14 
height of from twelve to fifteen feet, and so 
clear the cataract that impedes their course ; 
if they fail in their first attempt, they continue 
their efforts till they have accomplished it. 
The female is stated to hollow out a long and 
deep excavation in the gravelly bed of the river 
to receive her spawn.” * 
A similar periodical emigration has been ob- 
served in other animals, particularly in some of 
the Crustacea. 
“ Several of the crabs forsake the waters for 
a time, and return to them to cast their spawn ; 
but the most celebrated of all is that known 
by the name of land-crab, and alluded to by 
Dr. Paley as the violet-crab, and which is 
called by the French the ¢ourlourou. They are 
natives of the West Indies and South Ame- 
rica. In the rainy season, in May and June, 
their instinct impels them to seek the sea, that 
they may fulfil Ee great law of their Creator, 
and cast their spawn. They descend the moun- 
tains, which are their usual abode, in such 
numbers that the roads and woods are covered 
with them.” “They are said to halt twice every 
day, and to travel chiefly in the night. Arrived 
at the sea-shore, they are there reported to 
bathe three or four times, when retiring to the 
neighbouring plains or woods, they repose for 
some time, and then the females return to the 
water, and commit their eggs to the waves. 
This business dispatched, they endeavour to 
regain, in the same order, the country they had 
left, and by the same route, but only the most 
vigorous can reach the mountains.” + 
The object of all these migrations is, that the 
female animals may have an opportunity of de- 
positing their eggs where they will be in cireum- 
stances suited to their development, particularly 
as to the essential requisites, exposure to heat 
and to air. 
2. The same object, the choice of a suitable 
place for depositing their eggs, is accomplished 
in other instances by very different instincts im- 
planted in female animals. “ Reptiles,” says 
Kirby, “ and Fishes do not feel the instinctive 
love for their young, after birth, which is ex- 
hibited by quadrupeds and birds, but are in- 
variably instructed by the Creator to select a 
ag in which their eggs can be hatched either 
y artificial or solar heat.” Many of them 
likewise, as the salmon, dig holes before 
depositing them, for their protection. Those 
of the serpents which are not ovo-viviparous, 
bury their eggs in sand, or in heaps of fer- 
menting matter. The Saurians also select a 
TO lace for their » the crocodile, e.g. 
sagan beside IS species of sale 
mander commits a single egg to a leaf of 
Persicaria, protects it by carefully doubling the 
leaf, and then proceeding to another, repeats 
the maneuvre till her oviposition is finished. 
Toads and frogs lay their eggs in water, sur- 
rounded by a gelatinous envelope which forms 
the first nourishment of the embryo,” corres- 
ponding to the albumen of the bird’s egg. 
In iike manner every insect is directed by 
nature to place its eggs in situations where its 
* Kirby, vol. i. t Ibid. 
INSTINCT. oq 
young, when disclosed, will find its appro- 
priate nourishment; some burrowing in the 
earth for this purpose; many flies in dead 
animal matter about to putrefy; many in dif 
ferent parts of living vegetables;* bees and ants 
in the cells where they are to be fed by the 
working members of their hives, &e. A spe= 
cies of the ichneumon fly and some of the 
wasps have been observed to bury caterpi 
along with their eggs, on which their |. 
are to feed, and another fly to deposit its eggs 
on the back of a caterpillar, when the larvay 
feed on the secretion by which the covering of 
the pupa is to be formed.+ (veil 
3. The instincts called into action in the 
nidification, particularly of birds, are so nume~ 
rous, varied, and admirably adapted to 
purpose, as to have called forth admiration in all 
ages. The pairing of the parent birds at th 
beginning of spring, when the labour is to 
begin ; the choice of a: place suited to the 
habits of the species, on the ground, under 
ground, in rocks, on the edge of lakes or of 
the sea, in marshes, in bushes, on trees, on 
buildings of all descriptions; the choice of the 
materials, and the labour exerted for com- 
pleting the work ; some using clay, some sa 
some moss, some leaves, some straw or twigs : 
some moss or lichen; many forming a roug 
outside of materials hardly to be distinguishes 
from the surrounding objects, while the inside 
is warm and smooth ; some building in very pe= 
culiar forms to impede the access to their young; 
the tailor-bird sewing leaves together wit e€ 
distinct stitches, and the Java swallows forming 
their gelatinous nests, as the bees manufacture - 
their waxen cells, from the contents and secre- 
tions of their own stomachs ;—all furnish pr a 
g 
al 
of contrivance too obvious and too nez 1- 
justed to varying circumstances, to have es- 
caped the attention even of careless observers. — 
Many of the Mammalia make some kind of 
provision, although less artificial, for the re~ — 
ception of their progeny. ‘“ Cats search about 
inguisitively for a concealed situation; bur- 
rowing animals retire to the bottom of their 
burrows, and several of the Rodentia make — 
beds of their own hair to receive their young ;” — 
all beasts of prey, whose progeny come into 
the world blind and helpless, have some kind — 
of retreat in which they supply them at once 
with warmth and nourishment. Many i j 
also, besides those which associate in: hives, — 
use various precautions for the covering and pr 
tection of their eggs. 
4. The instinct of incubation, which forms: 
the next part of the provisions for the repro= 
duction of birds, the extraordinary change then 
effected in the habits of the female bird, par 
ticularly when attended and cheered, as hap= 
ns in so many cases, by the equally tempore 
foatinet of song of the vale biaeall Be 
natural phenomenon too striking and interesting’ 
to have escaped observation ; and the objectof 
* In this choice insects seem to be guided by the 
sense of smell, at least in the case where the food 
of the larve to be brought forth is different from — 
that of the parent. nen 
+ Darwin. 
via 
