48 THE; N£W YORK AQUARIUM JOURNAL. 
KISH CULTURE AT THE AQUARIUM. 
The apparatus in use in the Aquarium for 
full 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 
i n 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. _ f _ __ \ 
The eggs are laid upon these wire screens, 
of which several layers can be used in each 
trough, thus increasing their capacity. Two 
of the troughs are row 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. P. Baird, the Commissioner on Fish¬ 
eries for the United States. They were ob¬ 
tained from his Salmon breeding ranch 
on the McCloud River, California, in charge 
of Mr. Stone, the Deputy Commissioner. 
This variety of Salmon is called by Nat¬ 
uralists the Salmo Quinnat, and Rom 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 tbe Connecticut. Many millions of 
the eggs have been taken, Patched and dis¬ 
tributed 1 y 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, 
aud 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 in 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 be distincily seen and all 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, hatching very 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 hatchiug, 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 T -out. Som 3 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 
bv Mr. Geo. Clabk, one of the Michigan Fish 
Commissioners, and a recent addition of the 
eggs of Whitefish, Lake, and Brook trout 
from Mr. Seth Geeen, 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 all winter-spawning fiSh auffhatch slowly 
on the trays. Shad eggs require an entirely 
different treatment, which will be explained 
in a future numb or of the Journal. It is the 
intention of the Manager of the A quarium 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 
S ates 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 tue heart aud 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 (.lay, 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 xnly fitted to pass water to the gills is 
changed so as to take food, and the embryonic 
fin which, rising in the middle ox 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 for the eggs. 
THE TWIN SALMON. 
The Twin Salmon or “ salmonese twins” as 
the aquarium wag has christened them, are 
among the most interesting objects now dis¬ 
played in Mr. Mather’s department. The 
above illustration taken directly from the life is a 
careful representation of these queer little crea¬ 
tures as they now appear, under the magnifying 
glass. The two bodies are attached to one sac, 
but each fish is perfect in itself. The con¬ 
necting vesicle is filled with oil globules, arteries 
and veins, and it was expected that a microscopic 
examination would discover a diaphragm sepa¬ 
rating the circuladon into two distinct systems. 
The closest scrutiny, however, fails to discover 
this wall and the circulatory systems appear so 
intimately connected that the blood flows freely 
from one body to the other, impelled, however, 
by two hearts. 
_From the extende d obse rvations of Mr. Ma¬ 
ther, it appears that these deformities~are quite 
frequent in the salmon family, which includes the 
trout, and in hatching one hundred thousand 
eggs, there may be from three to five hundred ab¬ 
normal specimens, comprising crooked backs, 
twisted heads and tails, and in some instances 
two or even three heads are attached to one body. 
THE SEA RAVEN. 
Hemitnpterus Americanus. 
Closely connected by family ties to the Sea 
Swallow, is the Sea Raven, a fine specimen 
of which may be seen in table tank 4, and it is 
always surrounded by doubtful admirers who 
speculate as to the ownership of the wonderful 
tufts, “bobs,” and masses of disjointed flesh that 
seem to cover it, and the visitor is not rarely 
led to believe that by a system of inactivity it 
has been covered with a growth of aquatic 
plants and verdure. But they are all “ real,” 
and this fantastic ornamentation is the bona- 
fide work of nature. It is subject to great 
variation of color, and the Aquarium will soon 
possess specimens, varying from the rich, rus¬ 
set brown to a bright carmine yellow and red. 
