New Orleans Republican. [volume] (New Orleans, La) 1867-1878, 1872-01-14
AGAsSIZ'S DISCOVERY.
Eggs and EmbryOs of the ChfrOnectes
Found Floating in n Nest.
From the New York World.

CAMBRIDGE, Mass, January 2.-Professol
I}enjamin Pierce, superintendent Of the
United States coast survey, has Just re
ceived the following letter from Professor
Agissiz, director of the Hassler expedition
detailing the important discovery which he
has made while steaning in the gulf stream:
ST. THOMAS, December Is, 1871.
MY DEAR PROFEssOR-FOr several DAYS
after we lett Boston l was greatly troubled
by sense of general weakness. so much so
that more than once thought had under
" IN more than had strength for. But as
ohm tas we got into warmer ATTITUDES | felt
nk er, and now | am actually improving
ond my condition at the start
ts soon as we reached the gulf stream we
gan work. Indeed, POurtales organized a
rty to study the temperatures as soon as
we passed Gay Head, and he will himself re-
port his results TO you, which are quite in
terestiDg.
Ny attention was entirely turned to the
gulf weed end its inhabitants, of which we
made extensive collections. Our observa-
tons favor the view of those who believe
that the floating weed is derived from plants
torn from the rocks upon which sargassum
naturally grows. l made very simple ex-
pertinent, which seems to he to settle the
matter. Every branch of the sea weed
which is deprived OF its floats at once sinks
are not likely to be the first parts developed
from the spores. Moreover, after examining
very large quantity of the weed, | can say
that l have not seen branch, however
small, which did not exhibit distinct marks
OF having been torn from solid attach
ment.
You may hardly feel an interest in nv
geological observations, but am sure YOU
will be pleased TO learn that we had the
hast npttI .f,,n
most OF the animals Known TO inhabit the
gulf-weed. and some " hlch aid not know
to occur among them. However, the most
interesting discovery Of the voyage thus far
is the finding of net built by fish, float
ing on the broad OceGn with its live freight
On the thirteenth OF the month Mr. Mans
field, one OF the officers of the Hassler |
brought Inc ball Of gulf;weed which he
had just picked up, and which excited nv |
curiosity to the utmost. 1t was a round |
mass of sargassum, about the size of two |
fists, rolled up together. The whole con-
sisted to all appearance Of nothing but |
gulf-weed, the branches and leaves of |
which were, however, evidently knit to-
gether, and not only had balled into a
rOundish mass. for though some of the
leaves and branches hung loose from the
rest, it became at once visible that the bulk
of the ball was held together by threads
trending IN every direction among the sea-
weeds, as if a couple of handstul of
branches OF sargassum had been rolled to-
gether with elastic threads trending in
every direction. Put back into a large
bowl OF water, 1t became apparent that this
mass of sea-weeds was nest, tie central
part OF which was more closely bound up
together in the form Of a ball, with several
loose branches extending in various di-
rections, by which the whole was kent
floating.
A more careful examination very soon re-
vealed the fact that the elastic threads
which held the gult-weed together were
beaded at intervals, some times two or
three beads being close together, or bunch
of them hanging from the same cluster of
or they were more rarely scattered
at greater distance one from the other
Nowhere was there much regularity OBJ
servable in the distribution of the beads,
and they were found scattered throughout
the whole ball of sea-Ne eds pretty uni
rOrmly. The beads themselves were about
the size of an ordinary pins head. We had,
no doubt. nest before us of the most curl
DNs kind, 1ull OF eggs, too, and the eggs
throughout the mass of the nest,
md not placed together in cavity OF the |
whole structure.
What animal could have built this sim
,ular nest was the next question. 1t did
lot take much time to ascertain the class of |
he animal kingdom to which it belongs
common pocket lens at once revealed
wO large eyes upon the side of the head
and a tail bent over the back of the body,
rs the embryo uniformly appears in ordi-
nary fishes shortly before the period of
The many empty egg cases OBJ
erved III the nest gave promise of an early
opportunity OF seeing some embryOs free /
ny themselves from their envelope Mean
While number OF these eggs with live
mbryOs were cut out of the nest and
,laced in separate glass jars to multiply I
he chances of preserving them, while the |
lest as q whole was secured in alcohol as q
memorial of our unexpected discovery
The next day found two embryos in one J
f my glass jars; they occasionally moved
q Jerks and then rested for long while =
lotionless upon the bottom of the jar. On
he third day had over dozen of these
Dung fishes in my rack, the oldest of which
egin to be more active and promise to at
ord further opportunities for study. | .
eed not relate in detail the evidences |
Don obtained that these embryos were ,
shes. Suffice it to say that the dorsal cord ""
18th its heterocercal bent was readily visi- :
lie, as well aa the caudal fin with its rays.
a the eyes the colobOma had not yet been
,lly closed, and blood currents were I'M
istakable about the yOlk bag. But what
ind of fish was thisi About the time of ii
,tching the fins of this class OF animals i,
fer too much from those of the adult, and -
10 general form exhibits too few PECULIAR -
"a to afford any clue to this problem. l
uld only suppose that it would likely "
owe 10 be one of the pelagio species OF the a,
lantic, and of these the most common are
ocoetus, nxucrates, scOpelus, chronicles,
gnetLus, monacanthus, tetraodon and e.