960 EEPORT OP COMMISSIONER OF FISH AND FISHERIES. 



the trays and the sides, narrow crevices into which the young fish may 

 wriggle, to the great danger of being crushed to death. After all are 

 hatched the trays are no longer of service, and the support can then be 

 taken out without injuring the fish, leaving an unobstructed floor. 



Fig. 9- 



The trays which rest on the supports just described need no legs. To 

 use a trough to its full capacity, however, anoflier series of trays, resting on 

 the first series, is necessary, and sometimes a third series resting on the 



Fig, 10. 

 second. The trays used in these upper series must be provided with legs 

 half an inch long, obtained by driving four nails into the under side of the 

 frame. (See Figures 9 and 10.) This keeps the trays half an inch apart, 

 the proper distance when there is a space of three-quarters or an inch un- 

 der the lower trays. It is, however, recommended to partially close the 

 lower space at first by a few movable cleats, which can be removed when 

 the fish begin to come out of the shell and accumulate on the floor. These 

 precautions are to guard against a too free flow of water underneath the 

 trays, where it would at that time be wasted, and perhaps leave a scanty 



supply for the eggs above. As a 

 further precaution, with the same 

 end in view, if the trays do not fit 

 the troughs pretty closely they may 

 be placed obliquely, so that two op- 

 posite corners will prevent a draft of 

 Fig. 11. water down the side. (See Fig. 11.) 



