THE CALIFORNIAN SALMON. 
51 
but many were adhering in clusters, most of which I knew 
could not live, but which looked healthy enough at the 
time. 
The next morning over one hundred young salmon were 
hatched, and they were lively little fellows even at that 
early stage of their existence. "When touched with a 
feather they would start off and swim round in a circle, 
and settle down again amongst the gravel. On the re- 
mainder of the ova being transferred to the hatching-boxes, 
numbers of the young fish were found to have hatched 
out during the night, and during the day four or five 
hundred made their appearance. 
The ovum of the Californian salmon is larger than that 
of the British species. It measures almost exactly a third 
of an inch in diameter. It is of a transparent pink colour, 
and is nearly globular, being slightly elongated. The 
young fish is about an inch long, and it has attached to it 
the umbilical sac containing the yolk of the egg, which is 
of a clear transparent red colour, and seems quite as large 
as the egg from which it has emerged. This sac contains 
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, over which a stream of water is 
allowed to run. The temperature of the water is a most 
important point, and I selected a spring from its being of 
a uniform degree of cold, and from its freedom from sedi- 
ment, which, by settling on the egg, interferes with the 
supply of oxygen necessary for its 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 
n 2 
