they never left until totally eaten up. These 

 animals are not the scavengers of the river, for, 

 in this instance, the ova were alive. Again, in a 

 small but complete artificial rearing apparatus, 

 which we have had in operation for many years, 

 and which is supplied with filtered water, we 

 deposited in two boxes, on the 26th November, 

 1859, a quantity of salmon ova, fecundated by 

 the milt of a male salmon, and on the 30th of 

 the same month a small quantity of sea-trout ova, 

 fecundated by the milt of a male salmon also. 

 The progress made by both was very satisfactory; 



