197 
- were placed in a glass tank, and one morning he saw a mass of 
ova, about eight inches long, four wide, and from one-half to 
three-fourths of an inch thick, at the bottom of the aquarium. 
One of the parents hovered over the eggs, fanning them with 
its fins, and this fish subsequently proved to be the male. The 
young hatched in from six to eight days, the female taking no 
‘notice either of the eggs or of the young. These eggs, each of 
which was about one-sixth of an inch in diameter (after it had 
become distended with water) were adherent, but not enveloped 
with glutinous material, so that lying loosely, like a pile of 
shot, they were conveniently placed for aération by the efforts 
of the male. An experiment was now tried of taking some of 
the eggs from the mass, which were placed by themselves, but 
‘none hatched, showing that aération, as carried on by the male, 
‘is necessary for their development, and even the young were 
similarly fanned until they began to feed, which was about the 
fourteenth day after hatching. 
The sticklebacks or pricklebacks of this country, whether 
marine or fresh-water species, form a nest for the reception of 
t heir eggs, which has an entrance on one side, an exit on the 
other, so that either parent can readily pass through. When 
the eggs have been safely deposited in the nest, and the neces- 
sary fertilisation accomplished, the male takes charge, driving 
his helpmate off to a safe distance, in order to prevent her 
naking a meal of the ova. Mr Warrineton ascertained that 
in a few days, in the fresh-water species, the nest was more 
and more opened by the male, evidently owing to the necessity 
for oxygenation, and he hovered over it, causing a current of 
water to be propelled across its surface by fanning it with his fins, 
and after about ten days the nest is destroyed, and minute fry 
ppear, over which the male keeps guard. Some of our marine 
wrasses of the genus Orenilabrus have been observed to con- 
str uct nests, in which occupation both sexes assist. The river 
bullhead (Cottus gobio) forms a hole in the gravel at the bottom 
stream, and here it keeps guard over its eggs as well as 
infant progeny. 
In India are several species of the amphibious snake-headed 
