of the Fishery Board for Scotland. 177 
tank was increased, but it was judged that that would not suffice, and the 
blackened parts of the spawn were torn off, the portions that seemed in 
good condition being replaced in their old position. The spell, however, 
was broken. The male did not resume his attention to the eggs, the mass 
of which was indeed much broken up and diminished in size. He pushed 
some of the pieces about the tank and withdrew. Both he and the eggs 
were placed in another tank, without any better result. He pushed the 
pieces about a little and left them. And when the other male was 
introduced, he seemed oblivious to its presence ; his animosity, at first 
associated no doubt with reproduction and fertilisation, and then with the 
care of the eggs, had quite departed. 
On examining the portions of the egg masses that remained, the surface 
was found to be flocculent from the empty egg-shells from which the 
young fishes had escaped, most of which were still attached to it. On 
the other hand, the interior of the mass was solid, the eggs all containing 
embryos, some of which had died, but many were subsequently hatched 
out in jars. From an early pericd some of the eggs, but not many, next 
the glass in front of the tank, were observed to be white and opaque 
(dead), but they did not decay. 
The difficulty of hatching the eggs of the lumpsucker was pointed out 
previously by M‘Intosh, who stated that in tanks they speedily acquire a 
fetid odour, that the death of a few causes putrefaction of the whole, and 
that they had not yet been hatched out in tanks.* He does not give any 
particulars as to the dimensions of the tanks or the flow of water, but 
probably the chief difference between his experiments and that described 
here was that the male in the latter case was constantly engaged in tending 
the eggs, which shows how efficient that attention may be. 
The hatching of the eggs, so far as it was accomplished in the tank 
under the care of the male, extended from the 5th to the 22nd of May, 
or seventeen days. The greater number were still unhatched on the 
latter date. It seems a long period, considering that the eggs were 
deposited, and no doubt fertilised, at practically the same time. Under 
natural circumstances, it is probable that the time taken for the hatching 
of all the eggs is prolonged, for it is difficult to understand how the larve 
could make their way from the interior of the mass by the narrow channels 
between the eggs if the eggs there were hatched as soon as those on the 
exterior. The condition of the masses shows that this does not occur, and 
that hatching proceeds from the outer surface inwards, a process which must 
take a considerable time. It seems very likely that the development of the 
eggs towards the centre of the mass is retarded, owing to defective or 
inferior aération there, compared with the eggs on the surface and near it ; 
and that this is related to the gradual disintegration of the outer surface 
as the eggs hatch there, and a pathway of escape is opened to the larve. 
One could not fail to be impressed with the advantage to the species 
of this guardianship of the eggs by the male fish. Numerous foes must 
be driven off and the eggs preserved, and I do not think the story of 
Fabricius, that the lumpsucker under such circumstances will attack the 
wolf-fish, need be doubted. The courage and pugnacity of this usually 
docile and inoffensive fish seem boundless when it is protecting its eggs, 
and in contests of this kind it not infrequently happens that courage and 
determination count for as much as strength and the power of inflicting 
real injury. 
The conclusions from the experiment may be thus summarised :— 
(1) The male alone defends the eggs, the female taking no part 
whatever in protecting them, 
*Annual Reports Vishery Board for Scotland, 3rd, p. 60; 14th, p. 272. 
M 
