Second Importation of Calif ornian Ova. 33 



the food of the young salmon for three or four 

 weeks, and is gradually absorbed, becoming 

 smaller as the young fish grows. 



The hatching process is effected simply by 

 placing the ova on a layer of gravel, oyer 

 which a stream of water is allowed to run. 

 The temperature of the water is a most im- 

 portant point, and I selected a spring from its 

 being of a uniform degree of cold, and from its 

 freedom from sediment, which, by settling on 

 the eggs, would interfere with the supply of 

 oxygen necessary for their vivification. As the 

 supply from the spring is limited, being only 

 four to five pints per minute, I had a pipe laid 

 down from the creek to supply two filters, the 

 water from which is used to increase the 

 stream. The water from the pipe can be shut 

 off entirely when its temperature is too high, 

 but, so far, the difference has not been great 

 between the water from it and that of the 

 spring. The temperature of the spring is 

 55 deg., and the pipe supply has risen on hot 

 days to 62 deg., but the young fish did not 

 seem to suffer in the slightest, and those in 

 the warmest water are the furthest advanced. 

 The hatching went on favourably, but a large 



