420 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [26] 
crude hatching-box could be made for holding them during the night. 
This consisted simply of a small wooden box, with a wire-cloth bottom. 
When completed it was placed in the water, and, after being properly 
secured to the piling of a wharf, the eggs were poured into it. The fol- 
lowing morning a number of larger and better boxes were made. The 
one giving the best results was so arranged that the smallest waves would 
cause a flow of water into it, and thus keep the eggs in constant motion. 
It was very similar in shape to the boxes used in hatching the eggs of the 
cod, having, in addition to the wire-cloth bottom, openings on two sides, 
even with the water-line. Just below these, on the outside of the box, 
were wooden floats about three inches wide, these being placed at an 
angle with the surface of the water, so that a portion of each wave, as 
it came in contact with the float, would run up the slight incline and, 
after reaching the highest point, pass down through the wire-cloth into 
the box, giving a constant circulation, the water being introduced from 
above and passing out through the bottom, thus giving the best possi- 
ble motion to the eggs. Other boxes were arranged in the ordinary 
way to utilize the action of tides and currents; these were set obliquely 
in the water, so that the current would force the water through the 
wire-cloth bottom, thus keeping the eggs in constant motion. 
The first eggs secured were washed out of the box during a storm 
and were lost, but the other boxes were at once provided with covers, 
to obviate any further loss from this source. From this time little diffi- 
culty was experienced, and the eggs were easily hatched. The number 
of eggs taken during the experiments was about half a million, these 
being secured from 8 or 9 females, at different times, the largest num- 
ber taken from any fish being estimated at 100,000. The loss in hatch- 
ing, if we except the eggs washed out, was very small, and in one 
instance did not exceed 10 per cent., while 60 or 70 per cent. of nearly 
every lot developed into young fish. 
The time of hatching varied greatly with the temperature of the 
water, the embryo developing much more rapidly in warm than in cold 
water. The average temperature during the experiments at Crisfield 
was 84° Fahr. Under these thermal conditions the line of the fish could 
be readily seen by the unaided eye 10 hours after the egg had been 
brought in contact with the milt. In 154 hours the first fish were seen; 
24 hours later, or 18 hours from the fish, fully half of the eggs had 
hatched, and inside of 20 hours all were out. Later experiments showed 
that in water at a temperature of 78° 24 Irours were required for hatch- 
ing. It is thus seen that the eggs of the mackerel develop more rapidly 
than those of any other species with which the Commission is familiar.* 
*During the experiments with the eggs of the mackerel many moon-fish (Cheto- 
dipterus faber) were taken in the pounds. A number of spawning fish were found 
among them, from which I secured several lots of eggs that were successfully hatched. 
These fish spawn in Chesapeake Bay during June, July, and August. The eggs are 
buoyant, and though a trifle larger than those ‘of the mackerel they hatch in the 
same time. This is the first time that eggs of the moon-fish, or porgy, as it is more 
commonly called, have been artificially hatched. 
