50 
THE NEW YORK AQUARIUM JOURNAL. 
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that in other animals. You will discover this 
by looking occasionally at the skeleton of a 
bat. Besides the claws just mentioned there 
are two other claws on each side of the wing, 
a larger one at the far projecting thumb and 
a smaller one at the index or fore finger, both 
of them used for climbing. It is remarkable 
that some birds exhibit similar formations; 
as, for instance, a large kind of long-legged 
South American Wader, the Aniuma, as the 
Brazilians call it (Palameclea cornata ), which 
has strong horny sheaths covering the tips of 
two fingers, far projecting at the wrist of the 
wing, and used as effective weapons. 
But now examine the wing itself, or rather 
the soft skin forming its principal part. If 
you could touch it you would find it to be of 
extreme tenderness, yet tenacious and elastic 
like India rubber, and soft and warm like the 
most delicate human skin. It has been found 
out by recent investigations that these skinny 
wings not only perform the function of Hying, 
but constitute the largest and most sensitive 
organ of touch which is to be found in na¬ 
ture. It has numerous tender nerves, ending 
in thousands of peculiar organs which closely 
underlie the roots of the delicate hairs spread 
all over the skin. By means of this great 
number of organs of touch the animal is sen¬ 
sitive to the gentlest motion of the air, and is 
thus actually able to “feel” a body while it 
is still a foot distant. This explains why bats 
never fly against windows like birds or insects 
—why blind animals find their way about just 
as well as seeing ones, and how they can 
move in dark subterranean grottoes and cav¬ 
erns as well as in broad daylight. Is not this 
a most remarkable peculiarity? We have 
here one of the great marvels of nature—the 
utmost perfection of a sense— almost incom- 
pi ijhensioifc to our aauer»EaBuln^; ye"xt Sr 
not to be doubted, be it ever so singular, for 
it has been proved by numerous experiences, 
just as firmly as the utmost sharpness of a 
dog’s power of smelling, which is alike unat¬ 
tainable to our faculties. 
The body of the hlying Fox is covered by 
soft, woolly hair, of an agreeable brown and 
yellow color. The elegantly shaped head has 
moderately long ruffled ears, brisk eyes and 
an acute muzzle, resembling the head of a 
neat Italian greyhound ; hence the name. 
It is very interesting to see the animals 
feed. The solid food, consisting of fruit, 
boiled nee or tender meat, is taken by one of 
the hind feet and the claw of one thumb, 
brought into convenient position and, half 
pidden by the wing, hanging on the other 
foot they devour and press it, so to speak, 
into the upper regions. Every rule of nature 
seems to be set at defiance. They are very 
fond of water, fight with a clattering noise 
for it, and lap it with their extremely long 
and thin tongue. 
Flying Foxes are perfectly harmless crea¬ 
tures, feeding in their natural state on fruit 
and insects, and having in this respect noth¬ 
ing in common with the abominable blood¬ 
sucking vampires of South America. But in 
spite of all interesting and even handsome 
details the observer is hardly able to over¬ 
come the impression of their ugliness. We 
are too much accustomed to see beautifully- 
shaped and colored birds and insects to ap¬ 
preciate, from an exterior point of view, the 
experiment of nature to extend the body 
of a mammal to that of a bird. The mam¬ 
mal is most adapted to movements on the 
solid earth, and shows the greatest accom 
plishment of its form when • built expressly 
for this purpose ; as, for instance, in the body 
of eats or of hoofed animals, such as the an¬ 
telopes. The mammals moving in air, water 
or underground, exhibit a greater ugliness 
the more their organization makes them fit 
to live in these surroundings. 
FISH CULTURE AT THE AQUARIUM. 
The apparatus in use in the Aquarium for 
huh culture is of the latest and most approved 
pattern, and consists of a large wooden reser¬ 
voir divided lengthwise by a partition, in 
which are placed frames covered with a woolen 
screen which filters the water before it passes 
over the eggs. The hatching troughs, five in 
number, are placed with their heads abutting 
the reservoir and are supplied by brass cocks. 
In the troughs are placed frames covered 
with wire cloth, which, with the wood work, 
and in fact every part that the water comes 
in contact with, is coated with coal tar, which 
not only keeps the wire from rusting, but also 
prevents the jelly-like sap that always appears 
in new pine wood when under water, from 
exuding, while it also is a barrier to any 
vegetable growth upon it. 
of which several layers can be used in eachf 
trough, thus increasing their capacity. Two,, 
of the troughs are now filled with young of 
the California Salmon from three to five 
weeks old which were hatched where they 
now lie, from eggs which were presented by 
Prof. S. F. Baird, the Commissioner on Fish¬ 
eries for the United States. They were ob¬ 
tained from his Salmon breeding ranch 
on the McCloud Biver, California, in charge 
of Mr. Stone, the Deputy Commissioner. 
This variety of Salmon is called by Nat¬ 
uralists the Salmo Quinnat, and from its 
being capable of passing through water 
that in Summer reaches a temperature of 80 
degrees Farenheit on its annual migration 
from the sea to its fresh water breeding 
grounds above, and which would kill its con- 
genor of the Atlantic Coast, is more valuable 
than the latter for stocking all our rivers 
south of the Connecticut. Many millions of 
the eggs have been taken, hatched and dis¬ 
tributed by Prof. Baird in the past two years, 
but as it requires three years for this fish to 
reach maturity and return to the place where 
it was deposited, it is too soon to see the re¬ 
sults yet, though many young have been 
caught during the first year that they remain 
in fresh water. 
The eggs are obtained from the living fish 
by pressure of the hand upon the abdomen, 
and such is the delicacy of touch and knowl¬ 
edge of condition acquired by an expert that 
a fish is seldom killed by them, and Mr. 
Mather states that he has taken eggs from the 
same trout for five years in succession with¬ 
out injury to them. After the eggs are taken 
in a pan that has been merely wet, a male 
fish is manipulated m the same manner over 
the eggs and in a few minutes after the addi¬ 
tion of a little water, the fecundation is com¬ 
plete and the ova is placed in a trough where 
it remains for three or four weeks, until the 
eyes can he dis tinctly seen and the unim¬ 
pregnated ones picked out, when they are 
packed in a box with a layer of fine, living 
moss, and a layer of eggs alternately until 
full—this box is then packed in a crate of hay 
or box of sawdust to keep it from changes of 
temperature and sent by express to any part 
of the world. The eggs of the California 
Salmon are the largest now handled by fish 
culturists, measuring nearly one-third of an 
inch in diameter, and as the eggs of any fish 
average about one size for each species, they 
are measured to find the number of thousands 
taken. 
It takes from forty to sixty days to hatch a 
Salmon egg, according to the temperature; a 
high one, say 70 degrees, hatchingvery quick¬ 
ly but leaving the fish weak. The best tem¬ 
perature is that of the spring water in which 
they are laid, perhaps, from 45 to 50 degrees. 
After hatching, the yolk of the egg remains 
attached to the abdomen for about thirty 
days, and at first is so large that the little 
embryo cannot swim with it, but it is gradu¬ 
ally absorbed and when all taken up the 
Salmon takes food for the first time. This 
rule is good for all the varieties of Salmon 
and Trout. Some fish, as the Whitefish and 
Shad, can swim as soon as hatched, although 
the sac is attached in the same manner. 
Another trough contains 25,000 eggs of the 
Lake Whitefish, and 15,000 eggs of the Cisco 
or fresh water Herring, which were presented 
by Mr. Geo. Clark, one of the Michigan Fish 
Commissioners, and a recent addition of the 
eggs of Whitefish, Lake, and Brook trout 
from Mr. Seth Green, Superintendent of 
Fisheries for New York, has been made, to be 
followed in February by the Land Locked Sal¬ 
mon from Maine, the gift of Prof. Baird ; these 
are ail winter-spawning fish and hatch slowly 
on the trays. Shad eggs require an entirely 
different treatment, which will be explained 
in a future number of the Journal. It is the 
intention of the Manager of the Aquarium to 
stock some of the rivers with the fish hatched 
here, thus making it useful as well as in¬ 
structive, and a valuable adjunct to the Fish 
Commission, and to this end he has engaged 
the services of the well-known Fish Culturist, 
Mr. Fred. Mather, to superintend this Depart¬ 
ment, for which he is well qualified by his long 
experience as a breeder of trout for a long 
period at Honeoye Falls, N. Y., and his work 
of Salmon and Shad hatching for the past 
three years for the Virginia, and United 
States Fish Commissions. 
This is one of the most interesting features 
of the Aquarium, both to the Naturalist, the 
Embryologist, and the casual visitor. The 
newly-hatched fish is so transparent that the 
beating of the heart and circulation of the 
blood can be seen with the naked eye, and the 
development from the embryo to the perfect 
fish observed from day to day, and a wonder¬ 
ful transformation it is, for at first the little 
creature is as unlike the parent fish as a tad¬ 
pole is unlike a frog ; the mouth which at 
first is only fitted to pass water to the gills is 
changed so as to take food, and the embryonic 
fin which, rising in the middle of the back, 
runs around the tail to the anal fin, is ab¬ 
sorbed, leaving the true fins more and more 
distinct each day. A few years ago Prof. 
Agassiz discovered that the Salmon had a 
second heart situated in its tail which was 
most visible at the third day and disappeared 
about the tenth. 
It is expected that Salmon will be ready to 
take food at about six weeks old when the 
sac will have been entirely absorbed; they 
will then be in condition to find their own 
living in the streams if put in such spring 
creeks as are chosen by the parent fish as a 
place of deposit the. eggs. 
