44 



Mr J. J. Armistead 



[Feb. 14, 



incubation going on meanwhile ; and I do not know that there is a 

 much more interesting sight than to watch the development of the 

 embryos. First of all, a short time after laying the eggs down, we find 

 the process of segmentation setting in. There is first a cell, and then 

 a division into two, then into four, then into eight, and sixteen, and so 

 on ; and so the process goes on till at last we can detect the chorda 

 dorsalis, or notochord ; and at last we see two little black specks 

 which are the eyes of the fish, and when we see this we know that the 

 eggs are almost in a state to bear packing for New Zealand or 

 Australia. We have sent a great many eggs out to New Zealand and 

 Australia, and a great deal of trouble was occasioned in the early 

 days of fish culture by not knowing the exact time at which to pack 

 them. We have found that very soon after the eye-spots appear there 

 is a perceptible motion of the tail of the fish, and also the first appear- 

 ance of red blood. When we see that, we know that the eggs are fit 

 to be packed, and they travel beautifully on the long voyage to the 

 Antipodes. Here we have the tubs and the operator, and the fish 

 ready to spawn. In due course of time the eggs hatch. The little 

 fish does not look very much like a fish at first. They are very 

 lively and very interesting creatures. Some of the bottles contain 

 ova of trout. One bottle has the ova of salmon in it. The salmon 

 eggs are marked, and the trout eggs are not, so that the mark on the 

 bottle shows which sort it is. There are the little fish in what we call 

 the alevin stage, with the umbilical sac attached (Fig. 4). Through 



Alevin. 



a microscope you get a most interesting sight by looking at these little 

 fellows. You can see the circulation of the blood, and the sight is an 

 exceedingly interesting one. Very naturally, delicate little things 

 like these require a great deal of care. Notwithstanding, we have 

 worked the thing to such a point now that we have very little trouble 

 with them during this stage of their existence, if the hatchery appara- 

 tus be kept clean. The little pectoral fins are continually moving, 

 and cause currents of water which are passing through the gills, so 

 that the little fish get a supply of oxygen. If we keep the boxes free 



