The Bolivar bulletin. [volume] (Bolivar, Hardeman County, Tenn.) 1865-1888, 1872-02-09
Professor Agassiz's Marine InTesti-
cations.

6aNAOAos
The following interesting letter,
written by Professor Agassiz on
board the coast-suryey steamer dass-
Ter, has been received by Professor
Benjamin Pierce, superintendent of
the coast-surVey
ST. THOMAS, Dec. I5, 1871.
1fy Dear Professor For several |
days after we left Boston I was great /
ly troubled by 8 sense of general |
weakness, so much so that more than |
once l thought I had undertaken |
more than had strength for. But |
as soon as we got into warmer lati- |
tudes / felt better, and now I am |
actually improving beyond my con-
dition at the start. AS soon as we |
reached the Gulf Stream We began |
work, Indeed PouFtales organized a |
party to study the temperatures as
soon as we passed Gay Head, and he
will himself report his results to
you, which are quite interesting.
My attention was entirely turned to
the gulf weed and its inhabitants, o
which we made extensive collec
tions. Our observations favor the
views of those who believe that the
floating weed is derived from plants
torn from the rocks upon which sar-
gassum naturally grows. / made
very simple experiment which seems
te me 20 settle the matter. Every
branch of tue sea-weed which is de-
pTiVed Of its floats at once sinks to
the bottom of the water, and these
floats are not likely to be the first
cute 1.rrnTrve@6
Moreover, after examing q very large
quantity OF the weed, l can say that
l have not seen a branch however
small which did not exhibit distinct
marks of having been torn from
solid attachment
You may hardly feel an interest IL
my geological observations, but l am
sure you will be pleased to learn that
we had the best opportunity Of care
fully examining most of the animals
known to inbabit the gulf-weed, and
some which l did moi know to occur
among them. However, the most
| interesting discovery OF the voyage
thus far is the finding of 3 nest built
| by fish, floating on the broad ocean
| with its live freight. On the 18th OF
| the month Mr.. Mansfield, one of the
| officers of the HassleF, brought me a
ball of guIf-weed which he had just
picked up, and which excited my Gu
| riosity to the utmost. 1t was round
mass of sargassum, about the size OF
two fists, rolled up together. The
| whole consisted to ali appearance of
| nothing but gult-weed, the branches
and leaves of which were, however,
evidently knit together and not only
| balled into q 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 trendiBg in every direction
| among the sea-weeds, as if a couple
of handfuIs of branches of sargas-
sum had been rolled up together
with elastic threads trending in every
direction. Put back into a large
bowl of water it became apparent
that this mass of sea-weeds was a
nest, the central part of which was
more closely bound up together in
the form of ball with several loose
branches extending in various direc-
tons, by which the whole was kept
floating.
A more careful examination re-
vealed the fact that the elastic threads
which held the gulf-weed together
| were beaded at intervals, sometimes
two or three beads being close to-
| gether,. or a bunch of them hanging
| from the same cluster of threads, or
they were more rarely scattered at q
| greater distance one from the other.
Nowhere was there much regularity
obst rvable in the distribution of the
| beads and they were found scattered
throughout the whole ball of sea-
weeds pretty uniformly. The beads
| themselves were about the size of an
ordinary pins head. We had, no
doubt, a nest before us of the most
curious kind, full of eggs too, and the
eggs scattered throughout the mass
Of the nest and placed together in a
cavity of the whole structure.
What animal could have built this
singular nest, was the next question.
It did not take much time to ascer-
tain the class of theaRimsl kingdom
to which it belongs. a common
pocket lens at once revealed two
| large eyes upon the side of tbs head
and a tail bent over the back of
the body, as the embryo uniformly
appears in ordinary fishes shortly be-
| fore the period of Matching. The many
empty egg cases observed in the nest
gave promise of an early opportunity
of seeing some embryos freeing
themselves from their envelope.
| Meanwhile a number of these eggs
with live embryos were cut out Ofthe
nest and placed in separate glass jars
to multiply the chances of preserv-
ing them, while the nest as a whole
was secured in alcohol as q memorial
of our unexpected discovery.
The next day l found two embry os
in one of my glass jars; they Occa-
sionally moved in jerks and then
rested for a long while notion
less upon the bottom of the jar. On
the third day / had over a dozen of
these young fishes in my rack, the
oldest of which begin to be more
active and promise to afford further
opportunity for study. / need not
| relate in details the evidences l soon
obtained that these embryos were
! fishes. Suffice it to say that the
dorsal cord with its heterocercaI
! bent was readily visible, as well as
the caudal fin with its rays. In the
eyes the coloboma had not yet been
fully closed, and blood currents were
unmistakabie on the yolk bag. But
what kind of fish was this About
the time of Matching the fms of this
class Of animals differ too much from
those of the adult, and the general
form exhibits too few peculiarities,
to afford any clew to this problem. l
/ conld only suppose that it would like
| ly prove to be one of the pelagie spe-
cies of the Atlantic, and of these the
| most common are exOcoetus, naucra-
ties, scopelus, chiroHectes, syBgnethus,
| monacanthus. tetraodon, and dioden.