Year: 1867

An Interesting Lecture bv Professor Louis
Agassiz.


Last evening the hall Of the Cooper Institute was
well filed the occasion Of the fourth lecture deliv
cred by Professor Louis Agassz and entitled the
aquatic Animals Of the Amazon This valuable
series OF discourses the Amazonan region OF South
America with all its beauty and variety Of vegetation
wealth Of mineral and novel characteristics of
geological structure and animal life, given under the
auspices Of the Association for the Advancement
Science and Arn and creditably the popular taste
and judgment, duly appreciated by the citizens OF
this city, The recent tour Of Professor Agassiz in Brazil
and his distinguished talents naturalist which have
been brought 10 bear upon the points Of interest in that
vast region entte his observations and reflections to
moro than ordinary consideration. Tho following is
full report OF his lecture last evening


LADIES GESrLEKS:-The aquatic population Of
any extensive fresh basin has points OF
interest We may, in the first place. view II with refer
the structure Of these animals compared with


o. aea OF IS n a
contrasted with those which inhabt the sea or land we
also examine them with reference to their variety
and diversity which them under appar
emily identical circumstances And this last point is one
Of peculiar interest For you will perceive, that u ex
ing about the variety Of living beings which we find
everywhere the surfacs Of the earth we should ex
together under Identical circumsances shut out
from the influences OF the great changes


are .s s apsa sss N o os n
which are found along the seashores and circumscrbed
within the limits Of plain Of very similar condition
should expect to find great similarity Now, the
Amazon above all rivers the earth presents variety
Of organized beings which stupendous which exhausts
all conception and which was matter Il surprise even
TO me- who have devoted my life chiefly TO the study Of
fishes will therefore, try to give you some idea OF


to Won. suddenly. the interest which have felt ali the
time in these animals Not unnierestng In their ways
they have generally been neglected Few naluralsts
you will find my lecture rather monotonous And
vet if you will for a moment consider that
knowledge OF these beings has an immediate bearing
upon some Of the most important questions which
are now under consideration among naturalsts hope
about 70 submit to you. lAppause) Az frs let say


few words concerning the structure OF aquatic animals
In the infancy Of our science animals were c'assed
ditions under which they are found In nature and II
you the leaves Of the great naturasts Of the
sixteenth century, yOu will hnd that their descriptions
Of the animals then known are arranged under few
heads embracing the aquatic animals the other the
or fyine animals Bo. in proportion as our information
Of the structure Of all these beings has been growing
has been found that these 40 90. 20
have the habaton and which have the closest re-
seDblance And no longer surprised pow 70 nd IN
the water animals OF the most diversified classes, and
TO find the same diversity among those which inhabt
either the land live In the air has been
the result Of modern Investigations TO discover that ami


mails however numerous however varied are. after ALL
built upon four plans Of structure only All these plans





these structures NAV be expressed in formula so simple
that yon will permit me TO call your attention ior
moment 70 that point There are animals wn,cI nave
that is, they are radatiDg In structure And ngure
like this illustrating on the bsckboard] can oe con-
sdered as formula expressing those peculiarties OF
structure Suppose that any kind OF organ tho stomach
for instance consider. Il will be found to have
Eve pouches radiating in nve different directions Sup
pose we examine the nervous system; will be found
10 consist Of threads extending in the same directions with
the Eve rays Of the Eve pouches Of the stomach and
fha 6ua direction:
maybe the end Of each Of these threads thcre s an
eye 0yaries win be arranged in the same manner-a
and another there. and another there. THUS
tratine.J And ali these rays arc arranged around
wheel. They are rays around . vertical axis
and in that axis have the mouth at the centre 90
nsss 2 neo W. o soa
in the Amazon. We do NOT md any m fresh waters.
except only the simplest kind Of polypths fresh water
innumerable representatives In every ocean-Gch as
the ss, sea sea - and a G have existed NOT only a
All times during geological periods anterior
ocean but which have no single representative land
and but few very small ones in the fresh waters OF the


.n.s bs which is
metrca the parts Of which are arranged upon the Two
sides Of longitudinal axis 90 that these an animals have
and below. This Is not the case with these animals
You cannot call this front and this behind because these



you have no right or left; for II you call this front


lustrating) this may be right and this may be left but
So that you have TO introduce arbitrary considera-
tons You would describe these radated animals
win % 70 ana sve
which determine ther relation, their symmetry, and Ak
the position Of their parts in the manner which enables
distinguish the anterior head end and the poste
rior tail end we'll rs the right and left and above
and below To this group Of animals belong all the shell
fishes, the CLANS oysters and the Ike, snas cutie
fnnaDft1ng
and part Of them fresh water others are terrestrial
structure inhabtng the different elements which wero
made In the infancy OF our science the foundation for
the classification Of the whole animal kingdom OF this
and although I shall refer presently, Is we
have opportunity Of reference, 70 this type
among the fresh water animals Of the Amazon, let me
say that the majority Of those which have two valves
either fresh water marine The greater part
which have ony ope valve and are 1ensrsv wound
In spras We have also majority in the bnt some


IN fresh waters and some on land OF the cuttle FISH
class there are none in fresh waters-none that
terrestrial All OF them are marine and they have been


inhabitants Of globe from the very earliest periods
OF the earths history during which animals have lived
al all may repeat the Formulas OF these animals in
this way Tho anterior end marked by some prominent


feature -sch S.ss nd,eaes @ something q head No.
from the posterior There Ia longitudinal sxs the
side Of which the organs are arranged For instance in
the oyster you all know that there n pair OF gs on
each sde so that the respiratory organs placed
the right and the left while about the sdes Of the
uVusn hht AppenuARee aiu VI WHICH
these animals introduce the food into their moutha
And the ovarcs ntesnes respiratory organs and organs
OF circulation clustered in the centre. Now, the
manner in which these several parts formed and ad
justed 70 each other characterzes the different families,
different genera and different species Then We have
another group which called dyicuass-animals the
body Of which may be compared TO cylinder to tube,
. tube divided into number Of rings movable ono |
upon the other 20 that in faN the body |
Is an arcuated cylinder, containing angle cavity In
which arranged all the organs Suppose represent
that IN this way. lllustrangl These transverse rings
in this manner and the internal organs arranged in the
interior Draw line through the centre and the or
gans OF circulation are In the upper pan, the
system mainly in the lower part the respiratory organs
on the side Annexed TO these rings frequently To-
comoiive appendages In the shape OF limbs which may
be mere hooks, Is IN worms, may be artcuated |
limbs as in crabs lobsters insects and the like Now
these arcuated animals embrace also several classes,
the lowest Of which that Of the worm of which there
are marine kinds, fresh water kinds and terrestrial
kinds. Worms are found everywhere they are found
as parasee In the bodies of other animals and In the


crnal organs OF other living beings hey appear In the
fresh and salt waters and they found also IN the
earth, burrowinr under ground. Then have the |