VEPvTEBKATA. 
1 
this economy of the nature of these animals, the eggs of the female heing taten to any desired 
locality and placed in the water, and strown "with the milt of the males. 
At the season for depositing the spawn, which varies with almost erery genus, some species 
repair to the gravelly shallows of rivers, and others to the sandy bays of the sea. This move- 
ment is called by fishermen "going to hi 11,^'' or "roading other species resort to bunches of 
weeds. The object of that remarkable instinct in fishes which induces many species, as the her- 
rings, pilchards, mackerel, (fee, to peiform long migrations, is doubtless to secure proper places 
in which to deposit their spawn. The shad tlms ascends our rivers in the spring, and the salmon 
in like manner not only passes up the streams, but often, with an astonishing perseverance and 
vigor, shoots up cascades and waterfalls which might he supposed to present insuperable 
obstacles. 
In many instances, when ready to deposit her spawn, a female is accompanied by two males, 
one on each side — a provision of nature Avhich seems intended to secure the impregnation of the 
largest quantity of ova ; and beside, the range of the influence of the male fluid is enormously in- 
creased by diffusion in water. The adhesiv^e nature of the surface of each egg supplies the means 
of attachment to any of the various substances near which it may happen to be left; the time 
required for the appearance of the young fish is very variable, depending upon the species, and the 
season and its temperature. The young fish is first apparent as a line wound round the central 
vitelline portion of the egg, and ultimately escapes by rupturing the external capsule with its 
tail. The spawning appears to take place only once a year. Many fishes, however, are what is 
called ovo-viviparous ; that is to say, the ova are retained within the oviduct until the complete 
evolution of the einbryo. Tbe 
mode in which the impregnation 
of the ova is effected in these cases 
is not exactly known. Fishes ap- 
pear always to select shallow water 
for the deposition of their ova ; but 
beyond this they do not generally 
'! exhibit any care for their oflfepring- 
ij A tew, however, form a sort of nest 
i for the protection of their eggs and 
young ; and in some instances, the 
male remains as a guard over the 
fiy until they have acquired suffi- 
cient strength and agility to ven- 
ture forth into the Avorld. The 
little sticklebacks, common in 
ponds, furnish an interesting ex- 
ample of the exercise of this in- 
stinct. Similar instances of care 
for the place where the ova are de- 
posited are furnished by the Eu- 
ropean river bull-head and the 
lump-sucker. Instances of attach- 
ment between the parent fishes are 
also known among a few species. 
The number of fishes in the va- 
rious waters of the earth surj^asscs 
all human conception. Every pond, 
stream, river, and lake, as well as the ocean, covering three-fourths of the surface of our globe, 
swarms with these creatures. Such are the provisions of nature to maintain and multiply 
fishes, that streams which are dried up during the hot season are soon after supplied with abund- 
ance of these creatures, owing, no doubt, to the hatching of eggs which have been deposited in 
m 
NEST OF STICKLEBACKS. 
