72 
THE CALIFORNIAN SALMON. 
lias been patented in tlie United States. It consists of a 
wooden box about two feet wide, and of the same depth, 
in which wooden trays, having wire netting in the bottom, 
are set, containing coarse gravel to allow the ova to fall 
through easily. The box is placed in the bed of the 
stream, where the water enters the pond in which the 
trout are kept, and the water is made to flow over the 
gravel with a rapid current, having a depth of 12 inches 
at the lower end, and gradually getting shallower towards 
the upper end, where the water enters the race. Beneath 
the trays containing the gravel, a revolving belt on two 
rollers is placed, with a handle above water, by turning 
which, and by the action of two small bevel wheels, the 
rollers and belt revolve. The boxes holding the gravel are 
each two feet square, and the bottom is made of wire 
netting of half-inch mesh. It is necessary that the fish 
should not be able to get past the spawning race, or have 
any other gravel beds to spawn in. The trays are filled 
with coarse gravel, which the fish mistake for the natural 
river bed, and the ova when deposited fall through, and are 
caught on the revolving belt, which is made of fine wire 
netting. A few turns of the handle bring the ova to one 
end, where they are caught in a pan, placed there for the 
purpose. If the race be covered, the ova may even be 
taken while the fish are spawning, without disturbing them. 
I have tried this race, but my fish did not spawn in it. 
In the Botanical Gardens at Ballarat the spawning race 
was more successful, however, and a quantity of ova was 
obtained from some trout kept in a small pond, and which 
ova were hatched out successfully. A full description of 
this spawning race, illustrated with plates, will be found 
in “ Domesticated Trout,” by Livingston Stone, a very 
valuable work on fish culture. Another way of obtaining 
ova from fish retained in artificial ponds, is by making a 
