110 Part III.—Twenty-fourth Annual Report 
then passes on to the hatching apparatus. These are 22 in numuer, and 
are of the Dannevig pattern. They are shown in fig. 1, pl. VII., which isa 
view of the inside of one end of the hatchery. The apparatus on each 
side are supplied by separate pipes. 
The pump-house is contiguous to the hatchery room, and opens into it, 
It is provided with three Worthington direct-acting steam pumps, specially 
made for use with sea water, and brass lined. They are shown in fig. 2, 
pl. VII. They are so fitted up that any one of them, or all together, can 
be used to pump water from the filter-chamber, either to the reservoir or 
to the pond; there are two suction pipes, one for the large pump and one 
for the two smaller pumps. Steam is supplied by an upright donkey 
boiler, with two tubes, which is fitted with an injector and pump, but the 
town water supply can be used direct, the working pressure being usually 
40lbs. The pump-house measures 18 feet 10 inches by 15 feet; its 
position is shown at 0 in fig. 1, pl. VI. 
The tank-house, which is used in connection with the scientific 
researches at the laboratory, is built partly over one end of the large 
spawning pond (fig. 2 ¢, pl. WI.), and there is a platform along this side 
over the pond. It is provided with six concrete tanks, four of which 
have plate glass in front and back, and the other two plate-glass fronts 
only. The latter are 6 feet 4 inches long, 4 feet 3 inches deep, and 34 feet 
high ; the others are 54 feet in length, the other dimensions being the same 
as in the larger tanks. These tanks may also be used for experiments with 
fresh-water fishes if desired, fresh water pipes being fitted up to them. A 
bench runs along one side and one end of the tank-house, provided with 
a central leaden gutter, and suitably sloped, an< pipes are carried over it 
to supply either sea water or fresh water to small tanks aad dishes. 
The various operations in connection with the work at the hatchery 
have been described in previous reports. Here it may be enough to say 
that the adult living plaice, from which the spawn is procured, are kept 
in the large spawning pond from year to year, their food consisting chiefly 
of mussels. The plaice which die are removed from the pond as soon as 
observed, and a fresh stock to replace those lost in this way is obtained 
each autumn by sending the attendant out on trawlers working inshore, 
who brings them in in tubs through which a current of water is 
maintained. 
When spawning begins, the eggs float in the water of the spawning 
pond, from which they are removed by a large net of mosquito netting, 
which is towed around the pond for an hour or so each day as a rule. 
The eggs are then transferred to the hatching boxes, which receive a 
supply, as copious as possible, of clean filtered sea water, until hatching 
occurs ; and when the larve have nearly, but not quite, absorbed the 
yolk they are transferred to the sea in suitable localities. 
The cost of the hatching work is small. The scientific investigations 
carried on at the laboratory require that water should be pumped regularly 
to supply the tanks, dishes, and apparatus in the tank-house, and some- 
times in the hatching room, and the only additional expense incurred in 
connection with the hatching work is for extra coal while the work is 
going on, for the assistance of a boy to help the attendant during the 
busiest weeks, and for the hire of boats to put out the fry. The total 
cost is estimated at under £100. 
The hatchery has been of great advantage in connection with the 
demonstrations to fishermen from the coast of Scotland, who come each 
spring to the laboratory for this purpose, It forms a great attraction to 
them, and enables them to form useful conceptions as to what goes on 
naturally in the sea with respect to the reproduction of-fishes, as well as 
furnishing them with specimens for the study of their development. As 
