, 1864-02-12
STRUCTURAL ZOOLOGY.
Professor Agassiz at Bryan Hall.
Tho Animal KfDsdom-Its Types-
Four Leading. and Fundn-
mental Ideas.

The second lecture OF the course delivered by
Prof. Louis Agasziz, before tho Young Mems Asso-
cial1on was given In Bryan Hall LAST evening. Tho
ball was comfortably filed, aud the lecture WAS
q auch more interesting one to the popular mind
than the frxt. Most of ns have acquired some
faint Idea OF geological distributions and VIC are
always most interested when We understand q lit
tie cf the general scope OF the subject beforehand
The eGhject was The Structure Of the Animal
Kingdom which the professor handled with his
well known ability. While in the treatment Of
his rubjec: he showed himself to DO an accomp-
1ished "Natural Historinn," In Its clucidatlon ho
betrayed a good acquaintance with Geology, ca-
pccinlly with the chalk formation. In his fingers
the little piece Of chalk assumed magic power
and the picture grew out on tho blackboard al
most Gs II by cuclantment. And not only could
be By two or three master strokes evoke an un-
m1stakable likeness Of an object, but his
lines were l1otean In their proportions.
The eame line which gaze the
''fornand ttature'' Of the mussel formed the
base Of q anails profile. The mutation Of a wasp
inte graeshoppcr WIS effected by three move
mcnts Of the hand, SO rapidly executed that the
iugglers ski1l-could not have surpassed 1t, while
the I'm Of q fish and the human hand showed uu-
der his challiugs cloeeness OF resemblance Of
which thuse IN the hAll had never discerned, nor
could have conceived even from the lecturers
lucid description, If unaccompan1ed by his Illus.
.ratire drawings.
The following Is the thread Of his discourse:
From the beginning Of antiquity the chief efforts
Of students in the animal doaIn Waa fo trac,. nnt
a continuous chain Of deycIopment: Int tha ~.
searches Of The modcrns have shown that anIuals
arc grouped only, contrary to the original idea of
luis direction by Cuyier when hn 6,srnvcra tat ~
anInisle are bnilt on four pians. and th.t ihc1o @
were but four distinct plans ID lie ani1aa, inr. @
before been made. >'4ee''e'' 'D'A ua' e'ef
An idea OF what these relations ore NAV In eath.
s5sd from view q ihe endless disersfy Of 7srIa-
one ibrmc-eo dtreIso hat Ike nnstiatod amy oar
may rot be able to distinguish lie ssmfar1tTl
Ihs,G are o15 ,anss e. in Witch 9s ceso5
q abe1 neso s ~ foax
that they cannot be transmitted; philosophical
As 1epfeecnta:Iycs of thcso erouns wa NAV n,r,a
several individuals. Tho 7adfain nre nfran~r,]
with e1mmesr,cal identity Of parts which radIate
but with ihe most minute and an interior s' psrts,
Ever, wtclo the great idea Of radiation around the
s seR ,at & a2d
sense OF the Term Indeed, they arc 70
much arranged aronnd an aka that they were
thai they really arc g. but that ther external form
appre1imatss closely 70 tho regularity Of tho dis
&c & snas sd sa seo thy u
have regularly developed nervous organ,zalon.
The stnefnl PUN oi the ..1adia,a'' may be repre-.
&C., ssntSd hy - Some 81 M them ars merely ssc-llke
obte1Iabc. The lecturer here gave Illustrations on
ilo blackboard, showing the difference in structure
nnd tie den, orders Of 5adaa he
E:oWth, Developed into the aower like animal.
The jelly-feh wins sample Of another form Of the
same t.,ps grfai idea. ssn,i E'obgar mass In which
s1es ten,selss pe1pend rom @ The sss,F n!s esr rRg.
Tie walls Of ,te sac are thin and
Ecn, but there is no mere difference
he1Wt en- these two orders than the building oftwo
houses on TIC eaEae plan, but one OF brick, the
4f hss op The des s,
another example, whose exterior sac Is dotted
with Fymmctr3c:lly placed holes from which spring
dent, with walls OF their own but still built on the
1adtated principle. There arc here three especially
DISTINCT structures. yet the eamc plan carrled out
ucde1me. S~.'f's' A>f1' 'Do '."''
Tie rext primary division Is that Of the Mol
luses, called 60 on account Of their general fca-
they diner e@ Inc % st clsss baTe
Ills is 10, the case with tho fadiate. We havs
lion weh dctctmles symmctfy In thc arstnr pgs
We have fhe Int shcil on he rIcht side the cnn
cave one ON the len nni fhe rnnnth In
ton oa ha dhe saes ths ea1ss aro thrown
hesd OF back: hence II We would ~. n1,nins ins
this case Of animals Nc must pace % them On theIp
ceesiye laye,e. Il ,s \ ihicteneI erJ5o5, =, eoC
Which the mantle is the skin or dcrm{ss Th9s IL
ses y Ma 70 nnge hlsh M ndef the
Keen in nernctnaf mnttnn iurin1 ;bo MatSa " ~
animal and Eeeps up Tie current which snonfies NJ as
t vith water. The lecturer then gave diaggran g
frince of the nyster shox2np 1he srmmetr,ca, ~
laflon Of lie parts to each other.
as exhibiting araalta difference in structure. Tie
shown to be built on thc same eienenarT modai naI
as thc oyster, with differences onir Of iefo,, E1
aetly re Is same me strnctprea Is seen IN the
c1asses Or aT7ers oS rnollu.1s aa,1 1"o eftat
SaITes and lie ~ ~ aeSepaa'a OF o.
on1n TI, SSu Iae sntue-nsa gt ccphal'
olTna lTia Iatse s.nos o. animals 91 one plan
ID art,cnia1, ,ha lee ene a s sinsa9m III call
oafM ocS tn 9nas.ss inclosed sy Hn:e which move on
BE- cairS out Fl eat anner 1ns eaenf hnf IL e as
., nase me =, eionsasea cylndef. The rings may be
1, , ~ aaong me oody ann pe with Or With.
a.te ont H.. he worm Or fcfmts hss the greatest
~ tha afhea,a'a hc9n N Wn!ea 5ne anterior pat q
tnec,hrr y-bf,e tbo psta.,a o. iaass soneIeo
m9yesSi WI" H. eeSerI ess nos.eiof portion my b.
i s,ei 1s q .amihaf example: Ihcn we have the
en, 3rnse .ns nao 4u ~ EoGss ta1sctsi Anssng
.tfTf,si III Uni "a .ne n1nus OF tao
haze thc craene ~ on rian ap ~ .nesa ~e
htch We r.n have M iies elcent 40 u aeaa, o.
# from tha stnlv 19x' - r. ns VIC sa.ae1
mcdr o1er,crs,o1 T., ,b | T. .nea IT, Ano.aes 1f
cs1ri7cr oa nnrer 20 + IA d-s, tiea - c tne
suoalI Difference cx1ats EetWecn fha "sr s,,d IL
grafs-toppcr TIE cLansss in nTmn3s pts4aneeS ca
uot iees TarI than ~. tho.a aii1ain.1a ftI 16e @
one radfrnt t,es ~ .his ~ 81 th ..a .o1 .5 .nd
cias.es Thia ri.ss i,so tho mo ,noaIinh, u
enhdfyidcd into tj,,ra ranar.i dr,f"ra.N4o-a 20
crnstaees Hnd insecis ss'sA"1 o'"e1'-"''"''
Ii is by strdyins, t1,e sctpnce IN th,s ,r that wa
NAV Ee BE- ie 10 he na1 y hnt ihe
a1.l ~ snns1 ~ ~ @ dn.snt 3 nao, Ias LIZ
as - s5cx ., ana gsonp1aas ,s
piyipr comDreheusiyenesa to ia nrnta1 rrssn Ian
which could hot well he ntherwiee affaincds TX
college and Echool Of thc land these sfnins Son11
be introduced. ard become a part Of the eiucafinn
Of every one.
The fourth plan Of structure Ia the most impor-
tant-ye1tebrata, Of the animals provided with
ting with man. Among them We have single
plan OF etsucture-thctc Is d solid tnternal nr5s.
radically different from the other rlnssoa ,rhich
have no internal backbone: made m Of iointe1
pieces surmountcd By solid arch. another solid
arch below. In the upner cavity Il minced ali
those portions ard orrnns which bItnn tbe atsnc.nra
into relation with external obiects In Ike in.7er
are D'nred the nr~sna ri snnn1rt T1hasa 90 ~
cred with a f1eehT mass whirf Il itaeiY 1nvernd
with hair, horn, or feathers. All the animafs of
this class are easily TRANSMITTED into each other;
IL .heH Genera! affensement being the same. Take
ias ~ a,aeasnce o' eaeent,or, not q plan: Give