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H'hen on board n.. M.S. Hengle, as naturalist. I 
uch struck with certain fa.-Ls in the distril 



., ■ - .. ," — •••■ ' lo 111 Luu uisirutution of 

he „. ,l„u„u.s ot South An.erica, an.l in the ^^eolo^ica 
elafnns of the p-esent to the past inhabitants ofTha 
cont.nent I hese facts seemed* to me to throw some 
111,'ht on the orifTui of species-that mystery of mysteries 
as it^ ■ T'' ""i^'^ ^^ """^ *'^""'" ^"-eatest philosophers' 
Oil my return home, it occurred to ,ne, in Wir, thai 
.omethniK might perhaps be made out on this c.u^s on 
by patiently accumulating and reflecting on all so^ 
of tactewh.cb could possibly have any l>earin^ on U 
After hve years' work 1 allowe.l myself to speculate on 
the subject, and drew up some ^hort notL ; these I 

Hiiich then seemed to me pndmble : from that perir>d 
to the present day 1 have steadily pursued the^Jml 
object, i hope that I may be excused for er.terin^on 
these personal details, as I ^ve them to show that I 
bene not been ha,sty m coming to a decisi„„ 

,r.: L'^r .k" ""'" "*'"^>' ^"'***'*'*^ ' '"'t as it will take 

r. two or three mure years to omplete it, and a. n.y 

althis far from strong, I have been ur,.ed to publish 

to do this, as Mr. Wallace, who i« pow of.-i..:..., ^t 
natural h.story of the Malay archipelago, b'a/ "arrived 
at almost exactly the same jreneral concl 

have on the 



usions that I 

■i{»ecie«. l^uot year he sent 


me a 


memoir ou i\u> sui.|t;(t, with a reijuost that I woalii 
hirward it to >ir Charles Lyell, wlio sent it to the 
!,iiiift'-iii ^0(•iety, and it is '>hed in tlie third 
Toliiino of the JourTial of tliat Soonity. .^ir ('. I.yeil 
iiid Dr. HoolxtT, who hoth knew of my work -tlu! 
hittor havin;r r«'a<l my sketch ot i;!U hotioured me 
by thinkiii:r it Hiivi8;Ude to piihlihii. with Mr. W'alhice''* 
••xct'ilt'dt memoir, .some li.-ie .'xtraots from rny niaiiu- 

Iliis Alvstraet, whieh I now |)iil)li>h, must neces- 
sarily he imperu-ot. I cannot here pve reference< and 
authorities for my several statements ; ami 1 inust 
trust to the re^nier reposing some coiitiiUMice in my 
accuracy. No douht errors will have crept in, though 
1 hope i have always heen cautious in trusting to troctd 
authorities aiv)ne. 1 win here ^ive only the fjeneral 
conclusions at which 1 have arrived, with a few facts in 
illustration, hut which, 1 hope, in inostcaaes will suffice. 
No one can feel more sensible than I do of the nece.s.sitv 
of hereafter publishing in detail all the fact«, with 
references, on which my conclusions have been frrounded ; 
.ind I hope in a future work to do this. For 1 am well 
aware that sc^ircely a single point is discussed in this 
volume on which facts cainiot be adduced, often 
apparently leading? to conclusions directly opposite to 
those at which I have arrived. A fair result can be 
obtained only by fully stating and balancing; the facts 
and arffumeiita on both sides of each question ; and 
this cannot pofisihly l)e here done. 

I much ref,^ret that want of space nreventj^ myhavint^ 
the satisfaction of acknowledfrinjr the ^a'nerous assist- 
ance which I have received from very many naturalists, 
eome of them personally unknown to me. 1 cannot, 
however, let this opportunity pass without expressiiiji 
my deep obligations to Dr. Hooker, who for the last 
fifteen years has aided me in every possible way l»y his 
lartre stores of know led^re and his excellent judtrment. 

In couMderui:; the « >rii.nn of .>jtrcies, it is quiie c»»ii- 
ceivablo that a naturalist, retlectini; on the iiuitual 
affinities of or^^anic beings, on their embryoloirical 


relatiou^. their peotrrapbica! distril.ntion, jrfv.i.uMcal 
*uccesH,on, a,.d other .uch tacts, ini^ht cora. t jfi 
cone usum that ea..h spene. ha.l not h.^en ind' ,..„!, /" 
T^ah.d, hut had descended, hke va.i,.tio., from othJr 
^peccH Nevertheless, such a conclusion, even if lu 
•.'Hided,.ould he UM..atiHfactorv, until it cJuld 1^ shoin 
hou'the mnumorablo npecies in'hal.uin,MhiH Jorld We 

H ructiire, for u-stance, of the woo.ipecker, «ith its feet 
ta.I, hoak,and ton,n,e, so adn.irai, v adar te 1 to c , 1' 

trees, whch has seeds that must he transnorted hv 
certauj nrds, and whi.-h has /!o«-ers with se S e^^^^ 
ahsolutely re<|u.rin.. the agency of cer Jn [l^cN to 
tTH.i. pollen from one flower to the other 't email? 
l.reposterous to account for the structure of thinaS 
Ih et'^of :"? '' several distinct organic Kn^t^' 

Hie author of the I't-^tiye^ of Creation nould I 


£.;«"';'"' ""'"? I? '"^ ^« '- "« explanation o^ 
eaves the case o the coadaptations of or-ani. hein. s 
to each other and to their physical conditio of e 
intouched and unexplained ' "«'"'^''-- ot lite, 

cleiV'i' ^'.'T^'"''«' "^, t''e hi^rhest im,,ortan.e to train a 

t^.!z^'' .'['^? ^'- — of midihcarion ;.::;;'",:: 

""' ''■'■■ ■■' ' '''0 Collin 

It seemed to xw 
ticuted n 

f I»roha!.le that 

tement of my ohserv.-.ti 

nmials an 

:i careful studvof d 


il of cultivated plants would offe 




best chaiue ot ir.akir.ff out this o1w( urfi prohlem. Nor 
have 1 been dirvippoiiiUHl ; in this and in all other 
ncrplexint? cases I have iuvariahly fcund that our 
aowle.lsfe, imperfect ihoutfh it be, of variation under 
tlonipsti.-ati<.n, atforded the best and safest due. I may 
venture to expre-s mv conviction of the hit'h value of 
such studies, altlioutrh they have been very commonly 
neglected bv naturalists. , ^ » 

From the^e considerations, I shall devote the hrst 
chapter of tliis Al»stract to Variation under Domestica- 
tion. ^^■e shall thus see that a lartre amount of 
heredit-irv moditication is at least po>Mlde ; and, what 
IS e(iuallv or more imjiorUnt, we shuU see how y-reat la 
111.' power of man in accumulatinir l>y his Selection 
successive slight variations. 1 will then on to the 
variability of species in a state of nature ; i>ut I shall, 
unf<.rt.inatelv, \>e comi>eiled to treat this subject far too 
hrietly, as it can be treated properly only by ^iviii^ 
Ion- cat;iloirue.s of lacUs. Wo shall, however, be en- 
abled to discuss what circumstances are most favourable 
to variation. In Uie next chapter the Strutf^le for 
Kvisten.e amontrst all or^nic Injin^ throutrhout tlie 
world, which inevitably foUows fn.m the hitfh a^eo- 
rnetrical ratio of their increase, will be treated ot. 
rhis is the doctrine of Maltbiis, applied to the whole 
animal and vciretahle kinirdoms. As many more 
individual^ f each species are horn than c^n possibly 
survive; and as, conse.juently, there is a trequenUy 
recurring struntfle for existence, it follows that any 
beintr, if it varv however sliy-litly in any manner proht- 
•itde to itself, under the c«)inpiex and sometime.^ varying 
conditions of life, will have a better chance of surviving, 
and thus he uaturaily mected. From the fro"^ 
principle of inheriUnce, any selected variety will tend 
to propatrate its new and modified form. 

•rhis fundamental subject of Natural Selection wiU 
be treated at some length in the fourth chapter ; and 

we shaii Lheii see now >ai! .-eie- <.:'•" ^-^ - ■-» 

evitablv causes much Extinction of the less improved 
forms of life, and leads to wliat I have called Divergence 


of (l.aracter. In the next chapter 1 shall discuw, the 
cornpU. and Ilt.lo k,wn laJs of vanatio,ra"l of 
orrelat.nnoftrnnvth. In the four H^MMM-iirie chapt^,^ 
the most apparent ar.d cravest diHicilties on the tlieonJ 
w.U he^ne.i : nan.oly, first, the diffi<uitie.s of trans? 
tjons or in undersLandinir how a simple hein- or a 

h.*fhl> devoloned bein^ or olahorately construrted 
orpan ; .ec,nul^y, the suhjert of ln>tin.-t,or U e mentol 
powers of animal,; thinily, HyhridiH'n,, o tbe^ 
fertility of species and the fertility of varieties wh^n 
mterorossed ; and fourthly, thfe imperfe<>tfon of the 
.e*do*r.caI Record. In the next chapter 1 « hall consider 
tho<reolo4.ncal succession of orfranic liein^rs thruuphout 
.mo; ,„ the eleventh and cwelfth, their%e< JaS 
d.stnbut,on throui^hout npace ; in the thir'eerfth th^ 
.lassifica lonor mutual affinities, botii when mature and 
in an emhryonic condition. In the L-ust chapter I 61^11 
.nve a bnef reca{,,tulation of the whole work , and a ^w 
coiioludiniT remarks. 

No one outfht to feel suqjrise at much remaininir a. 
yet unexplained m re^rard to the oritrin of specie*, an^ 
vanet.e.s, if he make« due allowance^^orou /profound 
urnorance m re.^ard to the mutual relations of^rtSe 

::,; :f,^';r '^:^-^ --'^-b- and is very numerous, and 
»,^ an,. u_ral!,ed species ha., a narrow ran^e and i« 
f r n 1 f' '•l^latmns are of the highest in.porUnce, 

t>.lKne, the future and modiHcation of everr 
H.halMUnt of thi. «orld. .Still less do we know of the 
mutual relatione of the innumerable inhalutantT of the 
-on. duni,<r the many ce.dopcal epochs in it^ 
^''.^tury. Althou-h much ren.ains obscure, and wiU 
\ou,r remain obscure, I can entertain no dou lafte 
I" rnos delil,erate study and dispas.sionata jud^onenl 
"f ^hu'h I am capable, tliat the vi... ^.yLu^^ l 

^-'l^wTr^^^l:^'"^ "^'''^ ' ^^'■'"^'•Jj' ^"t.rtj;;6d 

.reat^l /. ^'"""^ '^^""T ^'^^ ^^^'^ indej.endentlr 

<rtated-i8 erroneous. 1 am fully conviiced that 


species are not immutable ; hut t)iat those heloii^ing to 
what are called tlie same genera are liiiejil descendanta 
of some (ilher and jfenerally extinct speries, in the same 
manner a> the acknowledfred varietie- of any one specie* 
are the descendants of that species. Furthei more, 1 
am coiivinoed that Natural Selection li.'k; hecn the mail) 
hut not exduHive means of modific<ition. 



t . Mans power of MX-ti!!^,''''''^"'*''''*'' '"vourmhl, 

\ri,KN we l(K,k to the iii.lividuals of the same VHrietv 
or sub-variety of our older cultivated nknts TnX 
amma s, one of the rtrst point, whidi strike us i 
'e inriJ'T'^j^' ''''' ">' ^« ^-^ -'^h other tl^n io 

nature Wh'i "'^ ""VP*^^'^'^ "'' ^'^'-'^^y "> « «tate 
.1 nature. \\ hen we reflect on the vast diversitv of 

the plants and animals which have been c'h v^ed 

iffer;n"cIi*;n':tV""S'/"""*^ ^" ^^^ under the mo^ 
J.tterent climates and treatment, ] think we are driven 

t" conclude that this preat variability is simp™ due to 

d-MonToPlif^n'ot'"''""; '""''"'^ ^«^" --'^ ->'«"o" 
tZ Sil\ T- "J"^?'^ ^' *"'^ somewhat ditferent 
"om, those to which the parent- species have W, 

'" ^^-";-wiis or iijt! lo cause anv aonreriafil* 

Hn.ount of variation ; and that when the orSSion once begun to vary, it generally conUouS^ toJi; 



■ i'A^M''^6: 



for many ^(Mieralionrt. No cnne i* on rt'cnnl of a van- 
al.le bei'ntr ceasii.t; to be varml.le mi^lor .Miltivation. 
Our oldo,st cultivated plants, such as wheat, sUll often 
yii'ld new varieties: our oldest dnme-^licated .imruaU 
are still ca^Kihle of improvement or mo.lih.ation. 
it has been dispuU'd at what peri..- •;: lite the oauso. 
.,1 vanal.ilitv, whatever thev may be, generally aet ; 
whether durintr the carlv or late period of development 
of the embryo, or at the instant of conception, (ieotfroj 
St 11 ilaire'-'experimenU show that unnatural treatment 
of the embryo causes monstrosities; and monstrosities 
cannot 1« separated by any clear line of distinction 
from mere variations, liut I am strongly inclined to 
■usj)ect that the most frequent cause of variability may 
be attributed to the male and female reproductive 
elements haviiiif been affected prior to the act of con- 
ception. Several reajsons make me believe in this ; but 
the chief one is tlie remarkable effect which confine- 
ment or cultivati..n has on the function of the repro- 
ductive system ; this system appearinjr to be far more 
susceptible than any other part of tlie ortranisatiou, 
to the action of any ciiatisre in the conditions of lite. 
Nothint: is more easy than to tame an animai, and few 
thmtrs more ditiicult than to jret it to breed freely under 
conrtnement, <:ven in the many cases when the male and 
female unite. How many animals there are which will 
not breed, thonuh livinir loiifr under not very clo>e .-(.n- 
tiuement in their native country! llus is ecneraliy 
attributed to vitiated instincts ; but how many cultivated 
plants display the utmost vitjoisr, and yet rarely or never 
seed ! In s.nne few such cases it has been discovered 
that very trilling chan^'es, such as a little more or less 
water at some particular j.eriod of trrowth, will .letermiiie 
whether or not the plant sets a seed. I cannot here 
enter on the copious det.iils which 1 have collected on 
tliis curious subject ; but U> show how sintrular the laws 
are which determine the reproduction of animals under 

coiihneineiu, i may ju^-t nivniiuii tn^i. .a,,,.--> » 

animals, even from the tropics, b-eed in this country 
pretty freely under continement, with the exception of 


the plantitrrades or bear family; w l„>rea.s can.ivo.o.,, 
t'inis with the rarest exceptions, hanllvever lav f.-rtile 
eniTH. Many exotic i,hiubi have pollen utterly H(;rthU.«s 

m the same exact coiMitioiia.s in the most sterile hvhridx' 

\\ hen, on the one han.l, wo .ee dr.mestiratf.l animals 

ajul plaiit^, th<Mu:h otlen weak and >icklv, yet hreedinir 

Viite treely un.ier continement ; and wht-'n, on the other 

hand, we see individuals, thoiith taken vountr from a 

/ f r ''•''!'"-«'Jf f'-^-'Jy tamed, lon>f-lived. an.i healthy 

(Of which I could ^ive numerous iiiKtmces), v,.t havinir 

their reproductive system so serioualv affected hv un- 

perceived causes as to fail in actintf,' we need not }>e 

HurpriHed at this system, when it does act under con- 

hnemeut,actuiff not quite retfularly, and producnijf otf- 

spring not nerfectly like their parents. 

Merihty has been said to Iks the bane of horticulture • 
l>ut on this view we owe variability to the same cause 
which produces sterility; and variability is the source 
ot all the choicest productions of the garden. 1 may 
•ifl'l, that as some ory-anisms will breed freely under 
tbc most unnatural conditions (for instance, the rabbit 
and ferret kept in hutches), showintr that their repro- 
'luctive system has not been thus affected ; so will some 
animals and plants withstand domesti.-ati..n or cultjva- 
Uon, am. vary very sli^htly-perii.ips hardly ,nore '' 
m a >tale of nature. 

A ionjr list could easily be civen <.f ' sportin^r plantj^ ' • 
'.V this term frardeners mean a sintrh- bud > r offset* 
wtnch su.l.lenly assumes a new and sometimes ver^ 
Afferent character from that of the rest of the plant 
-uch buds nan be propairated by i^raflinir, etc., and 
sometimes by seed. Tbe^e 'sports' are evtremeU 
rare under nature, but far from rare under cultivation ■ 
and in this case we see that the treatment of the parent 
fias affected a bud or offset, and not tlie ovules or pollen, 
't '8 t';e "pi'ium of most physiol<»iri,t« that there is no 
essential difference between a bud and an ovule in their 

-Ui^-Ca O 

support my view, that variabilit 

i loriualion ; so that, in fact, ' sj.orta 

buted to the ovul 

y may !)e lartfely attri- 

es or pollefi, or to both, havinjf [ 




;3>W-;«S*«^^;^ "MSmX^Q^Si^^ 



affected )iv the treatment of the parent [nior to the act 
of (•t)nce|iti(»ri. These iTise>^ anyli'tw show that variation 
is not iieifysarily conneeted, as some authors have 9U|>- 
|t(»s(Ml, with l)ie act ot ^'cnerat ion. 

Sceillintrs from tlio same fruit, and tlio youn^ of the 
Kirne litter, sometime^ differ ronsideraldy from eat-h 
«)thfr, thoiiirli hoth the yoniiir and the parents, as MuUcr 
lia-^ rt'inarktMl, liave apiiareiitiy ht-en ev posed to exaetly 
the sjiine ronditions of life ; and tlii« shows l„)w iiiiim- the direct effect- of the coniliti(»ns of life are 
•ill cuiipanson witli the laws of reproduction, of irrowth, 
and of inheritance ; for had tlie action of the conditions 
hecn direct, if any of the youiiL'^ ha<l varied, all would 
proliahlv have varied in tliesaine inaimer. To jiidire how 
mu. h, in tlic case of any variation, we siiouhl attiili;:te 
to the direct action of heat, moisture, li^^lit, food. etc. , 
is most ditlicult : my impres-ion is, tliat with animals 
such agencies have jiroduced very little direct eth'ct. 
thmi^'h apparently mine in the ivise t)f plants. I nder 
this point of view', -Mr. liuckman's recent experiment- 
on plants are extremely valuable, ^\■lu•n all or nearly 
all the individuals exposed to certain conditions are 
affecteil in the same way, the chaiiire at first appears to 
he directlv due to sucli condition? ; Imt in some it 
can l>e sliown that quite opposite conditions produce 
similar chaiifres of structure. Nevertheless some slijfht 
amount of dian -' may, I think, l)e altrihuted to the 
direct action of the conditions of life— as, in some cases, 
increased size from amount of food, colour from par- 
ticular kinds of food or from litfht, and perhaps the 
thickness of fur from climate. 

Hahit also has a decided influence, as in the period 
of lloweriiii^ with plants when transported from one 
climate to another. In animals it has a more marked 
effect ; for instance, I find in the <lomestic duck that the 
hones of llie win? wei;rh and the hones of the let; 
more, in jtroportion to the whole skeleton, than do the 

)u;;cs Hi i;ic: •.-. uti •..!:"> n. , n-.-.-^ i j-i' -•■ '••■• 

change mav he safely attrihuted to the domestic duck 
flyiuff mucli less, and walking mure, thau it« wild parent. 




TTie^roat and .nherited devolopment of th,. ,.,{ l.-rs in, ,„ co,„,,aris.„. with ti.e s,at,. of tin' e ™^ 

"Ml. .Not a sMiL^Ie d.)mr>f;r animal can bo named 
^In.h not in Home rountrv droopin . .L Zd 

:!"•• to tlu. .i,M,so of the m...,I..s r,f th.. ... ir from the 
animals not he n-' much il .n,,...! i j 

n ,.n ; "*''.''" y^''*-".-""! «H1 he hereafter hriefly 

n.entuned I w,l) here only allude to v,hat n.av e 
•■■'lledeorreK.t,onoft,ro«-th. Any -han^^e in , e e t o 
'.r larva «,11 almost eertainlv 'entail eha,,!'. ,2 

jnah,rea, Inmons,ro.ties.theeorr;iiio : 
"eon .ju.te .l,stnu-t parts are verv eurious : an.l mar.v 

n.stnneesarotf.veninlsi.loreinM.rfrovM. IliVnr '.T^^^ 
'vork on th.H suhje.-t. Mreeders helieve tl . .; hi: 
are ahnost always accompanied by an eIon.^.t;d lu' 
crV'lf '■',";"" of correlation are .[uite whin^iea : tbt 
cat^ «,th blue eyes are iuvariahlv deaf; colour and 
oust, ufonal pecul.anties ,.o to.^eiher, of w lie rna 
emarkab e eases could 1^ ,Mven amon^^st a, m Is a . 
plants Prom the facts collected hy lleusin-r.-p /"' 
prs that whke sheep and pi^.. are ditrerentU atfecUd 
n)m coloured ndi^idual8 by cert;iin ve.^et. 1^ ,t so h 
Hairless do^, have imperfect teeth ;,;- ai ^ Zd anin.aLs are a,.t to have, a. is asscr ed lout 
or many horns; pi.^eor.s w'.th feath;red f'et W^ S 
between he.r outer t<,.s ; pi,.c.,ns »ith short h^i'ks ha e 
mall feet, and those with lon^ beaks lar.^e feet I e nee 

" hrr%r "■l;"'";^' ^"' ^^"« -^mentln^an; 

Afii ® '^'"'^ ^^'"""^^ certainly unco'i^cn.n.i;- 

' 'dify other parts of the structure, owi,?^ t^ u^^ 

-..-tenous laws of the correlation of ^'owth.*^ 

J ''«/esult of the various, quite unknow,. or .V,^l.. 

^Tersilu^r t -'"""n'" '^ '"''"it^-ly complex'aud 
in.rsn,ed it is well worth while carefuUv to studv 
ti^e several treatises publishe<l ou some i'f If "Id 



«-iiltivatt«<l {>I:iiit.-. .1- on tli*' hyacinth, jioUito, pvfti th« 
(lahl'.i, ••;' . iiwl it 1- r»'j»lly Hurprisiiiir to note th»* 
rndU'^^N (("lilts in stractiin> :uul coiistitiitifiti in which 
th«i vari«'tit'h and Hiilnvarit'tioH ditfor «lii:htly frnrn e.'i»'li 
other. I'Ik' whole or;:.iniMalion seems to h.ive herome 
jihistic, imd tends to (lepart in some «mall dej^'ree froi.i 
that of the |>irental type. 

Anv v!ir ition wliuh is not inherited is iinimportiint 
for us. I'»ut tlie nuinh«T and diversity of inheritaMo 
deviations of stnictii re. iiolii those of slijrht and ttione ot 
cnnsideralile phvsicdotfifAl imporUnee, is endless. I>r. 
Prosper i.ucas s treatise, in two hirjfe volumes, is the 
iiillestand ttie ».est on this suhjoct. No hreederdouhta 
liow str«»nir is the tendency to inheritAiice : like produces 
like is his hjiidamental helief : douhts have heen thrown 
on tliis principle hy t»'eoretical writers alone, \\hen 
any deviation of structure often appears, and we see it 
in the father and child, wo cainiot tell whether it may 
not lie due to the same cause having acted on both ; 
hut wlien amonjist individuals, apparently exposed to 
the same co-idilions, any very rare deviation, due to 
<n'iw extraordinary co'mhination of circumstances, 
appears in thejtarent —say. once amonjrst several million 
individuals -and it reap'pe^ira in the child, tlie mere 
doctrine of chan."s almost compels us to attrihute its 
reappearance to inheritance. Kvery one must have 
heard of causes .>t alliinism, prickiy skin, hairy hodies, 
etc., appearini: in several memhers of the sjime family. 
If s'trantro ana rare deviations of structure are truly 
iiiliorited. less stran^re ■itid commoner devi.'.tinns may 
he freely admitted to he inheriUihle. I'erhajis the 
correct wav of viewiiij; the whole suhject, would he, to 
Inok at the iiiheritance of every character whatever as 
the rule, and non-inheritance as the anomaly. 

I'he laws ijoverninu' inherit;iiu*e are <|uite unknown ; 
no one can say whv a peculiarity in different individuals 
of the same' species, or in individuals of ditlerent 
at-.«."p2 js ^uTr-.oti'ne.s inherited aiid. sometimes not so ; 
v*'hy the child often reverts in certain characters tr 
its grandfather or ^rrandmuther or other more remote 

Mt :i/^^.^^^^«i^ 


"u-^rt;,"!;?;/' ''""'"7^^ '" "^"" t— "tted from 

"li- M. th«. ruHlrs of uur br,'..,|H ,-»r,. ofVn trl 
ra.Ued e,ther i„ a „mh-1, .rirt.Xr " : 
•ii.''* alone. A mn.h more imporUnt rule hJ .h r 
t»' Mk may Ue trnHtc,,!, m that, at ihatewr , eriod i,' 
;' l-ouhanty aH...arH. it t.,..!. to ap,...,.r u/tre 1 .r ,^' 
. . co,,,,j„. ,„.^, U.ou,.h sn'oletimos oar ,V n 

'».er,t.,i oerol.anti.., i„ the horr.s of ratt e n. ,1 
M'l-ar only ,n th. orf.pri... v,f,..„ „.,,Hv ^ 
.'-"l'HntM,s Hj the silk.orm are known a, '^ 
'"«' '••.•rrespon.ln.sf cater,„|lar or cocoon ^t^i- .' M 
'.CMe,|.tary ,i,,.s an.l' .o,„e other :.t:,"ke n . 
i'«;li«ve tfiat the rule ha. a wi.ler evu-r '.h. ," I t^^ 
v'I.erj there is no apparent reason .;'''' :..;;.';''; 
>lmuhl appear at any particular a^^e A-t tint I ■ 
t"".'l to appear in the iffsprin^ at th; l. mj 1 , , I'r 

u the crossed orfspnnir from a short-horned cow hv ^ 

I ad II. .'.'*''":"'''•-' ^■"'■i^ties, „hen run wild 
!.rad ally hut certainly revert in character to the ; 
.|l'or..nnal stocks. Hence it has heen ar.ned that 1 

';^.^:^'!.:^r "?• . ' »-- - -- endeavou/ed S 

Ijaij .' 

icisive j.n in liie 

■^o of^en and so holdly heen ma«ie. 'II 

?T&it dithculty in proving its truth 

a|)ove statement 
lere would l>e 

we may Kafely 



ronclude that very many of the most stroiitrly-marked 
Jtiinestic varietiert could not po^siMy live in a wild 
■;tate. In many cases wo do not know what the 
ihori^inal stock vvas, and so could not tell whether or 
not iic.irlv perfect reversion had ensued. It would he 
(juite neces>ary, in order to prevent the ettects of inter- 
cnissini;, thai' only a sini^lo variety should he turned 
loose in its new home. Nevertheless, as our varieties 
certainly do occasionally revert in some of their 
(haracti'rs to ancestral forms, it seems to me not 
niii>n»h;il)li>, that if we could succee<l in natural i.-iiiir, or 
were to cultivate, durintr many ;renerations, the several 
races, for instance, of the cabha^je, in very poor soil (in 
which case, luiwever, some etlect would have to !»e 
attrit)ute<l to the direct action of the nooi soil), that 
they would to a lartre extent, or even wholly, revert U) 
the wild aht»ritcinal stock. Whether or not the experi- 
nunt would surceed, is not of f^'reat iniport-ance for our 
line of ar-^ument ; for hy the experiment itself the 
condition- of life are chani,^ed. If it could he shown 
that our thmiestic varieties manifested a stronjjr tendency 
to reversion,— that h, to lose their acipiired char- 
acters, whilst kept under the same conditions, and whilst 
kept in a considerable body, so that free intercrossing; 
mijrht check, by Mending 'tofjetlier, any sliii^ht devia- 
tions in their structure, in such case, I jrrant that we 
coul'' deduce nothing' from domestic varieties in regard 
to si)ecies. Hut there is not a shadow of evidence in 
favour of this view : to assert that we could not breed 
our cart and race horses, long and short horned cattle, 
and poultry of \arious breeds, and esculent vegetables, 
for an alniost infinite number of generations, would 
he opposed to all experience. I may add, that when 
under nature the conilitions of life do change, varia- 
Li'J-;s and rever>i(in> uf character picbably do occur ; 
but natural selection, as will hereafter be explained, 
will determine how far the new characters thus arising 
sha'l !>e i.Tc^^'T^ od, 

W'hen'.ve look to the here<iiUiry varieties or races of 
our dome^tic animals and plants, and comjKire them 







-ith closely-allied spccie-s, we Renerallv porreive ,n 
"(ich domestic race, as already rennrU/ll 
'orm.ty of character than i„ tn.o m^ es ^' tm.e ti" 
-.•es ot the san,e species, also, otle,! lu ^e a I^ZXa 
monstrous character ; hy which I mean, that u In : 
. hjern... from each other, and from otle ^l ' t ^ 
t ij trenus, n. several trilling, respects, tl ev , te 
a^rfor ni an extreme de^rree in^on.e one ar ot 
-hen compared one with another, and more'espec 
nlH,„ compared « all the .pecies in nature twf. 

wth hat ot the oerfect fertility of varieties w „ 
. n.ssed a suh,,e.-t l.ereafter to he discussed), d,,, es j c 
r_Ke> ot tue .same species ditfe.- from each ot e t ^e 

jame a.s, only in „,ost c.ise« in a lesse de..ree 
than, do closely-alhed .pecies of the .vime -enus m ^ 
st.ite of nature. I think this mu..t he adnnUe w en 
Tm. ;;:;^t f ''''? "^ ^^^Y^^-^ any do„H.stic"a ''e^t t 

»t,itU that domestic ra,cs do uot differ from ea, 
otlier „■ cliaracterB of ffonerie value. I think" eou] 
l« sliov,,, that this statement i, hardlv 'ima S 

turnl T^*" ''"*'"V" ^-^ estimate the amount of struc 
tiiral difference hetween the .lomestic ri es of 

-uid he sh„»„ that u,e ^e>-h;„;i;d!"h;";di,ruj,' 


terrier, spaniel, and buU-dmr, which we all know pr<v 
Se tbeir kind bo truly, were t 'e offspnns of a^ry 
Sle species, then such facta would have trreat we.^^ht 
i mak ng us doubt about the immutability of the 
n a,^ very closelv-allied .mtural instance 
o e foxes-inhabiting different quarters ot he 
«or Id I do not believe, as we shall presentlv see, tha 
he wbole amount of difference between the sever^ 
hreeds of the doi? has been produced under domestica- 
ti ml believe that some small part of the d.tference i8 
due to theii bein^r descended from ^^f "^^V^^P^^''^,;- /" 
the case of some other domesticated «P««^|f '/''?/« ^ 
..resumptive, or even stron,, evidence, that all the 
bretds have descei .'d from a sinj^le wil • stock. 

11 ha.<.rten been assumed that man aas chosen for 
aomesticati..n animal, and plants having an extra. 
or Imarv inherent tendency to vary, and likewise to 
wi nd diverse climates. I do not dispute that these 

ran- cities liave added lar-ely to the value of most of 
riiomesticated productions ; but how could a sava.e 
possibly know, when he first tamed an animal whe e 
it would vary in succeeding generations and Nhetber 
would e.ulure other climates .; Has the little vana- 
ility of the ass or guinea-f.,wl, or the small pjm^r 
/endurance of warmth l>y the reindeer or of cold by 
the common camel, prevented their domestication 
cannot doubt that if other animals and plants, equa^ 
n u ber to our domesticated productions, and 
elongng to e.,ually diverse classes and countries 
ere fiken from a state of nature, and could be made 
o hreed or an equal number of generations under 
l" mestication, they would vary on an avera^a- as largely 
tTlu- parent spec'les of our existing domesticated pro- 

'"^n 'X'^r'^^tost of our ancienUy domesticated 
anna and plants, I do not think it is possible to 
^"'" :./..„. H«h,ut« conclusion, whether they have 
i^si^nde.! 7r..m one or several wild snecies. The 
a ^imeiit mainly relied on by those -»'« - '«^« " *^« 
multiple oritfiu of our domestic animals .8, that we 


finri in tliP Hunout records, espo, aJlv on 

and t at some oMl.e breeds closely resemlde, pc' ha ,J 
.-e ideMtical v,,tl,, those still exi'.tini,. Kv .„ if th ' 
-.ner fa.t uere tuuMd more «trictlv and ^^ener, I true 
't..-^n see,,,,, to n.e to he the ease, what diH-^ itlhow 
nut that Kon.e of ..ur on.n'.KHled t leTe, fo, r «; 
^ ve thousand years a,.> : |i„t Mr. Horner's re'se^n^.^ 
1'" •-• re.Hiered ,t m some decree prohahle thaf n a^ 
^.Whnently nvili.e,] to have manufaetu ed n .trerr 
ex.sted m the valley of the Nile thirteer/or A urteoJ 
-.u.a„d years a,.o; and v ho will pretend to Ty £ 

rra d..] j. ,„.^.„ „, ,Vusti dia, who possess a 8emi- 
<i'> ' t'.tic doir, may not l.r, existed in Wvpt > 

Jhe whole suhiect must, 1 think, remain va^ue ■ 
nevertheless, may, without here ^n.^rin^" o,?^!"' 
dt, state that, from peo^raphieal and r^her rtm 
M.ieratH.ns J think it hi,.hh* prohahle t at or have descended from seve U wild Known,.., as we do, that sava-^'s are ve > 
fond o tanun.. ammals, it seen.s to me unlike in Je 
s .?//" '-'--^^onus, which i« distrihuted i/awild 
Ktate throu.^hout the „„rld, that since man firs 

' > "le I,) Mr. IJlyth, on the hah ts, voice and rn„ 

I'-lieve tl.arthese l.tter lir ? '"""'Patent jud^., 
J'.^rent \\ it , ro ^ f . 1 had more than one wild 
I .rcni. n ,n, re,,i.ect to liorses, from reasons which I 
cannot true here, i am douhtfu Iv inclimn lo S 'v. 
in <>PI...Mt!on to several authors nil I ''*'^'^*^*-' 

^--ended tn,n> one wild stock 1,'r h-tT'^w^" 
:'l:-::-; '-», his h.^ and varied .to^s of illl^.^r 

■ •■..*A\i *itiijt* iiifift* iiiin #1...* ,1-1 . . ^ ' 

iniost anv one. thinks 

•'"t all tht hreedsofpoultr'vL... 

»-ommon wild Indian fowl (('alius hank 

lave proceeded from t} 


iva). in 



•.;r^:.-^ r' 




U) (lucks and raldiits, the breeds of which ditfer con- 
Jii(ltT;il)ly from oacli oilier in strm^ture, I do lift doul>t 
that they lirive ail descended from the common wild 
liuck and raltliit. 

The do<-trine of tiie oritjin of our several domestic 
races from several ahori;;iual wtocks, has hoen carr'ed 
tu an ahsurd extreme \>\ ^omo authors, 'lliey l)elieve 
that every race which itrceds true, let the distinctive 
characters he ever so >iit:ht. lias had its wihl prototype. 
At this rate there must have e.visted at least a score of 
speciea of wild cattle, as many sheep, and several eoars 
ii! Kurope alone, and several even within (ireat liritain. 
One author believes that there formerly existed in 
( ireat Mritain eleven wild species of sheep peculiar to it. 
\\l;en we hear in mind that I'.ritain has now hardly one 
peculiar mammal, and l-rance hut few distinct from 
tiiose of <ierinany and conversely, and so with Huiijrary, 
Spain, etc. . hut that each of these kingdoms possesses 
sfveral j)eculiar breeds of cjittle, sheeji, etc., we must 
iulmit that many domestic breeds have originated in 
Kurope ; for whence could tliey have been derived, as several countries do not jiossess a number of 
peculiar species as distinct parent-stocks? iSo it is in 
India. Even in the of ti;e domestic doirs of the 
whole world, which 1 fully admit have pro! -ably de- 
scended from several wild species, I cannot doubt that 
there has been an immense amount of inherited varia- 
tion. Who can believe that animals closely resembliua; 
tlie Italian ti^reylHiund, the bloodhound, the hull-dog, 
or Hlenlieim s]iaiiiel, etc. — so unlike all wild Canidae 
—ever e.xisted freely iu a state of nature.'' It has often 
been loosely said tliat all our races of do<rs have been 
produced by the crossing of a few aboriginal species; 
hut by crossing we can only get forms in some degree 
intermediate between their parents ; and if we account 
for our several domestic races by this process, we must 
i;<lmit the former existence of the most extreme forma, 

aa -.uc :-,itj;.-;: g i t?_r is- •••••■' -, ' : - -• ,' 

in the wild state. Moreover, tlie possibility of making 
distinct races by crossing baa been greatly exaggerated. 


I'htTC r,in hp Tin dn.jl.t tint- ^ r.- , x 

'1-s. individual nun^r;; ^,i.h';"'''''' -"'-*-" "^ 

^F--.e. '.ant:d;vrii:r"^ri'^Tr7-"^"'^ 

- '.-I^-rahlv and ^J^^J'^^TV"''' P"re hro-ds 

^inple enough; hut whonfT". "^•^''•vth.r.s,. ,eem., 

•no with a,.:.t! or or ever!l " "'"'l^'-^"'^ ^^« ^Tossed 

'-rath.. ..,;';;:;- t^"^e^^.on.ed.H<..,,^,, 

'•^ en; ,r.Hnrt } reeds on d ^nTT'^""''^ '"^*"'*'*^" 

'•"'I •-> sind e on «: .r ' •''"'^ "''"'*"" • ""'• <•«" ' 

!'een th„:f„rmed ^ ^ P«rn,anent race havintj 

have, aft.r del 1 orat .n r.k- "' "^"'f ^f'*"'*'^^ ^'"""P' ' 
' ''-•" '-F't e or Cd whiU'^r ''"T'^^''" f*''^'^"- 

^V-m several <, e^ o/ TL I ' •'. ""'""'^ "'*'' ^"^'"^ 
tf)" FIo„. U- *FM orfrL - ^•"■'''' "'"'•e especial I V hy 
>'-ray r>on, iw >"^,C ^^' -f »>>' the Hon.(^ 

l-'n.uaees have heen .uld shed T " '" ''''^^'■'^"* 
o' thorn are very im,. r f "■ P'^'*'''"^ «"d .on,.- 

«''ti■|.-:U^ r ^^veT. 'T ^""-^ "^' ^""^i<lorah!e 

^•'^"^■-rs and have h'^''* ^ ^'*^' "^''^'^^ «'"i"'*"t 

-'nnnhi,,. a.t. n s In^' r '^"'*"'"'i^>' "'^ ^^'^ ^^'-^'"'^ '"^ 
-Hi the ;},or ft ;^^^^^^^^^ f-^-'^'lish .arrier 

Hiri-on.,u-e. i, their kuHn '"'•"- '•'>'-'-«^^Po,ulin.. 
L. .Ionn,ll. '.I-'.;''.""' remark-aide from the wonderf,.! 

"" this-;. .;;,-;:;,:::^'t;;:'i;^::^.fi<^i-^ .,.ad; 


to the nostrils, avA a »nd« 





^'•p^ of inoiitli. Tlic phort-farod tuinhltT lias a iicak 
III oiilliiie iilnutsi like of a tiiich ; aii<l llio ("Oimmni 
liirn'liliT has tliP irilierited li.'ihit of liyiuf.'- at a 
j^r«'at heitilit in a coiiij)act llock, and tiiinhliiitr in tUo 
air lipaii over heels. The runt in a iiinl ot t real size, 
with luntx, massive heak and lar^^e irel ; Borne of tiic- 
8ul> liree<ls of runts have very lonjr necks, otiiers very 
lon^ wintrs and t'uis, dIIhts sinuularly short ta'ls. 
The harh i- allied to t! • carrier, liu»., in.-tcad of a very 
lon^' heak, has a verv !=hort and very hroad one. Hie 
pout«!r has a much elon;:ated ))ody, wiiiL's, and lep* ; 
and its enormoubly (levelo]»ed croji, which it tfioriet- 
in infhiiinj;, may well excite a.-tonishinent an<l even 
lauirhter, 'lite tiirltit has a very short and conical heak, 
with a line ol reversed feather.- dowTi the lireast ; and 
it has the hahit of continually exiiandinir slitrlit!) the 
ujijter i>art of tlie trsophaeus. 'I'he .>at oldii has the 
feathers so much reversed alonj: llie liat-k of the neck 
that they form a liood, and it liaii. f)rM|Kirtioriatly to it>> 
size, much elon^-ated wiiifr and tail feathers. 'Hie 
trumpeter an<l lautrher,ap their names express, uttei" a 
very ditierent coo from the other lireeds. The fantail 
has' thirty or even forty Uiil fe'.tliers, instead of twelve 
or fourteen, the normal numher in all memhers of the 
fieat pifreon family ; and these feathers are kept 
expanded, and are carried so erect that in i:oo(\ hirds 
Uie ii"a(land Uiil touch ; the oil-^land is <juile ahorted. 
Several other less distinct hreeils mitrht he specified. 

In the skeletons of the several lueeds, the develo]>- 
meut of the hones of the face in leiiji-thand hreadth and 
curvature differs enormously. I'he shajie. as well as 
the hreadth an.i lentrth of the ramus of ilu- lower jaw, 
varies in a highly remarkahle manner. The numher 
o!' the caudal and fvicral vertehra* vary ; as does tiie 
huinlier ot the rihs, together with their relative hreadth 
ami the presence of jirocesses. Tiie size and shape of 
the ajtertures iu the ^ternum are hitrhly varialde ; so i.« 
/I i y/\»-.?-.»»»f^;» ?\!id rel-^t'.ve s.i/e of tliO two 

arms of the furcula. I he proportional width of the 
^-f^pe of mouth, the proportional len^^th of the eyelidH, 


■>t the (.ritire t.ftlif nostrils or'tlio K.ti::iie (not aiwavs 
in >trict corr.'I:iti.ui with the li'ii-th of lieak), tli.) ^ka 
of the crop an. J of tho npj.flr prirt of tht« ..-sophair-n ; 
!jit« ilpvploptn.'iit ;iiul ahortion of the oil-i,'l,in<| ; " the 
nufTihcr r,f tho primary wintf ati.l caudal f.vithers'; the 
r.iativo h'Uizth of wiiiir and fill to each other and to 
t(iol)ody; tho roI.iti%-e length of Iva and of tho feet • 
die nnmher of sciitell* on the toes, the deveh)pfiient 
ot sKui h.-tween the toes, are all points of structure 
whic}, are vinahlo. Tlio period at «inch tlio perfect 
plurnriire is acunred varies, as does the state of the 
down with which tho nestlintr hirds are clothed when 
hatched. 1 ho shape and size of tho ec'^s vary I ho 
marnier of flitrht differs remarkahly ; as does'iii so,„o 
t.r-c s tho voico and disposition. Utitly, in certiiin 
breeds, the niah-s and female, have come to ditfer to a 
lUitrht dcjrree from each other. 

Alto-ether at least a score of nitreons mi^rht he 
cho-en, which if shown to an ornithofotrist. and he were 
told that they were wild hirds, would certainly, I think 
t)e ranked hy him as well-defined ppecies. Nioreover' 
I do not helieve that any ornitholotrist would place Uie 
hnt'lish carrier, tho short-faced tumhier, the runt, the 
harh, p..ut«r, and fantail in the same «;enus ; more 
especially as in each of these hreeds several truly- 
iiiiiented sub-hreeds, or species as he mitrht have called 
tiiem, could he shown him. 

tJreat a.s the differences are between the breeds of 
piireons, I am tully convinced that the common opinion 
ot naturalists is correct, namely, that ail have de- 
s< ended from the rock-pigeon (( olumba livia),includiM/ 
under this term several s:eoirraphical races or sub- 
■^pecies, which ditFer from e^tch other in tho most triMir'ir 
resj,ect,s. As several of the reasons winch have led 
to this belief are in some de<,^ree applicable in other 
c-.-es I will here briefly ghti them. If the severiJ 
I'l-oeds are not varieties, and have not pr-r-oeded from 
■-.:■■■■' rorK-piaeuii. Liiey must hav« descen.led from at 
lea^t seven or ei-ht aboriginal stocks; for it Ls iir^ 
po>riit>le to make the present domestic breeds by rl4# 






cio-.sii,4/ of aii\ ioss('r nuiiilitr: hovv.for iiistarif.-, could 
a fMiiiUT !k- pruduct'd hy iro>,,r;j two Kr.'f.iv uiiU-s> o:ie 
of till- iKf.-Mt-stnckb pus.--e.-,seu thf clirinu-len^tic euor- 
m«.u- LTdj,.- llm supposed al.(>r;-ni,il storks must 
alJ iiavi- U-.Mi rock-pit', i>, uoi iin'»>dii,jr or 
williiii.'iy perilling on trees. tJut besidtw C. livia, with 
lt« ^-»M.:, sub-spe.;ies, only Iwn or three otiior 
speeies ul rork-pit^eoiis are kiiovvij ; and th.-M- have ii..i 
any ot tlie cliara.fers (j( tiie domtstic iireeds. Hen.e 
tlie supp.iMMJ ai.ori.riual blocks muM either still exist in 
the countries where li.ej vvere onuniaJU uoinesticated, 
and jet ho iinkno>\n to ornitholotMsts ; and this, .on- 
>iderinir tluir si/.e, hahit>, and reniarkahle characters, 
soeiiiN very imjirohahle ; or thev must ha\e he.,,n.e 
extinct 111 the wild state. Hut hirds hreedin^r on preci- 
pices, and ^r„„d tliers, are iiulikelvto he uxterniinai.jd; 
and the common rock-[»i«:eun, 'wliich has the same 
hahits With the domestic hreeds, ha., not heen exter- 
minated even on several of tht smaller IJritish islets, 
or Oil the chores of the Aiediterraneau. Hence the 
supposed extermination of so manv species havin>< 
sim.lar hahits with the rock-pitreon seems lu me a vcy 
rash assumjjtion. Moreover, the several above-named 
d«.mesticat.MJ hreeds have been trausporte«i to all parts 
ot the world, and, therefore, some of them must have 
been carrietl hack a^ain into their native country ; but 
not one has ever iiecome wild or feral, thougii tlie 
dovecot-pijreon, which is the rock-pij^eon in a very 
slif,'htly aiucrtti state, has become feral iu several placets'. 
Ayain, all recent experience shows that it is most 
diliicult to ^^et any wild animal to breed rreeiy under 
domestication ; yet on the hypothesis of the multiple 
oriffiu of our pi^^eons, it must he assumed that at hvi^i 
seven or eijrht species were so thon.uehly domestic*»ied 
in ancient times by hali-civili=ed man, as to be ^uite 
proliiic under continement. 

Au arjjument, as it seema to me, of trreat weijjht, and 

=e-'erhl other 

s_>ecitied breeds, thou^-^h a^rn-ein-' ^'eneraliv m cou- 
BtitMtum. habits, voice, cohiur.nji:, and iu mo>t jiarts of 


tl.:f ^rrurtnrP. with the wild rock-pi-oon vet ar« 

. t of ( oluM.lmhe f„r a Leak like that of th». 
..^^I^h .-arn.r, or that of the short-fare.l tmn .ler " r 
Mrh: h„. nMersnl feathers like those of the c.hi, 

■u! he.-„me extu.ct or unknown. So'm- nv str m 1 
^.u.enne.s...nnon,ei,npn.l.ahlein\rh^^^^^^^^ tarts in re.Mnl to the ...Innrinj. of ,„.r,,, ./„h) 
. ;^erve oonsHieranon. Tl.e n,..k-p::,o;;„ i^'-T^Uw 
'"it. an I has a white (the Indian suh-<„eeies r 

';:::;r^.^^::'.::^r'^'-''^'^-i''^'ti.,.,i.h, tii:^ 


— ".;;.i .i.;rk ,„. wmV,,,;' li^^ . ' : /J ' , „ 

.■■< erually e,lt.e,l with while: the «,„., h,,ve t„ , M ." 

InilyiMhl liree.U have, hesid„ the two hH.-!, ] , ,il- 
"...».» .heciuer.,! will, |',|.,„|,. These °e er' I nS. .ta 
.■; o..c„ , ther i„ .,„y „ther «,«ne, ^f Ztlt 

I cros..e(l some uniforinlv white fant-iik w// . ' 

'iinforniK. M 1, i i • , '""- 'aniaijs with some 

•":;;• ™!;,i it.!; »; t..^'i i'z^^':^rL -T' 

pire black h;.rl, was of a^ heaiitifijl a ^.l— ^-i....- ^ ". 

^■^^itix:;?^ f"";!'' '^^•^'^ wuu;-ha;:an,iwn;i;;;d 

Mi^e_flfre«J Uii]-teathers,asanvwild rock.rmrei.n i U« 
-. under^nd the^ fact., on {he vrell-k^Vw^illnnciple 

»;<--■ -i- T,"c3^ 



ON If IK ()KI(;iN OK S|'K( Ih'^ 

of rovers:. .11 to aic-csiial .li.irarter'^, if ill tlio donio^tic 
Itn-fil-. li.i\n (le><»'ii(iiMl fruiti iliu n)(K-ji!irc(iii. I'mt if 
wii (li'iiy this, wi> iiiiisi tii.ikt' tino of tlif two follow injf 
luLrlily iiii[' sii[.|.(.->itions. K:iin'r, firstly, tlint 
all the s«'\it;i1 itiiauiiii-il ahoriiriiiai storks were 
coloiiroil and iii.irkcd i.kc tlit; rofk-|ii::ci>ti. althoiii.'h no 
otluir exNtiiiLT >in'<ic,s is thin coh.urfd iiid marki-d, so in wich -I'parato tin'cd tlifrw initrht !k* a tciidericy 
to revi>rl to the very wiinu colr.iiis and niarkiiiirs. Op, 
secondly, that each l>re«'d, even the pure-^t , has within a 
d»t/eii or, at, within a M-nni of irenerations, '.eea 
crossed hy the rock-[>ii,'eon : i s;iy within a do/eii or 
twenty generations, for w« know of no fact coiinteii- 
.Tiicini,' the helief that tlie child ever reverts to sonio 
one ancf.tor, removed hy a trrealer niirnix^r of genera- 
tions, in a hrt'i'd which lias heen crossed only once 
with some distinct brei-d, tho tendency to reversion to 
any character derived from such cross will naturally 
hecome less and less, a-s in each succeedinjr ereneni- 
tioii there will Ik) less of the foreij:n blood ; but 
wlieii there has U'en no cross with a distinct breed, and 
there is a tendency in both parents to revert to a char- 
acter, whicli has been lost durinj< some former 
tjeiieratinn, this tendency, for all tiiat we can see to 
the coiitrary, may be transmitted undiminislied for au 
iudefmito number of K-enerations. Ihese two distinct 
cases are often confounded in treatises on inheritance. 

Ivistly, the hybrids or nioiifrrels from between all the 
domestic breeds of pij^eons are {>erfectly fertile. I can 
state this from my own observations, purposely made, 
on the most distinct breeds. Now, it is difficult, 
nerhaps impossible, to brintr forward one of the 
hybrid orisj)rinir of two animals clairly <li.stinct beinj? 
themselves jierfectly fertile. Some authors believe 
that l()n>j:-contiuued d* mesticatiou eliminates this 
stroiitr tendein!y to (terility: from the history of the 
doiT I think there is some probability in this hypothesis, 
if applied to species closelv relatt-d toirether/thouirh it 
is unsupi)orteil by a sinirle experiment. Hut to ex- 
teud the hyjtothesis so far as to suppose that speciea, 

■ 'ii'Vi-ral 


vljoniririally as distinct i»8 carriors, tiiml.lors, nouters 
\u>\ f;iiiUilH now are, hI.ouI.I viel.i r.ff.j.rintr p.-rtei tlr 
f.-rtile, iuf>T »r. sot'rns to ri..' ra>l. in tli." Hxtn>nu'. 

Jrom t}u«H« .^everiil rousonH. naiiu«iv. tliB 
-»f man liaviri:r foiiii.-rlv trot Mjven or pijfht Mipposcd 
.[Mvif^ of pi-roriH to i.rr.'d tr.M-lv uii.ier dono'sUca- 
'-ion; these Mi|.p..vf.,l s(>..,■i..^ hfitu; ,,„ite unknown in 
I wild .^tate, and their Ix-.omiinr iio^*li,.re feral ; tliese 
species liavuii/ very af.iiornial charaeferH in certain r»v 
|'pe<-tsasr..nip.ire<l with all other ( olunil.i<in.. tlioii^rl, «„ 
liko in most other re^[.e.t^ to the ro.k-pi-ron ; the blue 
roloiirand various rn.irks ocrjuiionaiiv a,.peann<,' in ail 
Iho hree.i.s, hoth wJien kept pure alid whon crosw'd • 
the monurel otf-^prinj^ \n-,nyr perte.-tlv fertile ; from 
tliexo several rctsons, taken to-ether, I ran feel no 
•louht that all our donie>tir breeds have descended troni 
the ( omniha livia with its jreoi^raphical sub-species. 

In tavour of this view , 1 may add, firstly, that C. 
livia, or the rock i)i;reon, has been found capable of 
domosticatu.n in Kiirope and in India ; and that it 
agrees m habits and in a ^reat number of pointj* of 
structure with all the domestic breeds. Secondly 
aitlinuirh an Kuirlish carrier or short-faced tumbler 
differs immensely in certain characters from the rock- 
pii,'eon, yet by comparing the several sub -breeds of 
these varieties, more especially those broutrht from 
distant countries, we can make an almost perfect series 
b»>iween the extremes of structure. Thirdly, those 
characters which are mainly distinctive of each breed 
fur nistaiice the wattle and len>rth of l)eak of the 
carrier, the shortness of that of the tumbler, and the 
number of fiil-f.athers in the fantail, are in each breed 
eminently variable ; and the explanation of this fact 
will be obvious when we come to treat of selection 
fourthly, piireons have been watched, and tended with 
tbe utiiio,,t care, and loved bv many people. Ther 
have been domesticated for thousands of ve^rs ia 

tjii.iftcnj or toe Woriii 

; too earnest known 

'u^T ''^ l^"-"'«"« '^ '" t^'^' Hfth ^:Rvptiandvna-stv, aboul 
<>«-«X) B.C., aM was pointed out to me 'by I'rofesaor 





I^pHius ; hill Mr. Hircli iiifnrms mv tJiat pipeon8 are 
jfiviMi in a liill of" fare in thf |»ri'viiius (Jvtiasty. In the 
tiriM) ot'thti KoriiaiiM, as w<- ht-ar fmrii I'liiiv, iriimctmp 
pru-eH v»»Tfc tri\«-ii for pif^r^oim ; < nay, they are fcuiii' to 
lliis yan'i, lliat they fan reckon up th»>ir pfditrreo and 
rai-e. I'itrcons wero luuch valiu'd l»y Klian in 
India, ahcdit the year hluo; never le*-' than Jit.iido 
pi:,'('o:is Mere taken ;*it}i the coiirl. ' Jlie tiionarchs 
of Iran and Turan sent liim H«)me very rare hirds'; 
and, continu<>s the courtly historian, ''llis Maje-^ty 
liy crossiiiir the hreeds, which method was ne er 
practiced heforo, h.ix improved tlitim astoniMliinjfly.' 
Ahoiit this wimo |>erio<l the Dutch were as e.i*:er ahout 
piLM'oriH as were tlie old The paramount 
iiiiporLiince of these considerations in exftlainiiii,' the 
immense amount of variation wliich piireons have 
underirone, will he ohvious wlien we treat of S«dectiou. 
^\'e shall then, also, see how it is that the hreeds so 
often liave a somewhat monstrous character. It is 
also a most favourahle circumstance for the productinu 
ot distinct iireods, that male and female pitreons cau 
1k> e.usily mated for life ; and thus different breeds can 
be kept to^^etlier in the sjime aviary. 

1 have discussed the proliahle oriifin of domestic 
jtiireona at some, yet quite insuthcient, lenjfth ; because 
when 1 first kept piy:e(uis and watched the several 
kuids, knowiii;; well how true they hred, I felt fully 
as much dilhculty in believing that they could have 
descended from a cummn-i parent, as any naturalist 
could in comiiiL'' to a similar conclusion in reyard to 
the many spei-it's of finches, or otlier laiffo groups ot 
birds, in nature. One circumstance has struck me 
much ; namely, that all the tireeders of the various 
domestic animals and the cultivators of plants, with 
whom I have ever conversed, or whose tre.itises I have 
read, are firmly convinced that the several breeds to 
which eacli has attended, are descended from so many 
.ihoriLTnally distinct species. Ask, as 1 have asked, a 
ceietirated raiser of Hereford cattle, whether his cattle 
might not have descended from long-horns, and be will 


:M^h you to Moru. I l,av« n.-v.-r ..u-t a Miireu,, - 
;. -u try, or duck, or rul-l.^t, who w.m :,.„ f' |,, 

;" ' tlKit earl, ...ain l,r«tvl wa. .lesr. ...le.l from a 
. > Una .,,c.-.,.s \au Mo.h, iu his trrat..*, .„ n,.ar. 
•i'.'l apples, shows how utterly he .lish-lieves that the sort., tor iMHtaure a Kihston-p.ppin or (o.llin- 
.., |.le couM ever Lave pr.K-ee.le.l from the seeds ot the 
■ .'"e tree. InminKrahie other, .„wl.l w 
-'.ve... J 1.0 exphmat^on. I think, is simple : fron. lon^- 
" '""ue.i .u.iy they are stron;r!vimpn.s.e.l with the 
u.,H hetvveeu the severar raeL ; and though 
t > Hell know that ea.h ra<-e varies sli::htlv, for thev 
; a theirpn/.e, hy,^^ s.,rh slij,ht difteren.eM. >et 

•V Ignore alUenerul ariruments, and refuse to sum 
uj. in the.r nunds slight ciirfereiu-es arcumulated durin- 
... "iy «eneraliouH. May not thnse naturar 
-i- Hho, far le«. of the lawn of 
-fan does the hreeder, and kncwin,. „o mor. than 1,^ 
'"«•' of the interu.odiate links in the Io„tf li,„,s of 

uedeM ended from the «.:ne parents- mav they not 
I'.irn a lesson of caution, when ihev deride the i.lea ./ 
^•.enes ,n a 8Ute of nature bein^ lineal des.-Ciidants ot 
er spetifi: .' 

^ U.J.,e races haye been produced, o.ther fV.-m 

V ni 1 '^-T'^^ ^'''^''' ''"••■'•■^- •'^«""« little erf. ct 
V enf»I ''I'/'* ^^^" '"te'^ t» the direct action of the 

ne Hould he a b.>ld man who w<.uhi account hy urh 
.^.-ences for the ditfererues of a dray and a r.u-e liors.' 
■ ^eo?i 7,' *';d Woo.! hound, a carrier and tumble; 
I .con One of the most remarkahle fealure^ in ou. 
o>mest,cc;ed races is that we ^e in them adap tion 

t" m nr; '" '^'; ■■^"""'■^^■'' *"■ ^'^^""'^ »-" ^^'^< •-» 

ue nroh.M '" •^""•'- .^."^ ^'^'•i-'tions useful to him 
■Z!;:::!'^."''^'' ^^,^^^\^-^y>or by one step; muiy 

:'*■,, ^•>"'^S.«''H-h cannot be rivalled by un^ 
"-.aauical contnvan.e. i« ouiy a variety of the wild 


iP, ov TIIR (iRKilX OF M'K( lh*s 

DipsaciiH ; ,ii;:i ttii-; ;it7)i>iiiit of cij<ir.i,'e may liavo sutl- 
tioiiJy arisen m a s.M'diinj-. So it iia- prohahly Ixhmi hIi}. 
tliM turn-pit doij ; ami :liis is known t<» liavo Ikm-ti liiu 
>j;i^(< witii *iit" an< (in sfuM']). Hut. wIhti ice compar" tiiii 
'lray-hor-»» a;.il racf-hdr-e, the (ironuMlary and canioi, 
tliy \ariiiiis i.rt'cii.s of -lieoj) tittcil pi^'wr tor cultivattMi 
lari'l i.r riii) [vsturc, wilti tlio wool vt ojie hroi'il 
.(to.l tor oiii- (iijrposri, an;l tfiat of another hreeii tor 
another |iiirtMi-(> ; '.vhen we rotnparo tlie many hree<l-; of 
~. each lio.iii for man in very dilfcn'nt wav^ ; w 'len 

' iiiparf the ^^arne-cork, so pertinario'i^ in liattle, 
'■"til nljicr lireeils so little (iiiarn'lsoriie, with ' over- 
■■• ii: layers' which never desire to sit^ and with 
:.,', hantain ~o r^rnall and eley:ant ; when wo eonipaio 
the h(;>t of ;u:ri(!illiiral, culinary, orciiard, and ilowtir- 
j:,arden race of plants, most useful to man at ditfcrent 
seasons and for itiifereiit purposes, or so h(!autif'i! iii 
his eyes, we niu>f, I tliink, look further than to mere 
variaifility. W'e cannot suppose that all the breeds 
•vere suddenly produced as perfect and as useful i;8 
we now see tiiein ; indeed, in several cases, we know 
that tiiis has not hecn their history. The key is 
man's jiower of accumulative selection : nature yives 
^iicce>--ivB variations ; man adils them up in certain 
directions uset'u! to him. In this sense he may ho said 
to make for himself useful hreeds. 

I'iie ;;rcat ['ower of this principle of selection is not 
hy]tothc ti<-a!. it, is certain lliat several of our eminent 
breeders (lave. tv--en within a sintrle lifetime, modified 
to a lari^e extent -ome hreeds of catti»i ainl sheep. In 
order tally to realise wjiat they liave done, it is 
aheost iicces'^ary to read several of the many treatises 
devoted to this suhject, and to inspect the animal.-t. 
Mreeders habitually speak of an anitrial's orj^anisation 
as >omethini; quite plastic, which they can model 
almost as thoy f)lease. If I had sj)ace 1 could (juote 
numerous p,a-sat:es to this etfect from hiirhly com- 
petent authorites. Vouatt, who was proliahly lietter 
ru-<)ua!!ited with the vvork.s of a^'-ricuituri.->ts than 
almost any other individual, aud who vvas himself j 


'Cry trood „f „„ arrliriaK ^(...aks of the j.nn.-iple ot 
'■i.vt;on as 'that «-),i,-h enahl..s the ai:rinilti,ri,.t, not 
:w_ to nuxiify the ci.aractfr of his /lock, huf to chant'*' 
.' alto-.-thor, Jf in the ina-ician's wan.i, hy rn-ans ui 
which he may s.irnmoii into life wh.levef tnrin and 
n.ouhl he i.ieases/ J.ord N)M.ervine. Kj-eakin- of 
what breeders have done for wlicej), savs :-' It would 
^■em ,-is ,f they had chalked out upon' a wall a form 
■ •TJrct in i(..,Mf, and then had pven it exi<tence ' 
1 .- :: most skilful hroeder, Sir John Sehriirht, u-t'i\ to 
say, witli resj.ect to jctreonfi, that 'he w.uild pro<iuc( 
atiy triven feather in tliree years, h^t it wul.; take hin, 
s.x y»>ar:, to ohuain liead and heak.' Jn S.ivonv t! .. 
imj)oriance of tt.e principle ui selection in rc-a'rd !,. 
iDeru.o .heep is >.o fully recn-nised, that nieii i,.ih)« it 
"^ '|, t;;"''*'- tJ'i- '^liwj. are placed (ui a t.ihle and are 
Mudii':]. like a picture hy a connois.-eur ; this i- done 
il.iec tunes at intervals of months, and the sheep are 
c.h time marked and clas-ed, so that tiic verv hest 
n:iy uuunatelv he selected for hreediiiir. 

U hat Ln-lish hreeders have actually etf..cted is 
['^'Y'" ''> ^'"* «^'i<»rmous j.rices jriven foranii,.aN with a 
irood podi-ree; and these have now heer; expert ed to 
f.lriM 4 every (juarter of the world, i he impn.vement i« 
t.v n,. means K«'nerally due to crossing differeiit hreeds • 
al, I tie he-t breeder, are stron^rly (.p{,o>ed to thi- 
i r.Kticc. except sometimes amont'st cl«.>.-lv aiiied suh- 
yreed^. And when a cross h.-s heen mad^. the closest 
MMecl,.,n IS far ,-,,ore indispensable e\ en than inordi- 
nary rases. If M'iection consisted nierelv in .MM)arat:nt: 
some very distinct variety, and hreediiiLr fro,,' it, ih. 
i'nncple ,w)uld he so obvious as hardly to he worth 
iH'tice ; but Its importance consists in the frreat effect 
pr<.(iiice<l by the accumulation in one direction, dunn- 
.Miccc.-,,ve generations, of differences absolutely itf- 
ai.j.reciaide hy an uneducated e\ e-ditlerences which I 
''^r „ne have vainly attempted to appreciate. Not one 

-.1 .'lent to become an eminent breeder. If irifted 
t these (qualities, and he studies his «ubject for 



yars, nrid rlevoto his llfi'tinif to it with indor.i.' iM« 
p«T .•\-r;iiico, 1h« will siiccoed, an.l wny make ^rcf 
:rnpr()> cuionrs ; if he wants ariv of' fhe^o (|ualitios, j.,. 
will n^Mirfvlly fail. Few wdiiM" roa.lilv holievo in tl'.- 
natural <-aiiarity aii<l years of" practico'reiiuisite to hr- 
come •■(.■M ;i skilTiil f<iireoi!-ta!icicr. 

I he .,-inip pru!cij)l(>s are followed hy horticulturists ; 
hut tlio variations are here often more al.rupt. \r» one 
-ui.po>es that our .hniccst ytroduitioTis ha\eheeri |>ro- 
dtjcod hy a -iiuis^p variation from tiie a'hoiitrinal >;tock. 
^^'e hiivr proofs tliat tliis is not -o ;?! some casos, in 
vv}ii<:h exact records have heen kefit : thus, to jriv'e ;i 
very fritlin-r ii!si;uice, the steadily-increa.-irnr sizo of 
tlie corniuon troosi-herry may he (';uoted. We see id 
astoni-niiii: in.provemeiit iii many fioriNts" fhnvcrs. 
when 'he t!<.wers of the present (hay'are compared with 
driW!i,os made only twenty or thirty vears airo. Whon 
■\ race of [daiits is once pretty w'eil cstahlishe.l. the do not pick out the'hest plants, hut merely 
an ow- tlM'ir -eed-heds, and pull up the ' ro:,Mu-^. as 
he\ call tlie plants that deviate from th.^ proper 
-laiidard. With animals tliis kind of sel'^'-ti,,,, is, in 
tact, also followed ; for hardly any one is ' careless as 
'o allow his worst animal^ n> hree'd. 

In rc-ard to plants, there i> another means of ol>- 
servin:; the accunnilated etlects of selccTion- nam»ly. 
hy comparin- the diversity of (lowors in the difrerent 
varieties of the same &perios in tlie tiower-trarden ; the 
diversity of leaves, pods, ..r liihers, or whatever part is 
val.M(!, :ii the kitchen-^Miden, in comjiarison with 
ti,e (lowers of the same yarieties ; and the diversity 
of fruit of the same si)ccies in the orchard, in com'- 
parison with the leaves ajid Hower- uf the same -^-t 
of varieties. ISee how different the leaves of tiie 
cahha-e are, and how extremely alike the flowers ; h..w 
unlike the fii.wers of the heart.sease are, and how alike 
the leaves ; how much the fruit of the ditlerent kinds 
of ^'ooseherries tlitfer in size, colour, shape, and liain- 
ness.and yet the riowers present very slifrj.tditierencM^, 
It is not that the varietjes whicli differ larjfely in son.e 



.au. m„nt .In ,mt riirer at all i,. „ ;„.r point, ■ thi- ,s 
nanllv ..v,.r. ,„.rh;,,,s rievor, tlio rase. lUv 'au. .,f 
c-..rn.Iat,o„ Of .^nr.vth, the importance of u In.!, sLniW,! 

ii''\er !io (iv^'fl,, 

;Nf'.l, will ensun> some fiifr.Tencfs ; (,,' 

ayi tron.rai rn.., I cannot donl.t that the confin,,...! 

>».'ic.tmn of si,.^„t variations, cither in the leaves the 

n...ers orthomnt, .ill pn.luce r... es .l,rterin,/ f'v ' 

each other chieflv in th<->e rharacters 

I^ mav he oh,cctecl that the principle of selection has 

;;V7':'r"' ";nH-tho.lical pra.t„.etorscan.elv„u.i 

tlian threo-.jiiarters ot a centwrv ; it has cerrainlV I m 

more att.r,.le.l to of late years, an,! manv tn^ri; ." 
U-en p.ihh.she.1 on the s„hiect ; an.l the result has heen 
m a .-orre^poiHiHiir fh-rce, raj,,,! an<i important lit' 

'li;<"verj I couhl ^,ve sovcral refercn.'e. to the f.,11 
..•Kmnvle.!,.,nent of the in.portance of the principle ;u 
v.r,... ;. n^^h antM,,my. In ru.lean.i harharons 
o. . u, hsh Instory choice animals wore often importe. 
.. a.s were passe<l to prever.t their'n : .1 nl 

HM.l th-s may he compared to the ' ro,n,in,r ' ot ,,i,,^^'^ 
y •'•--> n.en. The principle of selection 1 .in^ ^ 

■x. itTi" '" rr'r''' ''"""- encvclopa..,a. 
IjXF'lK, rules are laid down hy some of ll,e I omin 

h^..l wnters. From passa^e^ in (ienesis, \ttc^ 

tliac the colour of domestic animals was at that e- rh 

-rw>d to. now sometin;!!, rl"^, 

.'.sum. w.l.l cann.e animals, to unprovc, the hreed 

'" il'Mv. Ihe sava-es m South Africa nr'itch th..,r 

t','; u:,';;;"'of'", '■"'■""i "■^.■'" "■"■■• '-■"■'' i---.'x 

tnejr tiMm, of ili.irs. l.n,i,i.'«t.,i,o sl,„»s l„.» mr.l, 



ri.-id <|n;ilitit»s is so ohNimi- 

-\i til.' j.n'M-ut tiiiir. fu.iiHMit hic.vl.T- trv h- M.i.vtion, with adiMiiirt .,!,.■(•! in x„.\v to 
mak.' a ,„■« strain or s„|,-|iro,.,l, m,|.(m ,ur to 
exi^Mni: in th-- ro.mtry. J{„t. tor '.ur pu.pnso, a kind 
of N'|...t,oi,. vvlnrl. may l.o .alK'd lnro„.,-io,m, and 
winr . ros.ilt^^ fnuo cv-tv or,, trv.r.:: to ,,(.....,. and 
l>n'<-.l from the hp-t iiuiividiial an,r,ial<. il ..ore ini- 
p'Tlaril Jliiis. a man «|io in!.'n<!s k.'( pin- noint.Ts trie- lo trr! a«. i;,,.),! do.^. a^ ),.. ran. ar d aftor- 
waMis l.rtvd.. ir.,m hi> own Ih-1 .1..-.. i,.. Lhs no 
wi^ii or exportation o/ p.-rman-ntlv alL-rin- t),.. l.rood I raiuHd dout-t thai this,^ con- 
t:nu.Ml dhnno .H-nftirM>. «omoI nopnno a,nl modify 
i.'.v hroo.l. in th.. san,.. May as Hakcw.-li, ( ,dJ,ns, vlv\ 
■y tin. vory samo {.roro.s, only carried on more 
n.othndi.-ahy, ,\,,\ j^roatly moditv. even d.inn- thoir 
o.Mi JiUMime.s, tho forms and .jualitios of tlirir rattio 
^i<.^^ and inxMisddo cliaot^- of thi. kin.l could never 
t;.' reco-msed UMle^s actual measurements or careful 
<w•a^'Mur^ or ih,. l.rrvds in .jue-t>un had heen Ion- 
.-u:.., ^^l^.•h rn.:;hl serve tor companion. In sumerases 
lio^ever. unrhans:ed, or hut little chan-ed individual 
Of the .same hreed may he found in less <ivil,.ed dis- 
ti-ict-s. Where the hreed has heen less improved 'J here 
i> rea.on lu helieve that Kin^' fharlesH spaniel lias 
heen unconsciously modified to a lar^re extent since the 
tune ot that munar-h. Some hi-hlv competent 
authorities are convinced that the setter is directly 
derived from the spaniel, and has j.rohahly !„., n .«lowlV 
altered from it It is known that the Kn-li.h pointer 
has h.-cn ureatly chaiiired within the last .entury. and 
ni this case the chan-e has, it is helieve.i, heen chiefly 

etfeetedhvcr<.sscs with the foT-houn(l;),ut» hat concern, 
us IS, that the change has heen etfe.-ted unc.msciously 
and {rra.iuallv. and yet so etlectuallv. that, thouffii 
the old > pointer certainly came from .Spain Mr 
i.orrov, n.i. uoi seen, as i am informed by him! an v 
native Uof,^ in Spain like our p<dnter. 


"""Mers ;vitli the.f. f.mJ . ^'^^-^^'r^'^ «* carrior^ and 

thn„ih which tlC',;',^^ LShh":'^' T"*^ I''*' ^^'^- 

>n-o.listinct ra s^I^^^^^^^^^^^ 

^ept by Mr. li.ckley^nd mX ^^t^^ ".V;^-;:^- f'-'P 

marks, " iiave heen nurelv hr^J e^,,' *" •^''^- * ""att re- 

a s,i.,,„on existing i„ the nihKl of •"' ""' 

■''••l"ainted with the sub ec thJ th« ^^' ^ "" '■*' ^^^ 
them has deviated iu^f™r"''"/'"''^^'^^'«'"°f 
bJood of Mr. Swell "LT ""?'"' ^^^^ ^''« P"^e 
!^*'t«een the shVep rn'sissfd h ' ?l"^ ^f '^^ differL.ce 
^o trreat that thev h^vTtht ^ ^^ ''^^ gentlemen is 
•'.rterer.t varietie«-' ^' ^PPearance of bein^ quite 

of'tl!;;tSerS^r^f--« ? nevertothmk 
^••mestio animals vet anv nn^ «ff«Pnnff of their 

ful to them for 'uv sr^Zr '"""'^^ Particularly use- 

-ould thuTpeneralJv Wp'T ^"^^ ^'^"'^•e animals 

i"'V>rioroue«f so S in thir'""^ lf"^""^ '''^" the 

kin.i of !..:" w • '^'^'^ *''*"'« ^'ould bp a 

fi, ■ ••"••■"=«-. uas opic-riion iroin/r nr» w' 

fuino, bj, i,,^,^ |.,||^_^^^ ^_^ J devOLri„(f tli,.i ' 



old women, iu times of dearth, as or less value than 
tbeir doirs. 

In plants the tKime gradual procoHs of imjirovein«rril, 
throiitrh tlio ocrasional preservation of the Itest indi- 
viiluals, whether or not sudiciently distinct to be ranked 
at their first appearance as (hstincrt varieties, and whethei 
or not two or more species or race> liave become 
blended toi.rether hy crossing, may jiiainly l>e recojrnised 
in the incre;ised size and lieauty whu h we now see in the 
varieties of the heartsease, rose, pelart:oniiini,(h'ililia, and 
otlier planii^, when coni[>are(i witli tlie older varieties or 
with their parent-stocks. No one would ever expect to 
jfet a first-rato heartsease or dalilia from tlie see<l of a 
wild plant. No one wouhl expect to raise a tir:>t-rate 
nieltiiiL' jK'ar from tlie seed of the wild pear, thoiii^h 
he niitJ:iit succeed from a jioor seedling y:rowin^ wild, 
if it haii come from a trarilen-stock. i'iie pear, thoutrh 
cultivated in clas>ical times, appears, from Pliny's de- 
scripiioii, to have been a fruit of very inferior (jiialitv. 
I have seen preat surprise expressed in horticultural 
works at the wonderful skill of gardeners, in having 
produced such splendid results from such poor materials; 
but the art, I cannot douht, lias been simple, and, aa 
far as the final result is concerned, ha^ been followed 
ahnost unconsciously. It has consisted in always 
cnltivatiutf the l)est known variety, s(juin^ its seeds, 
and, when a sli;,rhtly better variety has chanced to 
aj)pear, selecting' it, and so onwards. Hut the 
irardeners of the classical period, who cultivated the 
host pear they could procure, never thoujjht what 
splendid fruit we should eat; thouijh we owe our 
excellent fruit, in some small detrree, to tlieir having 
naturally chosen and preserved the best varieties they 
could anywhere find. 

A lar^'^e amount of chan/?e iu our cultivated plants, 
thus slowly and unconsciously accumulated, exjdains, 
as I believe, the well-known fact, that in a vast numiier 
of crises we cannot recoirnise, and therefore do not 
knov\, Uie wild parent-stocks of the plants wiiicii have 
be«i?u longest cultivated in our flower and kitcheo 



^'aniens. If it has take,, centuries or tlu.usands of 
>.'ar>to improver modify m.wt of our plants u,. to 
tl..'.r pr.MM,t stan.iar.l 0/ u.Wulnes. to Lu, „, ' ...^ 
un.h.rsunul now .t 1. that neither Australia, the Cape 
«'f <-"»;l J Ope, nor any other ret,non inhai.Ue.i hv ..uitc- 
un.Mv.hse.1 man, has artonied us a sintrh- plant «rth 
'•ulture It ,s not that these i. h 
^p.-uesdonot hy a Mran^M, ehan.-e po^e^s the ahor 
.ma stocks ot any nsefwl plants, hut that the native 
i-mts have not hee:. improve,! hy rontinue<l sel vtVon 
"i. ^o a -lan.iard o. pertertion comparahle u ith th" 
.■iv.-.i to the plants u. <-ountnes anceutiv civilised ' 

In reirard to the do.nestic anunalskepi hv uncivilised 
-;-■"., .t should not he overlookci that they al m . 
aluayshave to struirt:le for their own food.' at "a, 
|:inn.^ cerum, seasons. And in two count ies e'v 
'i-'Vn.ntly circumstanced, individuals of the s^u. e 

?;;;■'.;" *''"'11 f'-^^'-'-^- •'■'•-^"^ constitution^ .r 
> ru.-ture would oflen succee.i hetter in the one countrv 
thru, in the other; and thus hy a process of ' Hat, .^i 
M-le.-t,on, as will her.vifter he' more fully exp ai led 
t->suh-hreeds mi.dit he forme.l. This, perhap , p '- 
evpla.n. what has heen remarket! hy Lnie'aL lori 
iK^mely that the varieties ke,,t hy sava^a,s have m" r^ 
ot the character of species than the varieties kei^ ,1 
civilised countries. ' '" 

« >'i the view here t^iven of the all-important part 
winch .election hy man has played, it heco ues It . mce 
ohvious how ,t ,s that our domestic races shuv^lda^ 
t.on m their structure or in their hahits to mans S 
.>r fancies. U e can 1 think, further understand le 
.*re.|uently ahnormal character of our domesti ra<'e 
■^'"i likewise their differences hein-^ so .^reat i.i exte rai 
' haracters and relatively 80 «]i,.ht in internal ,'irts or 
orjrans. Man can hardly select, or only w I ";;,,' 
d.lhculty. any deviation of structure ex.-eptin^ such Is 
u^ externally vu^ihle ; and indeed he rarlly l^r!^^ 
-^^a. ;^ iiiternai. He can never act hy selection ex 

^me =,l,ght degree by nature. No man would ever tn- 




to make a lanfiil, till he saw a pij,,.,,,, with i tail 
developed iii >,„ne sli-ht df^rreo in an -inusual manner 
or a pout.'r till ho saw a pi-eon with a rrop of som.-uhit 
unusual s]/.e ; and the more ahnorinal or unuMial any 
rharacter was when it first appeared, the more lik.-lv i't 
would ho to catch hi.satt.-ntion. Hut to une su,h'a-> 
ivvpn'-siuri a.^ tryiii;,' to make a fantail, is i )iave -lo 
d')u,.t, u, most eases, utterly incorrect. Ihe man ^^ ho 
first Mi.Tt.Ml a pi-eon with a si■^^htlv lar-er tail, ne\->r 
drear ed what the descendants of that pi-eon woiild 
become through lontr-continued, partly unconscio,i.s 
and part y n...tho,li,aI .election. I'erhap. the parent 
l.r.l of all tanUils had only Jo.jrteen t^iil-feathers some- 
what expanded, like the present Java fant^iU, or like 
individuals of other and distinct breeds, in which as 
many as seventeen tail-feathers have been counted' 
I eriiaps the first pouter-pi <reon did not inflate its croo 
much more than the turbit now does the upp.-r part of 
.te *sophairus,-a hahii whicli is disre^rarded by all 
taiT.;crs as it is not one of the point* of the breed' 

^or let It be thoufrht that some preat deviation of 
structure would be necessary to catch the fancier's eve- 
he perceives extremely small differences, and it is in 
human nature to value any novelty, however sli-ht iu 
one 8 own possession. Nor must the value which would 
formerly be set on any sli-ht difTerences in the indi- 
viduals of the same species, be judged of by the value 
whi.h wouhl now be set on them, after several breeds 
have once fairly been established. Many slight ditler- 
euces miKnt,and indeed do mow, arise amonirst pi>eon« 
which are rejected as faults or deviations from the 
standard of perfection of each breed, 'i'he common 
^oose has not KJven rise to any marked varieties ; 
hence the 1 hoiilouse and the common breed, which 
differ onlv m colour, that most HeetinK of characters, 
have lately been exhibited as distinct at our poultry- 
shows. *^ •' 

I think these views further exnlain what has -"-^-. 
times i,een not.ced-namely, that we know notliiiu' 
about the orif-iu or history of any of our domestic 

7^ ^.r^^^^^^^«I^^*??] 


breed.. lUa, in fact, a bree<l, like a ,J,.dert of a 

lar..r„ape, can I.. „aid to have ha.l a .iefin te 

.- nr. A man , esorves .nd bre< ,1s from an ir.di'n d 

« :1. .ome si-,. hi deviation of structure, or Uke n e 

.nretuan usual ,n mat.lm,,. Ms Lost anirnal'ami thu" 

-proves u.e:n, and the irnprovod individual, so.h 

THMd n the nnmed.ate nei^^hhourhood. J{ut al vet 

•-.;> -.11 hardly have a dist.n.t nan.e, and from^,^^^^ 

on y >h,.ht Iv valued, their history will he dJe^Zl 

I>-..ewM, they ndi spread m„re widcdv, and will -et 
e< ..nnsed a. ».>n,ethin.. distinct and valuable, and vT-l 
.en i.rr.hahly nrst receive a provincial ,.an.e. In sen.'-.d countnos, with hftle free^tion 1 1. 
^pre..,l,n^ and knowled,.- of any new .ul, hreedJil . 
« ..h>. process A. soon a. the poinUs of val'e o ^ 
:..- suh-hre.d are once fully acknowled^^ed. the or n 

■ i *®"' i ~ '"'''-^PS more at one period than at 
a.-other, as the Ireed riMen or falls in fashion. ;' ar! in one district than in another, accord ,..i t^^ 
. .teofc.v.l,s.Umn of the inhahitan'ts- to add 
- the character.sfc features of the breed, whate^'er 
-y may be But the chance will he inrin lel hh nl 
..f any record havmg been preserved of such Xw 
>aryin^, and insensible changes ' 

I n.ust now say a few words on the circu -..stances 
favourable or the reve^.e. to man's power ot locUon 
A )u,h de.^ree of variability is obviously favourable^ 
fr. ely p,v,ng the materials for selection to work on 
uot that mere individual differences are not amn^' 
-mcient, with extreme care, to allow of the°u cur^uk 
^on of a lai-Ke amount of modification in a n',^? an" 
•lesired d,rectu,n. Hut as variation, manifestl "If^^ 
u p easing to man appear only occasionally, the chance 
-f their appearance will be much increa.sed by a ar^e 
numher of individuals bein^ kept ; and lice "hi! 
•■•:.- ^ !^« o^ti^ie hisfhest in.j,o-tance to succe«i^ On 
- principle Marshall ha.s remarked, with res.Lt 
^.- =heep of part« of Yorkshire, th.t U they .^eirerau' 


!'»'loiiir to jHior [)»•(. pic, ami .iro nio-Mv in uvuill /o/*, 
thfv ii.'ver r-;iii })« im_irov»><|.' On tlio otlicp }|!iTid,' 
niir-iTvnuMi, fnun raivirnr l.-irtrn sfo. k-> of tli»> vame 
pl.iiits.are yenpraily far morp siiccp^^ful Hiari aiiKit.Mirs 
in trettiinf now and valnal.U? varieties. I lie ke<>[»ini,' of 
a;:(> iiurii'MT of itii|i\ idiials of a -Ji-ecieH lu aiir 
coiiiitrv re(|iiire<j t}iat tlie specie^j sliould Ko plared 
under favonraMo coiiditions <»f life, ho is to hrcM freelv 
in that cotmtry. ^\ lien th*> individua!-' of any species 
are scaiitv. ;ill tlie individuaU. wdatever tlieir quality 
niav he, will .generally ho allnvred to hreed, and this 
will etfecttrilly prevetit sel.ction. Wnl Mie 
most ini|.<>rtant pcint of ail is, that tile animal or 
plant should Im. so lii;.r|,ly ;,spf,jl to man, or so miirh 
valued hy him, that the closest attention should he paid 
to even the sliirjitest deviation in the (jualities or 
structure of each individual, rnless such attention he 
paid tu'thin^' can t.e etlected. I liave seen it uT-ivelf 
rerTiarked, that it was mo>t fortunate that the">traw- 
herry hej.'-.-in to varv just wlien trardeners h««:ran to 
attend closely trj this plant. No douht the strawherrv 
had ainays varied -ince it was cultivated, hut the shVht 
varieties had lieen tiet^Ierted. As soon, however, as 
^rirdeners pi-kcl ..ut individual plants with sliurhtly 
I.'irjrer. earlier, or Letter fruit, and raised seedliriir's 
from ther>' and aj-ain picked out tlio hest seedliiiirs and 
t red t'rom them, then, tl, ere appeared (aided hy so-ne 
crossiii^r ;vit)i distinct species; those rjianv admirahle 
varieties of tlie strawherry wh'ch have heen nii^.'d 
duriiiir die !'i>t thirty or forty years. 

In tiic -^i-se of animals vvith separ.te sexes, facil'ty in 
pre-iMai- ir cnx-os is an import;int element of success 
Ml the f.M-inatio'i nf new race-,— at lea>t, in a country 
which ix already stocked with other race,«. In this 
resftect enclosure of the land [>iays a part Wandering 
■Miva:res or the inhahitant.s of open plains rarely possesa 
more tlian one breed of the same species, ri-reoiis can be 
m.iteil for lite, and this iit a irroat ccnveriience. t.o th« 
fancier, for tiius many races may he kept true, thouiih 
miKjfled in the same aviary ; and this circum.stance 


must h.ivo larn-plv favoured tho impnivernent and 
foniMtiun of new l.rep<ls. l*ii:<'oiis, I may a<i«l. cin l<« 
pr«.|.a(.Mt«'il in trn-at miml.ors riiKi at a vrry quit k rate, 
and iiifcridr hinisniayhe freely n>iprted, as when killed 
thev nerve for tiKMJ. On the other hand, cats, from 
their nocturnal ranildijit' hahits, cannot he matched, 
■itkI, a]thou{:h so much vahied hv«(.men and children, 
we hardly ever nee a diMtin<t' hreed kept up; mich 
breeds as we do sonietirneM see are almost always im- 
ported from some other country, otlen from is'laiulv 
Althoiii:h I do not douht that s<.me domestic animals 
vary less than others, yet tho rarity or ahsence of 
distinct breeds of tlie cat t>'e donkey, peacock, iroose, 
etc. , may he attrihuted in iMain part to selection not 
haviii,^ heeii hrouir'.t into play : in cats, from the dith- 
cilfy in pairing tliem ; in (h.nkevM, from only a few 
heiii!; kept hy poor people, and lit'tle attention 'paid lo 
their hre«'diiijr; in t>eacockH, from not heiiitr very 
easily reared and a lar^e stock not ke|.t ; in fcree<e. 
from hein^r valualde only for two purpoM's, food and' 
feathers, and more espeeiallv from no pleasure havin^r 
l-een felt in the display of distinct hreeds. 

losiim lip on tho or!::in of our l>..mestic Haces of 
animals and plants. I helieve that tiio conditions of 
life, frr)m their action on the repr()ducti\o sv^tem, are 
so tar of tlie hii^liest importance as ca.isin:: variahilil y. 
! 'lo not helievp that variability is an inherent and 
ii^-^'cssary contin;(en<"y, uiuler al'l circumstances, with 
il! ortranio ^jme authors have thoii-ht. I he 
•••fects of variability are uuuiified hy various de:rrees .,f 
nihcritance and of reversion. Variability is 450%. •rued 
by many unknown laws, more especially by tliat ot cor- 
relilion of ;:rowth. Something-- may be attributed to 
'h>' direct action of tlie conditions of life. Sr.metliinw 
'ti 1st 1^ attrihuted to u.<!e and disuse. The final re-ult 
in thus rendered infinitely complex. In some r-.^M, I 
do n(.t doubt that the i..tercrossine of Hpecien, ahori^ria. 
■ -ly -listiiict, li.t.-, piayeu an important part ui the onirm 
"f our domestic productions. U lion in ariv country 
several doinetitic breeds hare once been ertablished, 




tlieir occaninnal iiiterrros«iruf, witli tlif» aid of m-lertion,, no (loijlit, lartroly ai'ini in tJie fi»riii;iti()ii of new 
Kiih-lireeds ; but tlio iiiiinirtanco of ll<n rrosxintf of 
varieties has, I believe, been jrre.itly ex.-iirtrerated, Itotli 
in retrard to aiiinuils and to tlio<ie jil.ants wliidi are 
|iroi>i::iited by need. In plants wbicli are temporarily 
prnpau'stted by cuttintrs, buds, etc. , tlie imrmrtance of 
tin' iro-.sin(r botli of di-itinct sperien and or varieties !► 
immense; for tlie rultivntor liero quitu di-jreirardH ibo 
extreme variability both of liyltrids and nion>i:rels, and 
tbe frerjiient sterility of bvbnds ; but tbe < ase» of 
plants not projia^Mteil by seed are of little importanc. 
tf us, for their endurance Ik only temporary. Over all 
the^e causes of ( baiitre I nm eonvinied that tbe 
a< i-unnilative action of Selection, wbether apjdieii 
m. tlioflically and more quickly, or uiiconscitmsly and 
mure slowly, but more efficiently, ia by far tbt* prt- 
doininant I'owor. 



' '''''"i'y-.J'""*i'l""!'l'tr<r-iM- I...ulitful,,HH-le.- WMrrun^n. 
-'u:h .li.I,..s.-.l ai.a ,„.imi.,„ „„.,.„., var> ,Mo»t- >i.. • i., „f ih; 

vwru-iicg ir, l,Wn« very d,.«Wy. hut uue-iualiy, f.iuU.l t.. „^h 
•UitT, and in iiav.i,^' rtslri..i, ; i.^.^j,-,*. 

Hkm)hk aj^plyini; li„, pridciplos arrive,! at iii ine Um 
. naptor to or^.iiih l.eiiiK> ii) a stile of naUiv", we n, ,.t 
i.ii.-M\ ,lisrii>~ vvlu-ther tlu-so lattt-r ar., sul-.f.-t to ,iii\ 
Narial.oii. "J o treat tl.i^ sul.ject at all pru|M'riy, a Urn. 
< ..■' n^r,H. of dry farts shoiil.l bo u^^vu ; Init tlu-.e I 
'•fi.iii ri-M,rve fur my future work. \(,r shall I here 
(liM-uss the various defmitioiis whicli have he.ii i,M\eu of 
t,iL. tonn ' species.' No ojie delinition has iis yet Kati.stied 
ah ualiiranfs ; yot every natiiiaiist kiioxvs vaiznelv 
v^ hat he meai.., when he sj.eaks of a soccu-^. ( Joiier .11 v 
tuu term includes the unknown elerV.ent of a di.sUnct 
a,t of creation. The term ' vanotv ' is almust equally 
MthcuJt to define; but here community of de^.ent in 
almost universally implied, thou-h it can rarelv he 
! rovo.l. \\ e have also what are called mon>trnsui.-s 
I'.t t.iey ffraduate into varieties. By a monstrosity 1 
iH-Mime IS meant some considerable deviation of 
-uu.ture in one part, either injurious to or not u.-4ofui 
.0 llie species, and not generally prop.i^raie.l. .Some 
a ithors use the term 'variation' in a te.hiji. a] 
n,;il\'ino- a n!odiH;-.-t!.--r-. 

ci-!.ditions of life; and 

Hupposed not to be inherited: but wh 

sense, as 

liuc lo tijc piiv>.cai 

variations' in this sense are 

o t'-au r«a\ that tlu 





(iwarfrd conflitio'i of slielN in the }ira<'ki>h waters of 
tiie I'.i'tic, or (iuvirfed [li.iiils on Alpiri" •iiirruniL«, or 
the thirkpr fur of an animal t'roin far tiorthwanls, would 
not in soMio rases he inheritoil for at least some few 
ireu'Tations r and in this case I tiresunie tliat the form 
would he called a variety. 

Airain, we have many slit'^ht dilTerenoes which may 
he called mdivirlijal differences, sin-h as ara known 
fre<]iiently to ajiiicir in the olf-prinir from the 
s;inio parents, or wliich may he presumed to have thus 
arisen, from hein^ freciiiently ohserved in the indivi- 
duals of the same species inhahitin»f the same confined 
locality. N'o one supposes that all the individuals 
of tlie same species are cast in the very same mould. 
These individual differences are hifrhly important for 
us, as they afford materials for natural selection to 
accumulate, in the same manner as man can accumi- 
lafe in any yiven direction iiulividual differences in his 
dc)mestic^ateti productions. 'Hiese individual differences 
?onerally affect what naturalists consider unimportant 
[wirta ; hut I could sliow hy a lonfj cat.iloirue of facts, 
that parts which must Vie called importdit, whether 
viewed under a physiolojrical or dassific-atory point of 
view, sometimes vary in the individuals of the same 
specii's. I ain convinced that the most experienced 
natu'-alist would Ini surprise<l at the numhcr of the cases 
of variahilit> even in importmt parts of structure, which 
ho coulil collect on ^ood authority, as I iiave collected!, 
diirin:; a course of ye^'irs. It should he rememheied 
Uia*- systematisfs are far from pleased at finding' varia- 
bility in important characters, and tliat there are not 
many men who will la!H)rii isly examine internal and 
iniporlHiit or^rans, and compare them in many speci- 
mens of the ivjime specip«. I sliould never hav»i exfH^cfeil 
that th« hranchintr of the main nerves dose to the a^reat 
central irauirlion of an iu^ect would have hecn variahle 
in the same species ; I should have expected that 
chan^^es of tins nature couid have been effected only 
by slow dci^r'^es : yet (juite recently Mr. Luhhock has 
shown a detfree of varialiility in these main nerve* 


hi CocciiP, winch may ainjost be compared to the 
irrPiruI.-ir branrhino: of the stem of a tree. Tliis 
phil.mopbical naturalist, ! may add, has also quite 
recetitly rthnwri that tlie muse Ips in the larvte of cert^iin are very far from uniform. Authors sometimes 
artrup in a rir.le when they stMe that imi>ort;int ortjans 
never vary : for these same authors practically rank 
that character as important (a-- some few naturalists 
have hone-tly confessed) which does not vary ; and, 
iiiider this point of view, no instance of an important 
part varyintr will ever be found : but under any other 
point of view many instances assuredly can l»e tr'iven. 

There is one point connected with individual differ- 
ences which seems to me extremely perplexinjf : I refer 
to those e^enera which have sometimes been called 
'prolean' or 'polymorphic,' in which the specie* 
present an inorditiate amount of variation ; and hardly 
two naturalists can a^ree which forms to rank as 
species and which as varieties. W'e may instance 
Kubus, Kosa, and Ilieracium amonp^st plants, several 
penera of insects, and several jrenera of llrachiopod 
shells. In most polymorj>hic (genera some of the 
species have tiied and definite characters. (Jencra 
which are [»olymorphic in one country seem to be, with 
some few exceptions, noivmorphic in other countries, 
and likewise, judjrintr from Hraciiiopod shells, at former 
perio<ls of time. These fa.-ts seem to be very per- 
plexinif, for they seem to show that this kind of vari*. 
Julity ifl kndej.endent of the conditions of life. I ..m 
inclined to suspect that we see in these polvmorphic 
j:enera variations in points of stru.ture whi.h are of no 
service or disservice to the species, an.l which con- 
W'l"«""tly ha%e not been seized on and rendered 
dehmte by natural ^election, an hercifter will he 

Hiose forms which possess in some considerable 
desrreo the character of species, hut w.iicb ar^ qq 
cirw-eiv similar to some other forms, or are so closely 
hnked to them by Intermediate tfradations, that 
oaturaDsts do not like to rank them as distinct specieii, 




arp in several respects the most important tV)r uii. We 
have every rcison to believe tliat ma/iv of thesf 
ddiilaful and closely-allicii forms have jierniaripntly 
retiiried their characters iu their own country for a 
luiiiT tirrifc) ; for as InufX, as far as we know, as liave 
f<-()0(i and true species. I'ractirally, when a naturaiisi 
can iiuito two forms toffeLher hy others havintr inter- 
mediate characters, he treats the one as a variety of 
the other, ranking? the most common, but sometim* t 
the one fir-^t dn-crihed, as liie specie^, and llie other as 
♦}i*' variety. But cases of creat difficult;,, which 1 will 
not here enumerate, som -times occur iu dt'cidiu^' 
wliether or not to rank one form as a variety of 
another, even when they are closeh conmclcd by 
■ nteriiiediate links; nor will the commonl} -.i^samed 
hybrid nature of the intermediate links alwavs reuiovt 
the difficult/. In very niariy ca-cs, however, one form 
in ranked as a variety of mother, not because the 
intermediate link.s have actually been found, hut 
i.ecause analoiry leada the observer to supjiose either 
that they do now somewhere exist, or may formerly existed ; and here a wide door for the entry of 
doubt and conjecture is opened. 

Hence, in determining whetlier a form should be 
ranked as a species or a variety, the opinion of natural- 
isLs having sound judg-ment and wide experience seems 
thi' only guide to follow. We must, however, in many 
ca-e«, decide by a majority of naturalists, for few well- 
marked and well-known varieliejj can be named which 
have not been ranked as species by at least ome com- 
p. tt'Mt judfres, 

■J'hat varieties of this doubtful nature arc far from 
uncommon cannot be disputed. Compare tlie several 
floras of Great Britain, of France, or of the United 
i>t.ites, drawn up by different botanists, and see what 
a surprising number of forms have been ranked by one 
botanist as good species, and by another as mere 

:_i: — ^f _ II f> ii-_* ., -. i - _u-_- r i! _ - i i 

ra;ic.:t--. .rii. a. \ , TraL.-i;;;, la ~ livTli i lie L.n.'iCr UCCp 

obligation for assistince of all kinds, has marked for 
me 182 Briti^V plnnls, which *re generally considered 



US varieties, but which have all hoeii ranked by 
botinisU as specit-.s ; and iu makiuu-- this list he haa 
■Miiitted many tridiufr varieties, but which U'jverth.'I.-^s 
h^ive been ranked by some botanists as species, ami he 
iias entirely omitted several hiifhly polymorphic p-c:i.Ta. 
' n-Urr g-enera, includinor the most polvmorphic f..; ins 
Mr. lial.intrton gives 251 species, wlierea.s Mr. J5en' 
•ham gives only 112,-8 difference of l.'W doubtful 
forms I Amongst animals which unite for each birth, 
and which are highly locomotive, doubtful forms,' 
ranked by one zoologist as a species and by another as 
a variety, can rarely be found within the same country, 
but are common in separated areas. How many of 
those birds and insects in North America and Europe 
which ditfer very slightly from each other, have lieeu 
ranked by one eminent naturalist as undoubted species, 
and by another as varieties, or, as they are often called' 
asgeograpliical races ! Manyyear8a{.'o,when comparing* 
and seemg others compare, the birds from the separate 
Islands of the Galapagos Archipelago, both one with 
another, and with those from the American mainland, 
I was much struck how entirely vague and arbitrary 
18 the di.stinction between species and varieties. On 
the islets of the little Madeira group there are many 
insects which are characteriged as varieties in Mr. ^V^)l- 
laston's admirable work, but which it cannot be doubted 
would be ranked as distinct species by many entomo- 
loirists. Even Ireland has a few animals, now generally 
regarded as varieties, but which have been ranked 
IS sj)ecie8 by some zoologists. Several most e.vt)erienced 
ornithologists consider our Hriiish red jfrouse as only a 
^trontriy-marked race of a Norwegian species, where;i8 
the greater number rank it as an undoubted species 
I>ecuiiar to Cireat BriUiin. A wide distance between 
the homes ©f two doubtful forms leads many naturalists 
to rank both as distinct species ; but what distance, it has 
been well asked, will sutlice.^ if that between America 
;;;'i nurope ih Hinpi,., will that between the Continent 
uid the .A/ores, or Madeira, or the (anaries. or Ireland 
« sufficient ? It must be admitted that many forms' 



eonsidered by bifjhly-irompetent jiidfrf^' as varieties, have 
so perfectly tbe character uf species that they are ranked 
by otlier hitrhly-coinpetent jud^^es as good and true 
species. But to discuss whether they are rightly called 
species or varieties, before any detiiiition of tiiese terms 
h;is been peiierally accepted, is vainly to beat tiie air. 

Many of the cases of stronfrly-niarke<l varieties or 
doubtful species well deserve consideration ; for several 
iutercstinj^ lines of arffunient, from treotrraphical dis- 
tribution, aiialofjical \ariation, hybridism, etc., have 
been l)routrbt to Itear on the attempt todetermine their 
rank. 1 will here jfive only a single instance,— the 
well-known one of the primrose and cowslip, or 
I'rimula viiliraris and veris. These j)lanls differ con- 
sideral)ly in appearance; they have a diJerent flavour, 
and emit a dirferent odour ; they llower at slightly 
dirteient periods ; they grow in somewhat different 
stiitions ; tiiey ascend mountains to different heights ; 
they liave different geographical ranges ; atid lastly, 
accorduig to very numerous experiments made durifig 
several years by that most careful observer (iartner, 
they can bo crossed ofily with much difhculty. We 
could hardly wish for better evidence of the two forms 
being specifically distinct. On the other hand, they 
are united by many intermeciiate links, and it is 
very doubtful whetlier these links are hybrids ; and 
there is, as it seems to me, an overwhelming afuount of 
exp«'riinental evidence, showing that they descend 
from common jtarents, and consetjuenily must be 
ranked as varieties. 

(lose investigation, in most cases, will bring natural- 
ists to an agreement liow t > rank douhtiul forms. Yet 
it must be confessed tha, it is in the best- known 
countries that we find the gre;itest number of forms of 
doubtful value. 1 ha\e been struck witli tlie fact, tliat 
if any animal or plant in a state of nature be highly 
useful to man. or from any cause closely attract his 
attention, varieties of it will alsiiOst universally 1>6 
found recorded. These varieties, moreover, will be 
often ranked by some authors as spe<Mos. IawU. at th« 



eommon oak, how closely it has been studied ; yet a 
(iernian autlior makes more tliaii a dozen 8j)e«-'ies out of 
forms, whic-li are very generally considered as varieties ; 
Hud in this country the highest hotanical autliorities 
and practical men can be (juoted to show that the 
he>sile and pedunculated oaks are either good and 
di•^tiIlct species or mere varieties. 

W hen a younu' naturalist commences the study of 
a trntup of orffanisms quite unknown to him, he is at 
first much perplexed to determine what diriVrences to 
consider as specific, and what as varieties ; for he 
kn(»rts notliintf of the atnimnt and kind of variation to 
which the yroup is subject; and this shciws, at least, 
!iow very t^eneraHy there is some \ariation. Hut il he 
(•online his attention t<» one ■' v.-.s within one countrv, 
be will soon make up his mnid how to rank m<»«.t of 
the doulitful forms. His jfeneral tendency will le to 
riKike many species, for he will become improved, just 
like the pijreon or poultry fancier before alluded to, 
^^ilh tbe amount of ditlerence in the forms which he 
!s continually studyintr ; and he has little peneral 
knowlt'djrj of analo^'iral variation in other groups and 
11. other countries, by which to correct his first im(»res- 
> >:i>. As he extends the range of his observations, \w 
will meet with moro cases of difficulty; for lie will 
tiuounter a greater numl)er of closclv-allied forms. 
Hilt if his observations be widely extcn<led, he will in 
tiie end generally l»e enabled "to make up his own 
mind wiiich to call varieties and which sjte.ics ; but he 
will succeed in tliis at the e.vpense of admitting much 
variation, —and the truth of this admission will often 
l>e disputed by other naturalists. Wben. moreover, lie 
■omes to .study allied forms brought fnun countries not 
now continuous, in wbiih case he can banllv hope to 
rlufi tbe intermediat«> links between his doubtful forms, 
iie will have to trust almost entirely to analogy, and' 
his diificiilties rise to a climax. 

V r. uijiiij iir, i icar line oi deniaicatioii haii as yet 
been drawn between species and sub-species— that is, 
the forms which in the opinion of some naturalist* 



ror'ie very noar to, tint do not quite arrive at the 
ruuk of" spt'cit's ; or, a^.iiii. betweori sul>-spooies ami 
vc«'ll-inarkf(i varieties, or l>etwiHMi !t,'-<sor varieties and 
iii<iivi(Jii;ti <lirtereiK-es. i'liese ditfereiiees blend into 
•«irli «itlier in an insensible series ; and a series im- 
j)resses tbe mind with llie idea of an actual passaije. 

Hence ! look at individual ditferences, thouijh of 
small interest to the systematist, as of hiirh importance 
for IIS, as bein^ the first step towanls sucii sli^'bt 
varieties as are barely thou;: lit worth recording; m 
work* on natural history. And I look at varieties which 
are in any de:,nee more distinct and permanent, as steps 
leadi!!::^ to more stron^lv marked and more |)ermanent 
varieties ; and at these latter, as leading? to sub-species, 
and to species. 'Hie pa^ssafje from one sta^e of ditl'erence 
to another and higher stage may be, in some cases, 
due merely to the long-contiinied action of different 
physical conditions in two different regions ; but I 
riave not much faith in this view ; and I attribute the 
passage of a variety, from a state in which it differs 
very slightly from its parent to one in which it differs 
more, to tlie action of natural selection in accumulating 
(as will herejifler be more fully explained) differences 
of structure in certain definite directions. Hence I 
believe a well-marked variety may be called an in- 
cipient species ; but whether this belief be justifialde 
must be judged of by the general weight of the several 
facts and views given throughout this work. 

It need not be supposed that all varieties or incijiient 
species necessarily atUiin tlie rank of species. lliey 
may whilst in this incipient state l>ecome extinct, or 
they may endure as varieties for very long periods, as 
has been shown to be t!ie case by Mr. U'ollaston with 
the varieties of certiiin fossil land-shells in Madeira. 
If a variety were to flourisli so as to exceed in numbers 
the parent species, it would then rank as the species, 
and the species as tlie variety ; or it might come to 
supplant and exterminate the parent spe«'ies ; or both 
niiirlit co-exist, and both rank as independent species. 
Hut ^e shall bcreiifter have to return to this subject. 


From llie^P remarks it will h«. ,..,,„ tliat I In.k it 
•)io term .pecios, as one arbitnuily ^nven for the sake 
■.f c-otiv,.„,ei.ce t.) a set of in.lividuals oloselv re<...nil.lii,.r 
".i' M other, aiKi that it docs not ossetitiallV (lifrnr fr..-M 
he term variety, uliich is trive.i to less ".iistiiict a,.] 
^u„e HurtuatMi^r forms. The term va ietv, Htzrin in 
".t„,,;ins(m with mere indivi.l.ial ditTen-nVes, is a].,, 
Hn.iied arl.itrarily, and f(»r mere convenience' sake. 

'.luded by theoretical considerations, I thoiit^lit that 
>o'ne intorestinif resnlts mi-ht he <.hfiined in re-a-d 
to tlie nature and relations uf the species whi.di vnrv 
most, hy tahiihitiiiir all the varieties in several welf- 
worke.l floras. At rirst this seemed a simple task ; hwt 
• V; • ;\*'*^'^«"' to «••">"! I am much indel.ted for 
v.Mial.le advice and assistance on this snhject, soo„ 
.'ouvinced me that there wore many difficulties, as did 
^iif'so.,.,ently Dr. Hooker, even in stronjrer terms. I 
shall reserve tor my future work the discussion of 
these difTi.Milties, and the tahles themselves of the pro- 
pcrtional numhers of the varying species. Dr. Hooker 
[permits me to add, that after having carefully read n.v 
'ninuscnpt, and examined the tahles, he thinks that 
the to low.ngr sfitements are fairly well estal.lishe.1 whole subject, however, treated as it ne<-essarilv 
here 19 with much brevity, !» rather perplexing, and 
ahusions cannot he avoided to the 'stniirile for exist- 
ence'duerpnco of character,' and other questions, 
hereatU'r to he discussed. 

Alph. de Candolle and others have shown that plants 
••^hu-h have very wide ranges generally present varieties ; 
in<l this might have been expected, as they l,ecome 
'■X posed to diverse physical conditions, and a« tli..y 
•oM.o into competition (which, as we shall hereafter see, 
N a tar more important circumstance) with different 
-ets of organic beings. Hut my tables further show 
Uiat m any hrnited country, the species which are 
must common, that is abound mo^t ir, i.wjjyM....) . „j.,i 
aie species which are most widely diifused' within thVir 
<nvM country (and this is a different consideration from 
•n.le range, and to a certain extent from common nasa) 





i)*!oii eive rise to varieties KuiTiciontly well marked to 
K.'se heeii rertudcd in lujtaiiical works. Hence it \*> 
tii»' niK^t fiiturihhin^, or, as they m.'ty !«' called, the 
lotiiiuant species, — those which raiitre wid»>]y over the 
woilii, are the most tlitiu^ed in thiir own country, and 
are the numerous in individual^, which oftenerft 
produce well-marked varieties, or, ius I consider them, 
iiici|iicnt species. And this, jM-rhaps. iniuht iiave ht'en 
anticipated ; tor, as \arieties, in order to tecorne iu anr 
(le;jree permanent, necessarily have to strutrtfle with 
tlie ollit-r inhahitiints ot the C' intry, the species which 
arti alnatly dominant will he lit- most likely to yield 
otisprinL'. which, thoiit;li in some slijfhl decree modi- 
;u(l, still inherit tlii>se a<lvanta::e.N that enabled their 
[)arent.>- to hecome dominant over their com[(atriota. 

If the plants inhahiting' a country and descrihed in 
anv lloia he divided into two e(jual masses, all those 
in the lar^rer yenera heintr placed on one hide, and all 
tho<e in the smaller genera on the other side, a some- 
i> liat lar;rer numher of the very common and much 
|l!tlll^ed or dominant species will he found on the side 
(.f the larjrer genera. 'I'his, ;i{;ain, miiiht have been 
anticipated ; for the mere fact of many specie.« of the 
s.ime ^enus iiihahitiiiff any country, shows that there 
i> sotiiethinf; in the or;ranic or inortjanic conditious 
ui thai country favourahle to the trenu.- ; and, conse- 
quently, we mif;ht have expected to have found is 
tiie lart^er ^'•eiiera, or those includmjj many species, a 
larire proportional numher of dominant sjiecies. Uut 
•■o many causes tend to obscure this result, that 1 am 
surprised that my tables show eveii a ^mail majority 
on the side of the lartrer jjenera. I will here allude 
to only two causes of obscurity. Fresh-water and salt- 
lovinir plants have generally very wide rariijes and are 
much (htfuaed, but this seems to he connected with the 
nature of the stations nihabited by them, and has little 
or no relation to the size of the <renera to which the 
gpecioH tieiong. Ap^ain, planum low in the scale of 
or^anis^ition are generally much more widely dilTused 
than plants higher in the scale ; and here agaiu there 


f no rlnso relation to the RJze of tlie Kf^'iera. Jhe 
r.TiiHeof Iowly-or;r;ttiised plaiita raii^riiur widely will be 
J.M ussed in our cliapter on ffeo^rraplii.-al distn'hution. 

1 rom lookintf at epccies as <,uly Htronuly-niurkfd 
aiMl wvll-dt'fuied vnrietii's, I waa led to anticipate that 
lh»' species of the l.irtrer ^'cnera in each rountrv would 
u/i.'ner present varieties, than the 8i)e<ies of the Hmaller 
►T'-nera ; f<»r wherever many closely-related specie* (i.^. 
-p-cies of the s.irne jfenusy have'hocn forn>e<l, m.-uiv 
varieties or incipient soecies ouiclit, a« a ^a-neral rule, 
to he now forming. Where many larj^e trees trrow,' 
wfc expect to fnid eaplinjfg. U'he're many specieM of 
a jeuus have been formed throut^h variation, circum- 
Htauces have heen favourable for variation ; and hence 
we initrht expect that the circumstances would jfenerally 
be still favourable to variation. On the other hand, 
if wc look at each species as a sjKicial act of creation,' 
there is uo aj. parent reason why more varieties should 
occur in a jfroup having many species, than in one 
having few. 

It) test the truth of this anticipation I have arranged 
the i.laati of twelve countries, and the coleopterous 
m-Hcts of two districts, into two nearly equal masses, 
the species of the larger genera on one side, and those 
of the smaller genera on the otlier side, and it baa 
nivanahly proved to be the case tlial a larger pro- 
pnrtiv>n of tiie species on the side of the larger genera 
i-r.-seut varieties, than on the side of the smaller 
g.M,era. Moreover, the species of the largo genera 
winch present any varieties, invariably present a larger 
aver.-i^-e number of varieties than do the species of the 
«inuil genera. Hoth these re.«ult-s follow when another 
divis-on 18 made, and when all the smallest genera, 
«rith tr,^m only one to four species, are absolutely 
deluded from the tables. These facts are of plain 
Firnilicalion on the view that species are only strongly- 
mf»rked and permanent varieties ; for wherever many 
Bf." cjus of the sanie genus have been ! )rmed, or where, 
1' ^H may use the expression, the manufactory of 
«,>".:ie8 has been actire, we ought generally to find 








th«> niamit.u'tory -lill in Jictioti, mnro osppciilh V" "f" 
iiave«n(>rv rt';»Miri to iu-lii'vo llir [iri»''(ws of miiii'iractur 
intr now fpt'i'ios to be a slow ono. Ami this cert.urily 
is 'liccase. if \;»ri(>ti(>B ho looktMl at x*! incipient -.[lO.ieH; 
for my Uih'os rhNirly show as a troru'ral riih» thaf, 
wlitTpviT niariv species of a i^orius have heen forineil. 
ih'i sj)t'(ii>s of iliit jjenns pre-iont a ninnher of varieties, 
that is of ineijiii'iit species heyoiid thrt averairo. It i'^ 
not tliat all larire >>^eniTa are now varviii^' niucli, and 
are thus increa«iiiir m the numher of their species, or 
that no sTnall i,'eiiera are now varyinsf and increa«iiuf ; 
fo»- if this }iad liecii so, it woiiM Iiave hec fatal to my 
theory; inisTiiiich as ijeohiyy plainly tolls js that stnal 
irenora have in tlu! la[»so of time often increaseil tfroatly 
in size ; ami that lar:;o yenora have often come to tht>lr 
ni i\ini;», (hvlined, ami dis.ijipearod. All tliat we want 
l<> sliow is, that where many specioM of a cenus have 
been formed, on an aver;if;o many are still formiiiy ; 
and this holds ^ood. 

There are other relations between the species of 
lart!:o tfcnora and their recorded varieties which deserve 
notice. We have seen tliat there is no infallible 
criterion by which to distintjuish ispeciea and well- 
marked varieties ; and in those cases in which inter- 
niodiate links h.ive not been found between doubtful 
forms, naturalists are compelled to come to a deter- 
mination by the amount of difference between the-n. 
judjj:iiitr by analotry whether or not the amount suffices 
to raise one or both to the rank of species. Hence 
the amount of difference is one very important criterion 
in settlinti: whether two forms should be ranked as 
species or varieties. Vow Fries has remarked in retrard 
to plants, and VV'&stwood in reirard to insects, that iu 
larije jfenera Uie amount of ditference between the 
species is often exceedinjrly small. I have endeavoured 
to test this numerically by averages, and, as far as my 
impertect results ffo,. they confirm the view. 1 have also 
consulted some sag^acious and experienced r)bserver8, 
*nd, after deliberation, they concur in thi^ view. In 
tJiis respei't, therefore, the species of the larger genera 




r»'»-»'itiitiL varietich, more than do the -jK-cit's ot the 
Ktn;.lU'r jfoiii-ra. Or the case may l.t- imt m aiiotlit-r 
v;iy, and it may bo said, that in' tin- larLMT ^.-ciutu, 
.ti "Inch a numlier of varifiii's or incipient ■.pci-ies 
t'Toatcr than the avera«fe are now man n tact urinu, many 
ot the K[i<'(i»*s already manufactured .still to a i-ertjiin 
e\trnt re.-eml.le varieties, for they dirij-i from each 
other by a less than usual amount of ditference. 

.M(»reover, the s|«'cies of the larjre f^ei . ra are related 
to caih other, in the same maimer as the varieties ol 
any one species are related to each other. No natur- 
alist pretends that all the species of a t:enus aree«|ually 
duitinct from each other; they may generally he divided 
nitt) sub-cenera, or sections, or le.sser croups. A> Fries 
irds well remarked, little groups o* s{>ecies are generally 
clustered like satellites around certain other sptcies'. 
And what ?.re varieties but groups of forms, uneijually 
related to each other, and clustered round certain 
forms— that ia, round their parent->pe( ies.' I'lidoubt- 
":!y there is one most important point ot dirterenre 
iM'twoen varieties and species ; namel\ . that the amount 
•1." diHereuee between varieties, when compared with 
f ch other or with their parent-species, i.> much le»>s that between the species of the same trcins. But 
mien we come to discuss the princijde, as 1 call it, ot 
I) x.-rirenco of ( haracter, we shall see how tliis may be 
explained, and how the lesser diHercnce> between 
vaiieties will tend to increase into the >:reater ditier- 
ei.ces between species. 

lliere is one other jKiint which seems to kih worth 
.lotice. \'arietiesf{enerally have much re-tricted ranges: 
;':i statement is indeed scarcely more than a truism, 
' ir if a variety were found to have a wider rany^e than 
tiiat of it« supposed parent-species, their denominations 
i'.irhl to be reversed. Hut there is also reason to l..-lieve, 
tiiat tluMje species which are very closel\ ailie«l to 
oiher species, and in so far re^enil.le varieties, often 
'"uch restricted nni'^es. hor instance ." 


.it.M)n has marked for me in the well si i ted l^.ndou 

(.HU.U.rue of plants (4th edition) tjy j.lauti which 




thcn.i.i ranke<l as s,.o.-ie«, but which »'«;-""-'ff,'^ "^ ;! 

t),0M, r, , roputoa ^l.- i- ra.uM' on an averatfe over ■ j 
of th« ,.ro!-ince« into whuh Mr. U atson »'- J'-; •;* 
( HriUiii. Now, in thw name cat.h.r-ie,...Uckuow- 
le.luMMl varmDi;^ aro ro.or.l.Ml, an.l th..>o rantre over ^ 7 
province. ; wh.rea.. the npcMen to whuh the-^e varw.t.e- 
UloMu' ranir.' ove- lAll provinre.. N. that the a. know- 
. .M-ri vari.t.os have v.ry nc.rly t h. -'"^Z^;^.^';^"* 
AV..raco ranirn, as have those very ch.M'ly alhe<l tormn, 
markid for mo hy Mr. NN'ati^on aM .louhUol sn.-ru'S but 
who h areal-uostutmersally ranked by UriUnl. l»otan.-t* 
a;* tfo(Ml aiitl true ni)Oc;eH. 

Finally, then, have the Ham" general 
..hara.U.'rH as species, for they cat.not be <i,stn.Ru,.lu.d 
fr.n> .,....ies,--exco,.t, fir.dy, by Uie discovery of 
„t^.rm',iiate link.n^ forms, and the occurrence of 
s.,.h liak"- cannot atfiH-t ihf actual characters of the 
form-* vvlmh they connect; and except, ^ec<mdly. by a 
cJZm amount of ditference, for two torms. tl dn ennK 
vt^little. are jfenerallv ranke.1 as vanel.e., no w.lh- 
sSindin^' that intennod.ate linki.iK ^^^ms have not been 
disc e^^^ ; but the amount of ditference considered 
ueces^rv t^ pve to two forms the rank of ^pecen « 
quite maehnite. In genera havn,», r°''th«'tnecieS 
iverace number of si>ecie8 in any country, the b >e» les 
of ti^se genera have mor-. than the average numW of 
varieties In h.rge genera the «pecies are apt t« be 
closely, hut unoMually allied together, forming l.Ue 
c u.u-r roun<i species. Sneces very clos«ly 
a u-d to otlior specie, apnarentiy have restncted 
ranges In all thU several resi»ecta the of 
Hr-e L'euera present a strong analogy w^Ui varieties. 
And we c^n clearly under^Und the.e ^f »«^««'. |' 
species have once existed as varieties, and ij-je ^nus 
o^tginated: v^h.-roas, these -alopes are^utUrly m- 
explicable if each bpecien aas ucua i.i-it ;■ 

" We\ave, also, seen that it ifl the most tloun^hing 

rmj^'m^ ^itfrr:^;;^^- 



or < 

;lomin;»nt npv. irn of tlie l.iru'or tfiMU-ni ..n an 

ist ; aiiM varieti«'S, .-w wo 

lull )'lT 

iTor.uf" varv hp... , i , . . 

^(H> tend to *»'c».in»^ .niiv.Ttnl mtn now hikI di-tiri.t 
,tMM uw. Hie lftrir«T ir.'ti.'ra thus ttMi.l to Iktoiu^ l.iri:«'r; 
and throutrhowt ii.iturp th« forms of lif« .*ln.h .iro imw 
(Inniiiiaiit tiMid to li.M.mi.' 'ill moro «lumiii;iiit !•> l.-;»Mn< 
mativ mo<lin.>.l .iii'i tlorninniit ar-^riMi.l.ints. But l-y 
uteps lieroartrr to ».« pxplninf*!, tho lar-rr jfftHT.i JiNo 
Iru.l tx. hr.'.ik -ip into -m:»ll«T ir.Tieni. AikI thus, the 
fonriH of lif*? thro. it'hniit the universe l>oconic (lnJ<le.l 
into trroupH Huborditiato t« jfroups. 






Bears on natural sekcliun — Tlie term used In a wide seiine — 
Ceoinetrual fMnvcis uf increase — llapid irurease of naturalised 
iiiiiniiils and iilaiits— Nature o( the checks to Increase— ('(im- 
lieliti m univctHal — Klfecta of climate — I'rotoetlon from the 
numlier <>f iiidividuaU— (Jornplex relatiuns of all animals and 
lilaiils tliroUKliout nature — Struggle for life most severe between 
individuals and varii'ties of the same species ; often severe 
between species of the same genua— The relation of organism 
to organism the most important of all relations. 

Hkkoue enterine;' on the subject of this cliapter, 1 must 
make a few preliminary remarks, to sliow how the 
strufT^'le for existonre bears on Natural Selection. It 
has been seen in the last chapter that among-st orjrauic 
beiiiffs in a state of nature there is some individual vari- 
ability : indeed 1 am not aware that this has ever been 
disj)uted. It is immaterial for us whether a multitude 
of doubtful forms be called species or sub-species or 
varieties ; what rank, for instance, the two or three 
hundred doubtful forms of British plants are entitled 
to hold, if the existence of any well-marked varieties 
Imj admitted. Hut the mere existence of individual 
varialiility and of some few well-marked varieties, 
thou^^h necessary as the foundation for the work, helps 
us but little in understandinjf how species arise iu 
nature. How have all those exquisite adaptations of 
one part of the orj^'-anisation to another part, and to the 
conditions of life, and of one distinct ortr, .ic beinj."" tn 
another bein^, been perfected ? We see tliese beauti- 
ful co-adaptatious most plainly la tlie woodpecker and 




IUl^tletoe ; and only a little less plainly in the humblest 
parasite which ('lin«rs to the hairs of a (juadriiped or 
i'tittliers of a hinl ; in the structure of the l>eetlo which 
rl.ves tliroutjh the water; in the plumed seed which is 
wafted by the gentlest I)reeze ; in short, we see beauti- 
ful adapUitions everywliere and iu every part of the 
urtfanic world. 

A^ain, it may he asked, how is it that varieties, which 
1 have called incipient species, become ultimately con- 
verted into fTood and distinct specie.s, which in most 
<ii>es obviously differ from each other far more thau do 
the varieties of the same species ? How do those jrroups 
of species, which constitute what are called distinct 
genera, and which differ from each other more than do 
ilie species of the same genus, arise f All these results, 
ii> we shall more fully see in the next chapter, follow 
Hum the strugjrle for life. Owinjf to this strug^^fle for 
life, any variation, however slight, and fr"^m whatever 
cause pro( 'eding, if it be in any degree pi lable to an 
iiidividual of any species, iu ita intinitely complex rela- 
uons to other organic beings and to external naturt.^ 
will tend to the preservation of that individual, and 
will generally be inherited by its offspring. 'Hie off- 
sj)riug, also, will thus have a better chance of surviving, 
for, of the many individuals of any species which are 
jd'riodically born, but a small number can survive, 
i have called this principle, by which each slight vari- 
ation, if useful, is preserved, by the term of Natural 
^election, in order to mark its relation to man's power 
'>t selection. ^V'e have seen that man by selection can 
lerlaiuly produce great results, and can adapt organic 
beings to his own uses, throutrh the accumulation of 
blight but useful variations, given to him by tiie hand of 
Nature. But Natural Selection, as we sliall hc;;pafter 
see, is a power incessantly ready for action, and is afi 
immeasurably superior to man's feeble efforts, a^ the 
works of Nature are to those of Art. 

Wv will now discuss iu a litUe more detail the stru-rKif 
for existence. In my future work this subject shall Ixj 
treated, ".*? it well deserve*, at much greater length. 






Vhp plder il<^ randollf* and I. veil have lartrely and j.hi! >- 
Hoi>lji':ally -liown tl„it al! lirL'-anic beiiiL^s an? p\p(>--d 
to -^.'Vfro'.oiiii.etitioii. In rcirard to planb*, no one l-as 
tn'.-ilo.l this suhjfct with more wpirit and ahility thnn 
W. Horl>or% Do.inof \!aiirh<>-t.T. evi.!.",-tlv the n'-ult 
of his ;.-Te.-it horticultural knowlodL'-e. Nothintr i;* easier 
than to .\ilinit in words tlic trutli of the universal 
.^tru^'l;lo for li fo, or more dilficult— at least 1 have found 
it HO— than ron-tantly to hear this conclusion iu mind. 
Yet unless it lie thorou^Mily entrrained in the mind, I 
am corivuiced that the whfdo ec(uioniy of nature, with 
every fact on distrihution, rarity, ahundance, extinction, 
and variation, will he dimly seen or quit* misundersUM'*. 
We hehold tlio face of nature bright with >;ladnesM, we 
ot\en see superaliundance of food ; we do not see, or we 
forsret tliat tlie hirds which are idly sintrinj,' round U8 
mostly live on insectj* or see<l«. and are thus constantly 
dehtroyintr life ; nr we forget how largely these sont!>.ters, 
or tlieir een-i. or their nestliniT?, are destroyeil hy hirds 
and beasts of prev ; we do not always l>ear iu nnnd, 
tiuit thougli food may he now superabundant, it is not 
so at all seasons of each recurring ye^r. 

I should piimise that I use the term Strutrgle for 
Existeiicft in a large and metaphorical sense, iuciudhii; 
dependence of one being on another, and includins; 
(which is more important) not only the life of the uiui- 
vidual, but success in leaving progeny. Two canine 
animals in a time of dwirth, may be truly said to 
stru:rgle with each other which shall get food and live. 
But a plant on the edt^e of a desert ia said to struggle 
for life against the drought, though more properly it 
should be said to be dependent on the moisture. A wliieli annually produces a thousand seeds, of 
which on an average onlv one comes to maturity, may 
be more truly said to struggle with the plant^s of the 
same and other kinds which already clothe the groun(L 
Ibe mistletoe is dependent on the apple and a few other 
trees, hut can only in a far-tetched sense be said *o 
Btru^ri^le with these trees, for if too many of those par*- 
Bites tfrow on the same tree, it will languish and di* 



But 9« sce-llini.' mistletoe?, trrowiri;: close toirether 
on Mie win\« braiicli, may more trtily be said to ntrue<r!« 
with ricli other. As th« mistletoe is diss^emiiiateii i>y 
bin!-', iU existenre do[>en<l9 on birds ; and it may met*- 
pl'orically be said to titriiuijlp with other fruit-bearintf 
planta, in order to tempt binis to devour and thus 
disseminate itg seeds rather than those of other j)l.'\utM. 
In these several sensfs, which pass into eacli other, I 
a»o for convenience' sake the general term of strujjgle 
for existence. 

A strutrtjle for existence inevitably follows from the 
hii^h rate at which all ortranic beinjjs tend to increase. 
Every beinj^, which during its natural lifetime produces 
several eggs or seeds, must sutFer destruction during 
some period of its life, and during scmie season or occa- 
sional year, otherwise, ou the principle of geometrical 
increase, its numbers would quickly become bo in- 
ordinately great that no country could support the 
product Hence, as more individuals are produced 
than can possibly survive, there must in every case 
be a strugjf le for existence, either one individual with 
another cf the same species, or with the individuals of 
distinct species, or with the pby^ cal conditions of life. 
It is the doctrine of Malthus' applied with manifold 
force to the whole animal and vegetable kingdoms; for 
in this case there can be no artiticial increase of food, 
and no prudential restraint from marriage. Although 
some species may be now increasing, more or less 
rapidly, in numbers, all cannot do so, for the world 
would not hold them. 

There is no exception to the rule that every organic 
being naturally increases at so high a rate, that if not 
destroyed, the earth would soon be covered by the 
progenv of a single pair. Even slow-breeding man has 
doui)led in twenty-five years, and at this rate, in a few 
thousand years, there would literally not be standing 
room for his progeny. Linnieus h<i« calculated that if 
an annual plant produced only Iwu nee*!.'*^ — aiid mere ia 
no plant so unproductive as this—and their seedlings 
next year produced two, and so on, then in twenty 




jt^ira there would 1)6 a million plants, Tlie elephant it 
re< koiied the slowest breeder of all known animals, 
and 1 have taken 8<ime ]iainH to e»>tiniate itu proliahle 
mitiitiiam rate of natural increase: it will be under the 
mark to assume that it breeds when thirty years old, 
and poes on breeding till ninety years old, brinffiixg 
forth three pair of youuf^ in this interval ; i; this be 8o, 
at tiie »Mid of the fifth century there would be alivf 
dfteen million elephants, descended from the first pair, 
liut we have better evidence on this subject than 
mere theoretical calculations, namely, the numerous 
recorded cases of the astonish inj^ly ra}iid increase of 
various animals in a state of nature, when circumstances 
have been favourable to them during two or three 
following seasons. Still more striking is the evidence 
from our domestic animals of many kinds which have 
run wild in several parts of the world : if the Ktatemeutg 
of the rate of increase of slow-breeding cattle and 
horses in South America, and latterly in Australia, had 
not been well authenticated, they would have been 
incredible. So it is with j)lanta : could be given 
of introduced plants which have become common 
throughout whole islands in a period of less than ten 
years, 'several of the plants^ such as the cardoon and 
a tall thistle^ now most numerous over the wide plaiuf 
of I.a Plata, clothing square leagues of surface almost 
to the exclusion of all other pl-'>.ut8, have been lutro- 
duced from Europe ; and there are plant* which now 
range in India, as I hear from Dr. Falconer, from Cape 
(.'omorin to the Himalaya, which have been imported 
frt in America since its discovery. In such cases, and 
fudless instances could be given, no one supposes tL<\t 
the fertility of these animals or plants has been suddenly 
and temporarily increased in any sensible degree. 'ITie 
obvious explanation is that the conditiont< of life have 
been very favourable, and that there has consequently 
been less destruction of the old and young, and that 
nearly all the young have l>een enabled to breed. In 
such cases the geometrical ratio of increase, the 
result of which nevCi faih> t<. he surprising, simply 



CAplnins tn4> ftxtnonlinarily rapid iiu-rease and wide 
'H-fijtinnof iiatur:ili-ed nroductioiis in their new homes. 
In a «tate of nature almost every plant prodnces seed, 
and amoinrst anitnals there are very few which do not 
irinually pair. Ilfnce we may oonfidently xssert, that 
nil plants and animals are toridiiitr to increase at a 
ireometrica! ratio, that all would most rapidly -ititck 
every station in wliicli they conld anyhow exist, and 
that the ;,'enmetrical tendency to must he 
•he(!ked by destruction at some period of life. Our 
familiarity with the larer» domestic animals tends, 
I think, to mislead us : ^ see no great destruction 
fallin^r on them, and we forj^et tliat thousands are 
annually slautflitered for food, and that in a state of 
nature an equal num')er would have somehow to l»e 
disposed of. 

'Hie only difference between "•;;anisms which annually 
produce egj^s or seeds by the thousand, and those which 
produce extremely t'evr, is, that the slow-hree<lers would 
require a few more years to people, under favourable 
conditions, a whole, district, .et it be ever so lartre. 
Die condor lays a couple of ej^gs and the ostrich a score, 
and yet in the same country the condor may be the 
more numerou.s of the two : the Fulmar petrel lays 
but one e^g, yet it is believe<i to be the most numerous 
bird in the world. ( )ne fly deposits hundreds of e^^s, 
and another, like the hippohosca, a sin^'le one ; but 
this difference does not determine how many indi- 
viduals of the two species can be supported in a district 
A large number of ecp* ia of some imjtortance to those 
species which depeofi on a rapidly fluctuating' amount 
of food, for it aUowg them rapidly to in 
number. But the real importance of a large number 
of eggs or seeds is to make up for njuch destruction 
ftt some period of life ; and this period in the great 
majority of ca.so8 is an early one. If an animal can in 
any way protect its own eggs or younL'.a small number 
may be produced, and yet the average stock be fully 
kept !!p; but if many eggs or young are dewtroyed, manj 
must ie produced, or the flpeciew will become extinrt. 

t ' 




It would «ufTice to keoj» up the full numher of a tree^ 
wliich livt'il oil nil avi-ruiso for a tliOii>uiid years, if a 
fciii^le (jfetl wore proiiiiced once iii a thous-iud years, 
»u]'j><)sintj; that tUi^ seed were never destroyed, rind 
could he ensured to {germinate in a hltin^' place. 
So tliat in ail tasi'>, the averat^e numher of any animal 
or plant depends »)nly indirectly ou the nundier of it*: 
egp? or seeds. 

In looking' at Nature, it is most necessary to keep 
the foretioinfr considerations alwavH in mind - never to 
foiiiet that every single orjranic heinj; around ufl may 
l»e said to he Htrivinj? to the utmost to increase in 
numbers ; that each lives hy a 8trugt(le at some period 
of its life : that heavy dotruclion inevitahly falls 
either on the young or old, durin><: each ^feneration 
or at recurrent intervals. Liirhtcu any che<'k, militate 
the destruction ever so little, and the nun»her of the 
species will almost instantaneously increase to any 

'Ilie causes which check the natural tendency of each 
epecies to increase in uund>er are most ohscure. Look 
at the most vigorous sjiecies ; hy as mucli as it swarms 
in uumhers, hy so much will its tendency to increase 
lie still further incr«^ased. We know not exactly what 
the checks are in even one sin^rle instance. Nor will 
this any one who reilecLs how if^-norant we are 
on this liead, even in rejjard to mankind, so incompar- 
aMy hetter known than any other animal. Iliis .suhject 
has been ahly treated hy several authors, and I shall, 
in my future work, discuss some of the checks at con- 
Siderahle len^h, more especially in regard to tlie feral 
animals of JSouth America. Here I will make only a 
few remarks, just to recall to the readers mind some 
of the chief points. Ktrj^ or very young animals seem 
g-enerally to suffer most, hut this is not invariahly the 
case. U'ith plants there is a vast debtructiou of seeds, 
hut, from some observations which I have made, I 
bt'iieTe ilitti il is tht; seenirm^s wlncli Suiief most frotn 
^ermioatinK in ground already thickl; slocked with 
other plants ^^eAdiings, also, ar« destroyed in vatit 



nuinhers by various enemies ; for instance, on a piece 
of frround three feet lon^ and tno wiiic, dutf and 
rleari'<i,and where there could he no cliokin:: fjom 
(•iher plants, 1 marked all the sccdlintrs of our ri.ilive 
weeds as they cmiie uj>, and out of the .N/iT no hv-s llian 
2.t6 were destroyed, chiefly by filugs and insei t.'.. If 
turf which lias long^ heen mown, and the case \foiild he 
'he same with turf closely hrowsed by ([iiidrujteds, he 
h t lo (Trow, the more vigorous plants trradu.illy kill the 
les> vitrorous, thoujrh fully trrown. plants: thus out of 
twenty species ffrowint' on a little jilot of turt (three 
teet by four; nine species perislied from the other sjtecier 
heiiiii" allow e<l to ^row up free! v. 

1 he amount of food for each species of course trivee 
the extreme limit to whidi each can increase ; l»ut very 
frO(juent]y it is not the obtaining food, but the scrvinj; 
as j.rey to other animals, wiiirh determines the averajjc 
nuniiiers of a species. Tlius, there seems to Ik little 
doubt that the stock of partridtres, grouse, and hares on 
ruiy larj^^e estate depends chiedy on the destruction of 
vermin. If not one head of gume were shot during 
the next twenty years iu Kngland, and, at the same 
time, if no vernnn were destroyed, there would, in all 
firobability, be less game than at pre>ent, altluuigh 
hundreds of thousands of ^ame animals a;c now 
iiiiiiually killed. On the other hand, in some cases, 
:is with the elephant and rhinoceros, none are destroyed 
by beasts of prey : even the tiger in India most rarely 
dares to attack a young elephant protected by its dam. 

(Jlimate plays an important pan m determining tiie 
average numbers of a species, and {teriodic^l seasons 
1 r extreme cold or drought, I believe to l)e the most 
I fi-ctive of all checks. I estimated that the winter of 
1 ;.'>4-5.5 destroyed four-fifths of the birds in my own 
jiouuds; and this ie a tremendous destruction, when 
He rememl>er that ten per cent is an extraordinarily 
H-.ere mortality from epidemics with man. The action 
'I Climate seems at first sight to be quite independent 
'•: the struggle for existence ; but in so far as climate 
c,'i:ody act« in reducing food, it briujfrs on the most 



neverft struff^rle hotwwn tho individuals, whother ot 
the same or of di-;tiiirt species, v^ liioli sui>sist on th»« 
same kiml of food. Kvi>ii when ilim.ite, for instance 
extreme .-old, art^ directly, it will l-e the least vijforom, 
OP Ihdso v-hiih have jrot least foo<l throui^h the advanc- 
in:r winter, which will -uifer most, ^^■hen we travel from 
south to riortii, or from a damp rejrion to a dry, wm 
invariahlv see some species ^'radually :i:ettin^ rarer aid 
rnrer, ard tiiially di<apj»earintr *, ii'id tho chanjro <>i 
climate hein:: conspicuous, we are tempte<l to attritni'e 
the whole etlot to its direct action. Hut this is a 
false view : wo forjfet that each species, even where it 
most ahoiiniK, is constantly sutferin;; enormous de- 
struction at some period of its life, from enemies or 
from cd'iipetitors tor the same place and food ; and if 
tlie^e enemies or competitors ho in tho least de^ee 
favoured hy anv alif^ht change of climate, they will 
iiicreape in inim'hers, and, as each area is already fully 
stocked with inhahitants, the other species will 
When we travel southward and see a species decreas- 
iuj in numhers, we may feel sure that tlie cause lies 
quite as much in other' species heinjj favoured, as iu 
this one beiuir luirt So it is when we travel northward, 
but in a somewhat lesser de^jree. for the number of 
species •►f all kinds, and therefore of competitors, 
(lecre.ises northwards; hence in ^^oinff northwanl, or 
in a,scend:n^: a mountain, we far oftener meet witli 
•stunted forms, duo to the directly injurious action of 
climate, than we do in proceedinff southwards or iu 
descending? a mountain. When we reach the Arctic 
regions, or snow-capped summits, or absolute desert-", 
the strufTijle for life is almost exclusively with the 

That climate acts in main part indirectly by favour- 
iutr other species, we may <'learly see in the prodi^ou<» 
numljer of plants iu our {gardens which can perfectly 
well endure our climate, but which never becon-e 
naturalised, for they cannot cf • pete with our native 
plants nor resist destruction by our native animals. 

When a species, owiiitf to hitrhly favourable circum- 



•-tances, increase!* inordinately in nunihors in a small 
•.ra«;t, epidemics — at least, tins seems jrenerally to occur 
with our jraiiio animals — often ensue : and liere we 
have a liniitiiitf clierk independent of the slrujfjfle 
!ur life. Hut even some of these so-railed epidemics 
a]>pear to he due to parasitic worms, wfiich liavo from 
<otne cause, pos»ildy in part throutrh facility of diffusion 
amongst the crowded animals, l»een disprojiortionahly 
favourec! : and here comes in a sort of Htrujftrle hetweeu 
the parasite arul its l>rey. 

On the (tther hand, in many cases, a lar^o stock of 
individuals of the same species, relatively to the num- 
bers of its enemies, is ahsolutely necessary for its pre- 
■<ervati<in. Fhus wo can easily raise plenty of corn and 
rape-seed, etc., in our fields, i)ecause the seeds are in 
trreat e.xcess conipare<l with the numher of birds which 
teed on them ; nor can the birds, though having a 
superahuiwlance of food at this one season, increase in 
numher proportionally to the supply of seed, as their 
numbers are checked during winter: hut any one who 
has tried, knows how troublesome it is to jjet seed 
from a few wheat or other such plants in a jjarden : I 
have in this case lost every single seed. Tliis view of 
the necessity of a lartre stock of the same species for 
its preservation, explains, 1 believe, some sinj^ular facts 
in nature, such as that of very rare plants heinjf some- 
times extremely abundant iu the few spots where they 
do occur ; and that of some social plants beiiiff social, 
that is, abounding in individuals, even on the extreme 
confines of their range. For in such cases, we may 
believe, that a plant could exist only where the con- 
ditions of its life were so favourable that many could 
exist together, and thus save the species from utter 
destruction. 1 sliould add that the go<Ml eltects of 
frequent intercrossing, and the ill etfects ot close inter- 
breeding, j»rob;ibly come into play in some of these cases; 
t)ut on this intricate sulijed I will not here enlartre. 

."•iiiiiv ca-cs are on ieo«mi ?iuiv»iii4{ in.w Cdiripiex ana 
unexpecteii are the checks a;id relations between organic 
l>eiugs which have to struggle together in the same 



country. 1 will pive only a sluffle instance, which, 
thou^rh a Himple ^ue, has interesteil me. In StatforC- 
rthirt', on the eNtiile of a relation, where I had ample 
itifans of iiive><titratioii, there w;is a lar^e and extremely 
l.arren heatli, which had never l»cen tom-hed by the 
hand of man ; hut several liundred acres of exactly 
the same n.itiire had heen enclosed twenty-five yearn 
previously and planted with Sc.tcli fir. Ihe change in 
the native ve>feUtion of tlie planted i>art of the heath 
was remarkable, more than is Kcuerally seen in 
passing from one quite ditferent soil to another : not 
only the proportional numbers of the h< ith-plants were 
wholly chan^red, but twelve species of plants (not 
countintf jfra.sses and carices) tlourished in the planta- 
tionH, wliich could not \>e found on the heath. The 
etfect on the insects must have Uvn still jrreater, for 
six insectivon)us birds were very common in the planta- 
tions, which were not to be seen on the heath ; and 
the heath was fre<iuented by two or three distinct 
insectivorous birds. Hero we see how potent has been 
the etfect of the intrttduction of a sintrle tree, nothing 
whatever else having been dune, with the exception 
that the land had been enclosed, .so that cattle could 
not enter. Hut how important an element enclo e 
is, I plainly sjiw near Karnliam, in Surrey. Here there 
are extensive lieatlis, with a few clumps of old Scotch 
tirs on the dist^mt hill-tops : within the la.«t ten years 
lartre spaces have been enclosed, and self-sown lirs are 
now sprin^jiuiT up in multitudes, .so close to^rether tliat 
all caiuiot live. When 1 ascertained that these youujf 
trees had not been sown or planted, I was so much 
surprised at their nuribers that I went to several points 
of view, whence I coubl examine hundreds of acres of 
the unencbised heath, and literally 1 could not see a 
sinjfle Scotch fir, except the old planted clumps. But 
on lookiiiij closely between the stems of the heath, 
I found a multitude of seedlings and little trees, which 
had been perpetually brtmsed down by tnc cattiC. Ic 
one square yard, at a point some hundred yards disUnt 
from one of the old clumps, I counted thirty-two little 




Uer.i ; and otip of them, with riiiir« oJ 
trrowth, had duriijtf many years tried to raise its head 
above the stems of th»' ht-ath, ami ha«l failtHl. N'o 
wonder that, as soon a- the land was enclose*!, it l>«- 
' ame thickly clothed with vijforously^rrowiiifi^ youii^r fifH. 
Vet the heath was so extremely harreii and so extensive 
that no one would ever liave iniatrined that cattle would 
hive so closely and etfectnally s«'arched it ror food. 

Here we see that cattle absolutely determine the 
existence of the ^>cotch fir; hut in several narbt of 
the world insects determine the existence of cattle, 
i'erhaps Paraguay otfers the most curious insta' 'e of 
this ; for here neither cattle nor horses nctr dt.^-s have 
ever run wild, thouj^h they swarm southward and 
northward iu a feral state ; and Azara an<l Hentrirer 
Kave showu that this is caused hy the t: reitter numher 
111 Paraguay of a certain Hy, which lays its » /jfs in the 
navels of these animal?, when first Imru. 'Ihtj increase 
of these dies, numerous as they are, mus^ ue naliitually 
ihecked by some means, probably by birds. Hence, 
if ( ertiiui insectivorous birds (whose numbers are f>rob- 
ably regulated by hawks or beasts of prey) were to 
increase in Paraguay, the flies would decrease — then 
cattle and horses would become feral, and this would 
(ertainly greatly alter (as indeed I have observed in 
parts of bouth America) the vegetation : this again 
would largely affect the insects ; and this, as we just 
have -ieen iu Staffordshire, the insectivorous birds, and 
>o onwards in ever-increasiruf circles of complexity. 
\\ e l)egan this series by insectivorous birds, and we 
have ended with them. ' Not that in nature the rela- 
tions can ever be as simple as this, liattle within 
iialtle must ever be recurring with varying success ; 
and yet in the lontr-ruii the forces are so nicely 
balanced, that the face of nature remains uniform for 
lung periods of time, though assuredly the merest trifle 
would oflen give the victory to one organic being over 
aiiutiier. Nevertheiess so profound is our ignorance, 
and so high our presunijjtion, that we marvel when we 
iioar of the extinction of an organic being ; and as we do 



i t 

n<»t -♦'« llie o.m-i-. \v«' invoke caUclysnis to ciesdlate the 
w«)rlil, or iiiMMit l.iwn on tlu- diinilioii of tlic forms of life I 
I Hill t»'nii>t»Ml U) ixxw one iiioro iiistaiuw kIiowiiut how 
phiiits ami Hiiiiiiain, nio.-^l rfinoto in th<> scalw of nature, 
are hoiiiul tou'i'ther V)y a weh of coinj.lfx relations. 1 
shall li.T.MMfr have o<-<M-ion to show that the «xotic 
l/.l.«'lia nile-'-ii^, in th -. i.;ii t of KM^'lall<^, is tuner visited 
hy insert-, and conseftueiitly, from its pe.iiliar strnrtiire, 
Mfv.r can set a seed. .Many of our orrhuhKeons plants 
al.M.liitelv r.'.|iiir.' tlui visits of mothn to remove their 
i,olleii-ma»es and thus to fertilise tliem. 1 have, also, 
reason to I.elieve that hiimhle-hees are indi-|'ens.khle to 
tlie ferlili-.ition of the he.irtsea>e i<da tricolor), for 
other hee-. do not visit tins riower. From experimeiits 
whi.-h 1 have lately tried. 1 have found that the visits 
of hees are necessary for the ferlilisati(»n of some kinds 
of clover ; hut hunihle-hees alone visit the red clover 
(Triftdium pratense), as other hees cainiot reach the 
nectar. Hence I have very little douht, that if the 
whole trenus of huml)le-l>ees Itecame extinct or very 
rare in Kntrland, the heartsease ami red clover would 
become very rare, or wholly «li«ippear. The number 
of humhle-'hees in any district dei»end9 in a jrreat 
de:rree on the number of tield-mice, which destroy 
their comhs and nests; and Mr. H. Newman, who ha» 
lonjf atteiKled to the habits of humble-bees, Wlieves 
that ' more than two-thirds of them are thus destroyed 
all over Kn;:land.' Now the numl»er of mice is larjfely 
d<'i>endent, as every one knows, on the numl)er of cats ; 
and .Mr. .Newman iays, ' Near vilhitfes and small towus 
1 have found the nests of humble-bees more numerous 
than elsewhere, which I attribute to the numl>er of 
cats that destroy the mice.' Hence it is (juite credible 
that the presem'-o of a feline animal in lartre numbers 
in a district mijrht determine, throuirh the intervention 
first of mice and then of bees, the fre.iiiency of certain 
flowers in that district ! ^ i --i - 

In the case of every species, iii.tny dirforent ciiCcks, 
actinir at different periods of life, and durinjr different 
Hea»^aus or years, probably come into play ; Bt)me one 



iifi k or Home few \>**:uu uvuemlly 'lie irio-t p.itrnt, 
Imt all nmrur iii <lt't»'rmiMinif the avrraire inirMlxT or 
even the ••xi^'teiirc of tlie sj,«Mij«<4 |ti some ra-e** it Im sliowii tli;»t » idelv-dirT'Tctit .•lie>'ks art on llie 
-ame Hpecie-* in i!itfi>reiit distri"^*. V\ liffi we look at 
liif plants ami lni!*lie>« clMtlinii.' an entanirlfl t>,-ink, we 
are tempted to attrilmte their proportional miniU»r«* and 
Kinds to what we call chaiue. Kiit how fal-e a view 
- Mils I Kverv one ha-i heard that when an American 
torent \h cut down, a very differeTit veiretation »'pnnf^ 
lip ; hut it has hven oiiierved that ain ent Iiuiian ruin* 
;n the Southern I nited Stages, which niiint formerly 
have heen cleared of trees, now di^Jjdav the -.ame 
lieautiful diversity and proportion of kirn'- as in the 
>urroundintr virL'ni fore>;ts. V\ liat a «truu„'le U'tween 
tlie several kinds of tre«'s must here have jrono on 
liiirintf loritr eenluries, eadi annually scatteriinf iti 
s»'cds hv tiie thousand ; what war hetween ni«-ect and 
mseet — hetween insects, snails, and other animals with 
l)ir>la and beasts of prey-all strivintr to increase, and 
all feeding on each other or on the tree- or their seeds 
and «eedlinirs, or on the other plants whi'K first clothed 
the irround and thus che<-ked the trrnwth «>r the trees ! 
riirow up a handtul of feathers, and all must fall to 
tli" ground accordinjf to detinite laws ; hut how •simple 
i> this prohh'm compared to the a<'ti(»ri and redaction 
(if the iruuimerahie plants and animals which have 
i<''erniiued, in the cours** of centuries, the projtor- 
t.Dnal niimhers and kinds of trees now uTOwinir <>'i the 
idd Indian ruins I 

The dependency of one oriranic heintr on another, as 
of a parasite on its prey, lies trenerally heiwecn Keinp? 
■emote in the scale of nature. This is ortcn the case 
•tit}) tlio'ie wliich may strictiv he said to strutrtrl*' with 
.ifh other for existence, at* in the case of hMUSts and 
jTx-s- feeding quadrupeds. But the >Jtrut:.'le almost 
:i\ iriahlv will he mo<t .severe hetween the individuaU 

■ 1 ' .■ . ) - i- ^ - i * I — -._-.., .1 ; * _; ^A^ 

/T tiiti Same !i{iiH'i«'S. i!".rirH.'y irutjU!";; ;i:f :.a:i:;- :;;-•.; :-._l», 

re Hire the s.-irr,e food, and are expo^^ed to the same 
iaiitjers. in the case of varieties of the same specie*, 




the stnitf^le will p;enerany he almost equally severe, 
and wo snmetiTnes see the contefit soon decided : tor 
instance, if severnl varietit.-s ofwlicat he sown toffethpr, 
and the mixed seed 1>»' resown, sme of the varieties' 
whirl) lif^t suit the '■oil or climate, or are nanirally the 
tn'»-«t fertile, will heat tlie others and so yield more 
seeil. and conseiiiuMitly in a few years (juite "tipplajit 
the otlier varieties. To keep up a mixed stock of even 
such p.vtreniely close varieties as the variously coloured 
8wef't-j)eav, tiiey must he each year harvested sej)arately, 
and tlie see'l then mix«-ii in rliie proportion, otherwise 
the weaker kinds will steadily decrease in numbers 
and disappear So airain witli the varieties of sheep : 
it lias }i('«Mi as.serted that certain mouutiin- varieties 
will starve out oilier mountain-varieties, so that they 
cai.iiol l>e kept "opether. The same result has 
fnl lowed from licepinfT ditFerent varieties of the 
ni»'diriiial loc. li. It may even he doubted whether the 
varieties 4)f ativ one of our domestic plants or animals 
have so exactly the same strenarth, habits, and con- 
stitution, that the oritrinal proportions of a mixed 
stock idiiid be k( pt up for hali-a-<iozen generations, if 
they were allowed to strujr^rlo to>rether, like l)ein^'-s in a 
stite of nature, and if the seed or younj^ were not 
annually sorted. 

.•\« species >f the same ?renus have usually, though 
by no me^iiS invariably, some similarity in habits and 
con^titutioT!, and always in structure, the strufffirle will 
trenerally be more severe between sj»e(ies of the 
^ame eenus, >*hen thev come into comjtetition with 
lacli other, than iietween species of distinct genera. 
We see this in the recent extension over parts or the 
L'niteii St.'ite« of oi^e species of swallow having caused 
the decre.i.-e of Hfiot her --pecies. llie receiM increase of 
the mihsel-tiirusli in parts of ><()lland liap caused the 
decrease of the sontr-thnish. I low freji.ently we hear 
(»f cue species of rat taking- the place of another species 
uuuer iie mosl uiiierj-iu riimaieH .' in Kussia iiie 
•mall .Asiatic cockroach has evervwhere diiven t>efor»^ it 
ita jfr'^i! . ontr^ner. One speeie'j nt j^!?* 1' tuI 

•l j>- 



plant another, and so in other cases. ^\ . n dimly 
M^e whv the competition should be inost se. t*rv between 
allied 1 irms, which fill nearly the same place in tlie 
i-conomy of nature ; hut probably in no one case could 
*e precisely sav why one sjiecies has been victorious 
over another in tbe great battle of life. 

A corollary of the hijrhest importance may \>e de- 
duced from the foreiroiiiir remarks, namely, that the 
structure of every ortranic beit;.c is related, in tbe most 
e«5sential yet often hidden manner, to that of all other 
.irtranic beings, with which it comes into competition 
tor food or residence, or from which it ha.s to escape, or 
on which it preyn. l'h\< is obvious in the structure of 
the teeth and talons of the tip:er ; and in that of the 
iejrs ?.n(i idjivvs of the parasite which clinifs to the hair 
on the timer's body. But in the beautifully plumed seed 
of the dandelion, and in the flattened and frintred U"j;s 
of the water-beetle, the relation seems at first confii.ed 
to the elements of air and water. Yet the advantaije 
of plumed seeds no doubt stands in the closest re- 
lation to the land being' already thickly clothed by other 
plants ; so that the seeds may be widely distributed and 
fall on unoccupied pround. In the water-beetle, the 
structure of its letrs, «o well adapted for divinff, allows 
it to compete with other aijuatic insects, to hunt for its 
own prey, and to escape serving as prey to other animals. 

Ihe store of nutriment laid up within the seeds of 
many plants seems at lirst sight to have no sort of 
relation to other plants. But from the strong growth 
of young plants produced from such seeds (as peas 
uid beans), when sown in the midst of long grass, I 
■iu-pect that the chief use of the nutriment in the see«l is 
t" favour tho growth of the young seedlintr. w liilst strug- 
ir' with other plants growing vigorously all around. 

l>)ok at n plant in the niiiist of its range, vvhy does 
'* not douide or (luadrwple itfi numbers? W'e know 
'.;iat it can jterfectlv >oll withstand a little more li.jat 

■I V Oiu, UitiiiTiue.-v^ VII uivi"ies:>, lOT Ci.sCWncrC iv iciii^CS 

!to slifi'htlv butter or cnlder, damper or drier districts. 
li ihis case *'« <'aii clearly see *hat if we wished in 



imaLniintion to irivo tlio iilaiilllio power of iiicreasine: in 
number, we slioiild liave to ^nv»» it >nme advant.itro over 
its cdniix'titors, or over tlu' aiiinial> which preyt-d on it. 
( )m the cell 111 It's of its t^vnu-rapliical raiiire. a cliaiiire of 
constitntKiii witli respfct to ciutiat»> .Miuld cloarly he an 
a(lvant:i:ic to our phiiit : l)iit we have reason to helie.e 
that only a tew platit-or animals ranire so far. that tlsey 
are ilestroyed hy the riL-'oiir of the rliiuate ah)ne. Not 
until wo rea«'ii tlie extreme confines of life, in th« 
Arctic rcL'-ions or on the horders of an utter desert, will 
competition cease. 'Hie land may he extremely cold or 
dry, y»'t there will he competition between >.oine few 
species, or J>etween the individuals of the same species, 
for the warmest or dami)est spots. 

Hence, also, we can see that when a jdant or animal 
is placed in a new country amon^r-t new competitors, 
tliouirh the climate may he exactly the same as in 
its former home, yet the comiitions of its life will 
g-eiierally he ch;ir.(red in an essential manne-. If wo 
wi--}ied to increa- its averatre nu'nhers in its new home, 
we should have to modify it in a ditferent way to what 
we <lioii!d have done in its native country ; for we 
should have to trive it some advauta^re if. er a dirferent 
sot of com|>etilors or enemies. 

It is srood thus to try m our imajjination to irive any 
form some advantaire over another. I'roiraidy in no 
siiitrle iiiNtance should we know whai t<. do. so as to 
succeed. It will convince us of our ij^norunce on tt'e 
mutual relations of all oriranic ifiiiirs ; a .-oiiviction as 
necessarv. as it seems to he diilicult tr) aiijiiire. .Vll 
that we can do, is to keep ste.tUily in mi; d that each 
or;ranic lieintr is striviiiL-- to increase at a tri'<nnetrical 
r.itio ; that each at atune period of its life, duriiiff some 
e;>s(»n of the vear. durintr each L'i'neration or at 
intervals, to stru;:ule for life, and to surier ^reat 
destruction. \\ hen we reflect on this strutrLHe, we may 
conscde ourselves with the full belief, that the war ot 
oatuie i"« (Mil. iii, »-*"*iiijl. Tuitt iiO tCar :■' ::■;■., .;:.l; iiJ'.;:-u 
ifj treiierillv jirompt. and tliatthe vinnrous, the healthy, 
ar-d the happy survive and muitijiiy. 



N»tur»l Selection — lU power conipartil with mans nelectl 'n - Ita 
power on oharactfrs "f trifling itnii'itmcc- iu p<iwer »t all a<fw 
and on both sexes Sexual S»-lecti"ii- on Die Rfntralitj i.( lnt«r 
cr'isne* l)etwfen iiniivi'liiaU of the same six>i-ie»_i.lrcnnigtaiife« 
favourable ami unfavourable t» Natural Self tiori, naniel>, Inter- 
i;rossinK, iBolatl'Ti. number of in<livi(lual»- Slow a<lion — F.itlnc- 
tlon (ause<l bv Natural Selection— Kiverir-'iice of C'barai-t*r, 
relat«.l to the diversity of inhabltanU of any ginall area, ao>l t.-> 
uaturalisatioii Action of Natural Seleitiou, thr^ ugh liiverKence 
of Character and V.xtiiii ti'n, on the descei,clai;ts from a common 
paren^-Exp^ain8 the Grouiiing of all org-inic beluga. 

How will the strujrtrle for fxisteiK-e, discussed too 
brietly ill the last chaptor. act in rei'-:ird to variation? 

aTi the [)riiuMj)le of soleilion, which we have seen is m> 
[totent in tin; hands of man. apjdy in nature ? I think 
AP shall see that it can act most elTectually. I>et it \>e 
*iorne in muid in whit an endloss number of straii;,^e 
IM'cuitarities our dome.s'tic producLions, and, in a lc-ss<;r 
(ii-^rree, those under nature, vary ; and how t.tron^'' the 
'icreditary tendency is. I'nder donu'stication, it may 

■0 truly naid tliat the whole oriranisatiun hec dme-. m 
-ome degree j)la>tic. liOt it he horno m mind how 

nfiiiitely coniiilex and close-fitting are tlie mutual 
relations of ail ortranic heiiiys to each other .intl to 
'heir physical conditions of life. Can it, then, be 

linuirht improhable, seein^j that variations useful to 
man have undoutiiedly occurre.i, that other variationi 

'i^fiui ill non"ic "<Vi»v to irac'ii liaiiii m t-nv &•■";.%«». a.isi !,;!Ui- 

;ilex battle of lite, sl>r»uld sometimes occur in the course 
of thousands of gener;ttions } If such do <M:cur, can we 






doubt (remembeririff that many more individuals are 
bom than can possibly survive) tliat individuals havinvr 
any advaritaffe, however slig'ht, over others, would liave 
the best «;liaiice of surviving and of procreating their 
kind? On tlie otlier hand, we may feel sure that any 
variation mi the least de^ee injuriouy would l»e rigidly 
destroye<l. This {(reservation of lavourable variatioiiH 
and the rejection of injurious variations, I call Natural 
Selection. Variations neither useful nor injurious 
would not be fiffected by natural seie<-tion, and would 
l>o left a fhK'tuatinj; elenu'iit, as pcriiaj)- vve -;t'e iu the 
B)>ei-ies called jiolyinorpbic, 

\\'e shall best uiidt-rstand the probable course of 
natural selection iij takiu;: the case *it a <;ou!itry undor- 
irointr some physical chanjTc, for instance, of climate. 
Tlie proportional numliors of its inhahitantf vrould 
almost immediately umicrro a chantre, aiid some i«j)ecies 
miffht l(ec«»me extinct. ^\'c may conclude, frotn what 
we h.ive seen of the intimate and complex manner in 
wliic; the inhab Unts of each country are bound i(>- 
^ether, that any chaiiife in the numerical proportions <if 
some of the inhabitants, inrle[)endently of the chan^-^e 
of climate itself, would seriously affect many of the 
others. If the country vere oj)en on its borders, new 
forms would <'ertainly immig-rate, and this also would 
seriously disturb the relations of some of the former 
inhabiiants. Let it be remembered how powerful the 
iiiriuence of a sino^le introduced tree or mammal has 
been sliown to Ik>. But in the case of an islan.' , or of a 
country partly surrounded by b.irriers, uito which new 
and better adapted forms could not freely enter, we 
should then h.-ive places in the economy ttf niture which 
wfoild ;issure<ily be br'tcr tilled up, if some of the 
oritrin;)! iiihahitiints '.v^re iu some manner modified : 
fof-, lia(j tlie area ;)een open to immiirraiio.'i, these .>,ame 
places would liave been seized on by intruders. In such 
case, every sJiL'^ht modirication, which in the course of 
a4fes >-ijaiuo«i io ir.sH. and whicii iu any way favoured 
the individu.ils oi any of tiie species, by lietter adap-tin^ 
tht-tn to their alteretl ('••>nditiori«. would tend to be pre- 




served ; and natural selection would thus ?jave tree si ope 
for the work of improvement. 

U'e have re;i-on to believe, as stated in the first 
chapter, that a chanfre in the condition.- of lite, hy 
specially acting on the reproductive system, cause's or 
increases variability; and in the forec'np ra^e tlie 
contUtions of life are 9Up{)osed to liave uriderfrcii"- n 
change, and tliis would manifestly be favourabi. to 
natural selection, by tfiviu^r a l>etter chance of 
vari,itious occurriiifr ; and unless profiUhle variations do 
occur, natural selection can do nothinff. \ot 'hat, as J 
believe, any extreme amount of variability - necessarv ; 
as man can certainly produce ^eat resuita by add; ^ 
up in any given direction mere in''ividual ditferemes, 
so could Nature, but far more easily, rom havi iriiwom- 
i-rirauly loiiiirer time at her di^^posal Nor io 1 believe 
lliat any physical rhanii-e, as of climate, or ariv 
unusual de-r.-ee of isolation to (heck immiernttioii. i« 
acraall> riocessary to produce new and unoccupied 
plaije*^ for natural selection to til] up by modifying 
and improTHig- some of the varying inhabitants. For 
as ail the inhabitants of each country are struir^rlins^ 
tOirether with nicely balanced forces, extremely ^li^ht 
moditications in the structure or habits of one in- 
habitant would often cive it an advant-i^e over others ; 
and .^till further m(>diticati(»ns of the same kind vvould 
orteu still further increase the advantage. No count.'-v 
■ an 1)6 named in which all the native inhabitants ue 
now so perfectly adapted to each other and to th(> 
i>hysical coniiitions under which they live, that none ot 
thoin could anyhow be improve<i ; for in all countrit>, 
tie natives have been so far con()uered bv naturalised 
proiiuctions, that the\ b.ave nliowcd forcij^ner? to lake 
irtn posses,sioii of the land. And a.- forei^fnerH ha%-e 
Lhus everywhere beaten some of the natives, we may 
saiily conclude that tlie !!i»tives mi^nt liave been inodi- 
tied V. ith advantage, so hs to \!-:\'\ better resisted su*-)! 

.\s man can produce and certainly has produced a 
jfieat result by his methodirn' snd unconscious meatis 



of «elpcti()ii . whrit m.iy not Nnture et?Vct r M:\n rait .tct 
only on px'rnial ;in(l visible cliiracters : Nature cares 
pot'hiiitr for ;i|'i'earances, except in ■^o far -is tlu'v m.iy 
he useful to any beintr. Slie can act on every internal 
or:ran, .m every shade of constitutional ditference. on tlie 
whole roa<hinHry of life. Man selects onh tt.r his own 
ffoofl; Nature only for that of the beinir which -.he tciMls. 
Kvery selecte<i character is fully exercised hy her ; and 
the heiriiT '> placed under well-suited contlitions of life. 
.Man keeps the natives of many climates in the same 
country ; he >-old<>m exercises each selected character 
in some pecijiinr and fittintr manner; he feeds a long 
and a short beaked pi{feon on tlie same food ; lie does 
not exercise a iotiir-hacked or lone-iegffed quadruped in 
any peculiar manner : he exposes sheep with lotie and 
short wool to the same climate. F^e does not allow the 
most viiforoua males to strutrsrle for the females. He 
does not rigidly destroy all inferior animals, hut protects 
durinj; eacli varying season, as tar as lies in his power, 
all his productions. He often heirins his selection by 
some half Tr.'instrous form ; or at le^st hy some modifi- 
cation proi.niieutenoutrh to catch his eve,or to he plainly 
useful to him. I iider nature, the siiirhtest ditference 
of structure or constititioit may well turn the nicely- 
halanced scale in the struirtrle for life, and so he pre- 
served. Mow tleetinjr are the wishes and etTorts of man I 
!iow short his time I and conseijuently how poor will 
his products be, compared witli t'loso accumulated hy 
.Nature duriiiir wl.oie i/eolotrical periods. ( an we wonder, 
then, that Nat:ire's productions should he far 'truer' 
iii character tlKin man's pro<iuctions ; that they should 
i.e intiii'f'lv • ctter adapted tf> tht' most complex condi- 
tions of life, and shoubl plainly hear tht- slatnp of far 
bi-rher workmansliip .■" 

It mav TiietAph'Ticn 

riv1es:iid that natural sele* tion 

io dailv itid hourly scrutmisinir, throutrhout the world, 
everv variation, even the sliffhtest ; rejecting: that which 
is had, preservintj and adding up ail that is good: 
gilentlyand insensibly workinjj, whenever and wherever 
opportunity offers, at the improvement of each organic 

I i 



beiup in relation to its ortranic and inorganic condi- 
tions of life. We see notliiiitf of these slow rijanjres in 
progress, until the liand of time has niarkt'd tlie lotij; 
lapse of a^es, arul then so iinperftrt is our view into 
ioiii; past tfeoloifical ajjes, tliat we only see that the 
forms of lite are now tiitiercnt from v\ hat they formerly 

Although natural selection can act only tliromj-h and 
for the ff^)^)H of euch heiiij;, yet cliaracters ami >triictures, 
which wo are apt to consider as of very trillin:.'- im|»ort- 
c'ince, may thus he acted on. \\ lien we see leaf-e^tinir 
in>ecta green, and bark-feeders mottled -yrey ; the 
alpine ptarmi<:an white in winter, the red-t-Touse the 
colour of heather, and the hiack-irrouse that of peaty 
earth, we must believe that these tints are of service to 
these birds and insects in preserving them tVom danjrer. 
Grouse, if not destroyed at some period of their lives, 
would increase in countless numbers ; tlu'v are known 
to suffer lartrely from birds uf prey ; and hawks are 
guided by eyesight to their prey — so much so, that on 
parts of the (. ontinent persons are warned not to keep 
white pigeons, as being the most liable to destruction. 
Hence 1 can see no rcison to doubt tliat natural selec- 
tit)n might be most effective in giving the proper colouf 
to each kind of grouse, and in keejdng that colour, 
when once acijuired, true and constant. Nor outriit we 
to think that the occasional destruction of an animal of 
any narticular colour would produce little etfei't : we 
should remember how essential it is in a flock of white 
slieep to destroy every laml) with the faintest trace of 
black. In plants the down on the fruit and the colour 
of the flesh are considered by l)0tanistj? as characters of 
the most trifling im{X)rtance : yet we hear from an 
excellent horticulturist, Downiruf, that in the Iriited 
States smooth-skinned fruits sutler far mure from v. 
beetle, a curculio, than witli down ; tiiat puqile 
j)lums sutler far more from a certain disease tlian yellow 
piuins ; will reas auuLiier ili^e.ise aUA« k-* yeiidw-iiesiied 
jieaches far more than those with other coloured flesh. 
if, with all the a-ds of art, tbet<e sliirht differences make 



I differouce in cultivating the several varieties, 
i.-wuredly, in a state of nature, where the trees would 
have to etruffjfle with other trees and with a host of 
oneiniew, such differences would etfectually settle wliirh 
variety, whether a smooth or downy, a yellow or purple 
fleshed fruit, should succeed. 

Ill lookiiier at many small points of difference be- 
tween species, which, as far as our ig^noraiice permits 
us to judfje, seem (juite unimportant, we must not forget 
that climate, food, etc., probably produce some slight 
and direct effect. It is, however, far more necensjiry 
to bear in mind that there are many unknown laws ot 
correlation of jfrowth, which, when one part of the 
or^^anisation is modified throufj^h rariation, and the 
modifications are accumulated by natural selection for 
the good of tlie bein^', will cause other modifications, 
often of the most unexpected nature. 

As we see that those variations which under domesti- 
cation appear at any particular period of life, tend to 
reappear in the offspring at the same period ; -for in- 
stance, in the seeds of the many varieties of our culinary 
and aiiiricultural plants ; in the caterpillar and cocoon 
stages of the varieties of the silkworm ; in the eg-jfs of 
p(»ultry, and in the colour of the down of their chickens ; 
in the iiorns of our sheep and cattle when nearly adult ; — 
so in a state of nature, natural selection will be enabled 
to act on and modify organic beinps at any a^e, by the 
accumulation of variations profitable at tliat aije. and by 
their inlieritiince at a correspondini; aije. If it profit a 
plant to have its seeds more and more widely dissemi- 
nated by the wind, 1 can see no ^eater difhculty in this 
beinif etfected throutrh natural selection, than in the 
cotton-planter increwising: and improvinjf by selection 
the down in the pods on his cotton -trees. Natural 
selection mar modify and adapt the larva of an insect 
U) a score of contingencies, wholly different from tliose 
which concern the mature insect. These modifications 
will no doubt alfect, throujfh the laws of correlation, the 
structure ot the adult; and prof)uhly in the c^se of those 
insects which live only for a few hours, and which never 



iee<\, a large part of their structure is merely the > or- 
related result of successive changes in the structure of 
their larvjr. So, conversely, moditicatioi's in the adult 
will probably often affect the structure of the larva ; but 
in all csLnes nat'iral H»'k'ctioii will ensure that moditica- 
tioin con8e<]uont on other inodirtcations at a different 
period of life, shall not l)e in the le<ist degree injurious: 
for if they V)6came so, they would cau>e the extinction 
of the species. 

Natural selection will modify the structure of the 
young in relation to the parent, and of the parent in 
relation to the young. In social animals it will adapt 
the structure of each individual for tlie benefit of the 
community; ifftich in conse<juence pnttits l)y the selected 
change. What natural selection cannot do, is to modify 
the structure of one species, witliout giving it any advan- 
tage, for the good of another sj>ecies ; and tliough state- 
ments to this etiect may be found in works of natural 
history, I cannot rtnd one case which will bear investi- 
gation. A structure used only once in an animal's whole 
life, if of high importance to it, might be modified to 
any extent by natural selection ; for instance, the great 
jaws possessed by certain insects, used exclusively for 
o}>oning the cocoon — or the hard tip to the beak of 
nestliiv birds, used for breaking the egg. It has been 
assertea, that of the best short-beaked tumbler-pi;.^'*^^ 
more perish in the egg than are able to get out of it ; 
so that fanciers assist in the act of hatching. Now, if 
nature had to make the beak of a full-grown pigeon 
very short for the bird's own advantage, the process of 
tnodincatiou would be very t^low, and there would be 
'simultaneously the most ri^rorous selection of tlie young 
birds within the egg, which had the most powerful and 
hardest beaks, for all with «eak l>eaks would iiu'vitably 
[)erish : or, more delicate and more e;i-ily broken sliells 
might be selected, the thickness of the shell being known 
to vary like every other structure 

Sexual Selection. — Inasmuch as peculiarities often 
appear under domestication in one sex and become 


bereditarily attaclied to that sex, the «aine fa.-t prob- occurs undor nature, and if so, natural selection 
will he aide to nK.dity one >ex in its fun.-tional rela- 
tions to the other sex, or in relation to wholly dirterent 
hahits of life in the two sexes, as is sometinieH the case 
with inserts. And this leads me to say a few words on 
what 1 call Sexual Selection. 'Hii-* depends, not on a 
stni.-'le for existetiee, hut on a stru-L'le hetween the 
n.ale> for iM.ssession of the females ; the result is not 
death to the>l!,l ccwnpetit-.r, hut tew or no 
otlM.rintr. Sexual selection is, therefore, less riK'orous 
tlian natural selection, (ienerally, the most vi»forou9 
males tho^e which are hest fitted for their places lu 
nature, will le^ve most pn.^reny. li'it ui many cases, 
victory d.-pends not on ireneral vigour, hut on havintr 
special weapons, confined to the male sex. A hornless 
stijr or spurless cock would have a poor chance of 
leaviiiif otfMirinir. Sexual selection hy always allow- 
iua the victor to hree<l miffht surely true indomitiihle 
courage, lenirth to the spur, and stren-th to the wnig 
to strike in the spurred let:, as well as the hruUil co.-k- 
ft.rhter, who well that he can improve his h reed 
bv careful selection of the l)est cocks. How low in 
the scale of nature the law of battle descends, I know 
not; male allitfiitors have been described as tij^htniff, 
bellowiims and whirlintr round, like Indians in a war- 
dance, for the possession of the females ; male salmoius 
have been seen tiKhtiiitf all <iay loug ; male statf-beetles 
often hear wounds from the huKe mandihles of other 
males llie war is, perliaps, severest between the malea 
of polvL-amous animals, and these seem ottenest pro- 
vided With special weapons. 'Hie males of carnivorous 
animals arealre;uly well armed; though to them and to 
others, special means of defence may be -iven through 
means of sexual selection, as the mane to tlie lion, tlie to the hoar, and the hooked jaw to the 
male salm.-n : for the shield may be a^ imporUnt for 
victory, ;ui the sword or spear. 

Amon^rst birds, the contest is oflen of a more peaceful 
character. All those who have attended to the subject, 



ttlnM.' that th»!rp is tlie spvpn'xt rivalry hotwpen the 
iii.iU's of niiiiy «jK'cip-» t(» attrnrt \i\ MJiiirint; tli'* fcniales. 

I lit- nick-tfirusti (•< (Jiii.ina, hir'lsof J'ararli^o, and some 
(itlnTs, ron^/rt'tnte : ami siicfcsHive males display llipir 
/ •'•j.'f'oiiM jiliiiii.i;.'0 .111(1 jierform straiiLT antic-s ln-foro fl-.e 
>fi'»>s, wliicli, Ktiimiiiii.'- Iiy a.s sjn-rtators, at last <-hoo>c 
'II- iiio^t ati :Miiiv»» jtartiMT. 'J lio^e who havo closply 
.iitfiidefl to tiirlx in rontiin'inorit well know that tlipv 
iili'ii take iiu!i\ i()iinl jircfercnc*'- and dislikes: tliiiri 
^:r l( Hcroi: li i- d»'s«riU»d Ijow one [dcil jteacoi k was 

'niiifiiil . attr.ictivt' to hII hi.- hen hirds. It may <i,iidi-l; to attriliute any oth'ct to such apjiar- 

'illy wwik iiuviiis : I (■.•uiiiot hrre enter on tin? details 
i.i'i-cssary to siijiport this view ; hut if man can in a short 
•■'Ml' ^ivc ele^'ant ('arri.'ij.''i' and hcautv to his hantams, 
.!• cMrdii:^'' t'» hi- >-tand;ird ot he.iut}', I can see no foed 
rci-ni, lo duiild that tcniale hir<ls. liy selecting, durinsj 
ttio ,-'i!]ds of irencratioiiK, tlio mo»t mclodiou.'^ or heaii- 
rr;;! inalc-. aciordintr to their t-t;iii(l.ini of l>e;i'ity, 
Ti).i;li'. jTixIuce ;i marked otfecf. I strontrly sii'-jioct 
that soiiie well-known laws, with respect to the pluuiat'-'^ 
u( Ilia!.- and female hirds, in cnmpitrison with the 

II iirn:i:.'e ol the yoiiiiir, can he e.xpiaiiied 'in the vietv 
ol pli,m;i^'^e hiNJiiir !>eeii chiefly modified hv se.\ua! 
sclectioii. actiiiLf when the hinls have come to the 
!''it'ilin_'^ aire or diinntj the l)reediM!r sea-on ; the 
r'liditic.'it'ons thus prt'diiced heiiitr inherited at corre- 
-pondiiii: .'It! I - or seasuns, either hy the males alone, or 
liv l.e rii.ileK ,iiid females; but 1 ha\e nut sjiace here 
to enter on this siiKjeet. 

liiiis it is. as 1 hcl'eve, that « hen the males and 
r''in;.lfs of any animal have the .s.ime ^'eiieral hahits 
• '} li.o, hilt ditier in structure, colour, or ornainont, 
-' 1 ii dirterences have heen mainly caused hy sevual 
>electi(m ; that is, individual males have liad, in 
-uccessive ueneratiouh, some slitrht advaiitatfo over 
otfiiT males, in their weapons, means of defence, or 
<:«'ius; and have transmitted tfiese advantages to 
!. '.••!■ male otlsprintr. Vet, J would not wish to attri- 
bute all such sexual differences to this agency : for we 







i:^ I 2.8 

1- I-" 


1: 1^ 





r^S 'ochestef. Me» Yo'k U609 US* 

= ^ ' 6) ♦aj - 0300 - Phone 

^S: 716) 288 - 5989 - Fo. 


' ' 1 ; ; 

R2 ON TUK cRUilN OF S1'K( lES 

-t>P noculinrities arisiiitr and hpconim- .itta,-hp<l tn th.? 
„.U- M.x i:. o.r .Inmestic '.. ti.o watMoin male 
rarritT-.. Imrn-lik.''>>H iii tn.M-u,k>..t certain 
fowU ctr.), whirh ■^«> ."iiHiot iM.liove to I..- citlier u.otul 
tt, tl„. rual*.. in hattV, or rittnu'tr... to tl.»' femaie.. 
We ^.'0 ruialoirous .•;.>(- uihI^t tiatun-. tor instanre, U-^ 
tuft of li.ur on iho hnM,t ..f tl.o turkoy-.o.k wlnrh ran 
i,ar<llv ).o .MtluT us.'hil or ornru.uMitil to this t.irU , - 
,:al...-'.l, l.a.l th.' tun appo.ire.l an. iff domestiratioii, it 
would have l.ecn rallo«l a iTioii-tro-.ty. 

Uluxtrntious <M tn>- "rtinn oj SntHrnl S.b'rtum.- \n 
order to muki' .t clear how. as ! believe, natural selec- 
tion arts, I mu^t U- i.ertn.ssion to one or two 
i„,au-..Kirv ,llu>tratK,..s. !..-t us fike the ca.e o a wo . 
whieh pri'vs on various animals, se.-unni: some t.y tratt, 
so:ne I'v ^ireuu'th, and hy lleetness ; and lot us 
Mn,i...<e th.a the Tu'etest prey, a deer t.,r instance, had 
fr.liM anv .-lian-e m, t!u, country iucraised ui luimbers, 
„r that other prey ha.l decre.i^.ni it. tiuinhers, durir« 
1, it smson ..f the" Near when the wolf is hardest presse<i 
t„r food. i can under sueh eircumstanres see no 
reason to dou!.t that the swiftest and rtliinmest wolvea 
,,.,,,1,1 ha^e .ho Lest chance of surviviiur, :'>"1 -^^^ 
pn..erve.l or -elected, - provi.led always that they 
retained .tretiL^th to master their prey at tins or at 
soTMO other peno.l of the year, when they mitrht i>e 
' ' - - ' I can sec no 


♦ ,, j>rey on other aininals. 

, reason to ,!oul.t this, than man can im- 
prove Mie tleetne-s o. hi> greyhounds hy caretul and 
, selection, or hy that unconscious •e.ection 
which results from each man trying' t<. keep the bent 
d,.-. witli.Hit anv of modifyine the breed. 

Kwn without anv. han-e m fh.- proportional numlwjrs 
of the animals on which our woU preye.i, a cub mi^ht 
■■,e horn vnth an innate tendency to pursue cerUm 
W.nds of nrev. Nor can thi^ In? thou;:ht very im- 
•,rohahle; no- we ot\en .d.serve ureal .iiner.-nce^ in tha 
natural ten.lencies of our d.mie-tic animais ; one c^., 
tuT uistan.e, takin- lo .atch racs, another mice; or-s 




fAt. ar-nrdintf to Mr. >t. Joiitj, hriii^rme hfinif winifed 
traii'e. a"n>h«r liare-* or rai»i»;i.-<, ritui ani.'iior fiuiitiru on 
riiarsliy erouinl and almost niijlitlv i.-alrliintr woiMlcM-kH 
or vTiijics. nit? temieut-y to latch raU rather tiiaii 
mice is knnwii to 1)6 inliertttl. Now. if aiiv ^liifht 
iriiiate cfiaiiKf* ot liabit or of structure l>o!.«ihteii an 
individual wolf, it would (lave the best ciiaiice of 
xiirv i\i;ii,' and of leJivnii,' ort.-.[(rniir. Surnt* nf lit* vouiijr 
wouhl probably inherit the same hanit.s or Htructure, 
an<i l>y the rrpotitiun of t)i.s jiroce-^s, a v.f.v variety rniifht 
i>f» rorijie<i which would either supplant or coexist with 
tfie jiarent form of w(df. ( )r, a^riiin, the widves ia- 
habitii.t: a mountainous di-rrict. ami those frcijut-ntiii^ 
the lowlaii'ls, would naturally be forceil ;o hunt di.Terent 
j.rey ; and from the continued preservation of the 
individuHls !>est fitted for the tv*-o site>, two varieties 
miirlit slowly !»e formed. riie>e varieties would cro«« 
and blend where tiiev met : but to this .subject of 
interTossinjr v*«' shall soon iia-. e to return. I may add, 
that, accordinir to Mr. Pierce, there are two varieties 
of the wolf inhabitinjf the ( aLskill Mountiiins m the 
''nite'l States, one with a litfht irrevhound like form, 
whicli pursue^ deer, and the other more iuilk-,, with 
^ilorter letrs, v*birb more frei|uently attiicks the 
shfpherd - flocks. 

i.*'t us now take a more complex case. * ertain 
phiots excrete a sweet juice, apparently for ii.e sake ot 
eliminatiniT ^;omethini» injurious from their s,-ip : ttiis in 
etfected by trl^iid,-. at the b.ise of the btii'ules in -ome 
l>'_Miminos«*, and at the back of the leaf oJ the oriniion 
biurel. Tliirt juice, tlu)u;,'h -mall in -juantitv. ih 
i-'rcedily soutrht by insects j^t us now suppo-e m 
little sweet juii »• or nectar to be excreted by the inner 
!..-.(■- of the (letals of a •b)v*-er. in this ca-e i^st < tn i;i 
seekiiijr the iH'i-tar v*o!il(I .-^et ciu-tcd with jwdlen, ami 
'Vol. 1(1 certainly often trans|nrt tin- poilen from one 
t!o'.<-er to tile ft.irma of another liower. rheli<;wers of 
iwo distinct ithiividuals of tlie same .■•peces would ttiuu 
ev- crossed ; and the act ot cro-?-iinf, we ha»e trood 
rBa#on to beiievp (aa will hereafter •<»• niore fully 



allud»'<l to), wf>:;l(] prociurp \ory vit'onius Hee<lliii/v, 
wliK li roii'i'ijiH'iillv uiiiild liasc the \n-Mt «'l:,i!ic«' of 
floun^liiiitr ami surviving-. >imif ot t)ip<e ni'e«iiinir^ 
woulti pri.liHl)!)' HiluTit tlic lUM-Lir - ♦■xcr»'t!ii{f power. 

or iifi'tario'', :iij<l wni' h t*xrret»'ii mu-! nei uir, wdtil.l lio 
often. -si visited by iiihects,aiid wmilil l>e (ilteiie-it crossed ; 
ami ^^l ill t!i»' liin;:-riiii >Noiilii tj.iiu the ui'j'er hand. 
riu)-.e ll(>u.'r^., ,•ll.•^(<. Miiii'h iiad tlieir iJtaiiifiis and pi-^tils 
pl.ieed , lii ridaLion to llio ^ize and t.aitit- of tlu* 
pari)' ular in!^f»:tti whicli visitt'd tlieni, •>(» as to fasoiir 
in Hin detTet' the tran^portal td" liieir imllen from 
llower to fiu.MT, would likei*i-t' i)e favoured or •«elefte<i 
Wv initriit liavetaiseii tlie c.t.'^e of in--eets viHitiritr liov\er> 
fur the n.ike of coile<'Mnir polien in'-teaii of ; and 
as poi.eii 1- t'lrnu'd for tiie side oii't-et of terhiis.ition, 
its destruction nppears a siriijde i<i-» to tiie plant ; yt-l 
if a lilllo pollen were e.irriei', at !i;-t ocea-;"r,ally and 
then iiaiiitu.illy, hy the p(dleii-<ievourini£ ni-.t.,'t- from 
IhivM-i te flower, and a cro^s thus etn-eteti. aithouifh 
tiine-te'iths of the pollen \M-r*' <ie-tro\fd, it iii!L''ht still 
i)e a areat L'^ain U> tlie ; ami those individuals 
whi< h prodt'ifd mo'-e an' more pollen, \:\i\ had lar^jor 
and larger anlhers, wduld he seie. teil. 

W 1 ei- our plant, iv this p.-,„-(.^^ ot the .ontinued 
pre-iT'. atinn or natural selei'tion of more aiid iimre 
attr i.'t; .e r''\* ers, (lmI heeii rendered hi:,'h!v attraeti^e 
to iii-ieet'. t!,ev would. unin(eiitioii.i!l\ on their jiart, 
rej.'ulari\ lari \ puUeii irom liower to tlower ; ami that 
tlie\ ean ni<i>l enectualiy do this. I could easily sho-v 
bv many strikiii:: instame^. i will trive onl\ one -not 
ah a \t'rv striking'' c;ise, hut as likewise iliusM.itinij one 
gtei> in tiie separat'oii ui tio- sexes of plan'.s, pre-eutly 
to lie alluded to, >(i!iie htdiy-trei-' near i< ily niaie 
flowers, whieh i)a\e tour st.;iTnens protim-inj r rather 
small <jUintitv of pidieri, and a rudimentary pistil ; 
other hidiy-iries jie.-ir oiiK feinalp tlowers : t*ie>e have 
a full-si/.ed pi-til, ami four stamens with shruelled 
anthers, in whiih not a triain of pollen ean he (ieterted. 
Ha\'in^ tiuHid n lerM.uc tree exactly siity yard* from ? 




male trpo, I put the (itiffnias of twenty riower»«, taken 
from ditferpnt hraiirliPH, (imior the microijoope, and on 
all, without eireption, thcrp were pollen-urairiH. and 
on some a profuMon of polU'ii. An tiio wind liad set 
for several liayn from the female to the male tree, the 
pclien roiilil not tluiH have Ueen carrieil. The woather 
li.-i'l tieeii colli am! 'mi-itoroi.-i, ami therefore liol lavour- 
aldo to !i>'t'-<. nevcrthele^h evcrv feni.ile tlowt-r which 
I exannin'.l had been etf^'ctually fertili-''d hy Uif hee«, 
acc-ideiit-ill V d.istcd with pollen, havimf tiown tVom 
tree to tree in search of n»;»t;tr. Hut to return to 
our irii:t^riiiarv "'a^e ; as soon as the plant liad U'en 
leiidered so hurhlv attractive to injects that pi>ll»'n 
w.M re;:\i!arlv carr;t^l from ilower to ilower, another 
pro'-tv-« lutriit commence. No naturalist ilouht-t the 
advanta^'-e of what lias heeri i-allnd t!io ' phy«ioloiriral 
div!-i(ui of l.i'iour'; tienre '■w> may heiie\e that it 
would h»' .ifiv-intaLO-ous to a idant to proiiure stamens 
ilone in me llowt-r or <ui one w}iole [•iant, iinl p'.^tiU 
^ioTle 'n another (lower or on anotlu'r ]ilaiit. In pianti 
under culture aiid place<l under new conditions of life, 
ioriietimci th»' nia't) ortraijs and sonu'tinu'S the tetnale 
oitransj heconie more or less irnjiMtetit ; n<m- if ^e 
sup{M)sc this to (x;cur in ever <-a »li':ht a deirreo under 
.'ii'ure, then a8 pollen ia already carried retruiarly 
fii'in Mower to tlower, an<l as a more coTiiplete separa- 
tion of the Pexes ot our plmt would he a>lvanLaireous 
on tlie pni'.ciplo of the division of lahour, individual! 
with ttii< rciuiency more and tnore incre;i.-ed, would (>« 
continuallv favoured or seiccU'd, untd at lasi a com- 
plete separation of the sexes w(»uld })e effected. 

l>'t U9 now turn to the nectar-feed iiiif insect.^ m our 
iinairi'' irv <a.«e : we mav su[)po-o the plant of whieh 

se ha'-e hcen -•' >wly incre.'.-'iiii: the nectar hy roritTiued 
select ion, to le a common plant ; in<l tliat certain 
lii-ectH d^]MMided in maui part un ita r^ocLar tor food. 
! could ifive many fact.*;, >howi!!tr 1m. w anx'.ou.s Wees are 
to s;ive time ; for in.-'anie. tlieir haliit of cutt'fu; hole,s 
and Kuckiiijf the iiecL;tr at the lwi."-cs of wrtiiin liowers, 
•viixli they can, witli ? very little more trouble, entei 






by the mfhith. Hcarinc S'lidi farts in rniii<l, I nm ^pe 
no reason to (loii).l fiiat ;in a("ci.icnt;il deviation in the 
nize ,.M(] trtriri nf tli,. (.,„ly or it the curvature ■-.iid 
length of the 'ete. , tar t<iO s!ii:iit tn i„. 
apjire.iated l.y hh, iniirh* profit a heo or other in-e. t. 
BO tliataii in(i:\i.l:iai vo rharacterised ur.-jhl he aide it] 
ohtam it< food moie <)iiii'kly, and -o fiav© a better 
chance ol" livi'ip and lea\ inj; (Jeseen<lar;ts. Jtj* desi end- 
ant.s would j.rohaldy inlierit a tendenc- to a similar 
sli^Iit deviation of stnirture. 'Ilic tiil.e.-'of the coroH.-a 
of the eoinrnori red and inran;ale cl-.ver*, ('I'rifoliiim 
pratense and incarnatutn i do not on a h;isly glance 
appear to diiFer in lentrth ; yet the Inve-hee can easily 
suck the nectar out of t}i<' incarnate clover, hut not 
out of the .•onimon re<; clover, which in visited l>v 
hurrddeiiee- alone; >o that whole fiehis of the reii 
clover oiFer in vairi .ui ahundant sui>ply of precious 
nectar to the Idve-hee. Thus it rni^riit l>e a ;rreat 
advantaire to th. hi\e-hee to liave a s'.i-htly lonfr,>r or 
ditterently constructed pridioscis. On the other hand, 
I have Jouiid hy experiment that the fertditv of clover 
depends, on l.ces visitiiit,' and nioving- parU* of the 
condia, so .us to push tlie pollen on to the 8ti:rniatic 
surtace. HtMue, aiiain, if humhie-hees were to hecme 
rare in any country, it mitrht he a {rroat advant.Xi:.' to 
the red < lover to !ia\e a t-hortcr or more deeply divided 
tul>e to its corolla, so that the hive-t»ee could Ms;t it.s 
flowers. Tlni>. 1 can understand how a flower and a 
bee iniirht slo^sly liecome, either .simtilt.aneously or ..n, 
after the other, modified and adanted in the nio>t 
perfect manner to eacli other, by tiie contituied pr.- 
Hervation of individuals presentintj mutual and slitrhtly 
tavourable deviations of htructure. 

I am \\ell aware that this doctrine of nati rai .^elecv 
tion, e.\ernplificd in the Ml)o\e imaginary in-tances, is 
open to the same objectioiis winch were at first ur^ei! 
a-ainBt Sir ( harie.s Lyeli's noble views on 'the modem 
chant'-ot. of tlie earth, as illustrative of (reolotrv ' ; but 
• e now seldom hear the action, for instance,' of the 
eoast-»a\es, calle;i a triflinjf and infitiTiifira. I caus.*, 



when ai'|.!i('ii to tln' oxcav.ition nf triciintif v.illpys or 
u» tlu' tormatioii of (lif li«ri>'osf luics nt iiiliiinl cliffs. 
jN?»ti!nil ■JcitM-tinii can act o.ily \>\ tin" pri'M-rvatiun and 
BC'-iiniiilatioM of i!itiiiitf'?.iinally -iin.-ill inluTite<l nunl' 
ticatioiis, pach j.rofifaMe to the j'rt'-iorv«'<l \,o'\nn ; anil 
a>4 mo'icrii ir*->>lf>ixy h.-w aliii'j>t ii iiii->ht>il nuch vihms as 
the oTcavatiofi of a yreat \all<'y liy a ^i(lul^• diluviai 
wave, -() will'iral Ki'hvtion, if it i>o a triie princinle, 
Lariinh thr tiolit-f of the cotitinin a creation of iu".v 
(<r;i^ariio tx'iiii:^, or of any ^rcat and «u<lclen inotlification 
Hi their structure. 

On the hitfrcnjitijig nf IndinditnU. — I must here 
introduce a s)iort •liure>si(iii. In the cose of animals 
md plants with ^.eparateil ^^'xes, it is of course obviou3 
that two individualw must al«ay:»(with the exception 
of thti curious and not welI-uii(ier>tood rases of par- 
thenoirenesis) unite for each hirth ; hut in the ca.'w of 
hermaphrodites tliis is froni olivious. Nevertheless 
I am strongly inclined to helieve that with all hernia- 
plirodites two indivitliialn, either occasiiinalic or haliitu- 
ailv , concur tor the reproduction of their kind. I'hiH 
view WH.X first .^ujjire.-ted by Andrew Kni^'-ht. We 
liliall presently see its im{>orL'ince ; hut 1 must hero 
treat the guhject with extreme hrevity, thoutjli I hav.' 
the materials )>repar(>d for an amjtle di>cu.«»i(in. AH 
vertebrate aniniai.-., all .nsect^s, and some otiier lar^e 
grt)upH of animals, j)air for ea<:h birth. Modern re- 
search has much diniini>!uMi the nmnber of .supposed 
hermaphrodite>, and of real }iermaphr(»dites a lart,'e 
numl)cr pair ; that i.s, two individuals rcirularly unite 
for reproduction, wliich is all that concerns us. Hut 
still there are inaiiy hermajdirodile animals which 
certainly do not haiiitually pair, and a vast niajuritv 
of plants are hennaphrodites. What re.uson. it may 
He a«ked, is there for supposinc in these rases that 
twu individuals ever concur m rejirod notion .' A^ it ie 
iinpossiiiie here to enter on deuiis, 1 must trust to 
«)me general considerations alone. 

In the first place, ! have collected so lar^'e a body of 






farU, Hhowinc, in acoonlaiire with the almoMt univpp«| 
}>elit'f onircfiiors, tliat wi»h animals and plants a croM 
}»ot\vet'ii difioriMit varictifs, <»r l«'t\vfcn individiialH of 
tlu^ ^-imo variety Imt of another str.iin. irives vitrMur 
and fertility to tlie otf-prinif ; and on th(? other )iand. 
that r/oM' interhreedin^- iliiiiini>hos Mj-oiirand fertilitv; thf-i- tai't- alone incline me to !ie!ir\e that it i<i a 
^--eneral law of nature (ntterlv ii,'-norant ♦iiouirh we he 
of the ine.ininL' "f tlie la\i ') that no or^Mnic heintr >«<-if- 
fertili-fs it>flt fnr an eternity of trenerations ; hut that 
arro-i-- with anotiier individual is occasion. iilv -perhaps 
at very lotur interNal- indi.-j..ns.ih!i\ 

< )n the hclief that this is a law r)f nat'ire, wi> lan, I 
think. ii;i(ier>tand several larire ola--e-i of fu'ts, >uch 
as the lollioviiiir, whhh on anv other \ieu nre inex- 
plieahle. Kvery hvhridi/er knows duvv u-iravioirahle 
expM^ure ro wet is Ut the fertilisation of a li.rwer, vet 
what ,1 inul'itnde of (hiwers )iave their anthers and 
sti'.'inas filly e\j)o-i'd to the \\eather ! Init if an oira- 
sional .r.i-ii ho iixii-pensat.le. the inllest freedom r..r 
the entranr.' of pnli.Ti from another individual \v;ll 
explain this -tatt! ot e\'pn>nre. more esperiallv as the 
plant's own antliers and |)i-t;l i:<'tierall>- stand so eh.^e 
toirether tiiat >«di-fertili>ati«>n s.^ciiis ahno>t iiuniUilde. 
Many ilowers, on the other hand, have tiieir ortrans of 
friictihcation ,h.-ely enclosed, as in the ;rreat tiaj.i'.io- 
naceoiii or pea-t'amily ; hut in sfwral. perhaps m ail, 
such flower-., there is a verv curious :id;i{it;ition fietween 
the structure of tlie liower and the manner in uhich 
hees suck the nectar; for, in dointr this, they ether 
pu-h the )'(u\er's own pollen on the sti.rma, or hnntf 
poilen troui annthcr limver. So nece»ary are tlie 
visits of hc>'s •(! papilionaceous flowers, tliat I have 
fiund, hy expennionts puhlished elsewhere, that their 
U'riility is trreatly dnninished if tliese vi.-its ho pre- 
vented. Now. it 1^ scarcely possible that Ix-es should 
fly from flower to ihaver, and not carrv [I'dlen from 

• '. •" ■■■■■i- i;:v^-- iiT-;:, .t.- • •fiif-.c, o; rf;o 

plant. Ihes ^ill ;ict like a camel-hair pencil, and it i-i 
quite sulK.icnt just to touch Itie anthers of one f'jwer 


■^V:>-. '•;•:^J^^^i';y^,:tJJ|^ 



and then the ctiirma of another with the ««nie brush 
U> ermiire tertilisatum ; but it mn-^t not he sui«|M»»e<l 
that l>e<'s wouM thus prtxluce a multitude of h)i)rid« 
JM'twtM'ii distinct sjKHies ; for if ytui briujf on tlie same 
brush a jilaiit's owti jwilh'ii and pollen from another 
sjiecies, the former will lia.e such a prfpotent erfect, 
til it it will invan.ihly and i,om].let«'ly iJ-'-trnv, as ha« 
hveu shown by (i.trUier, any in!iuen< c froiu the foreign 

^\ h»'u the .-it.inien.s of a liowor xuddenlv !<prin<f 
towards the pistil, or nlowly move one after the other 
towards it. tlip mntrivante seems adipted sololv to 
ensure self-fertilis-ition ; and no dout»t it is usefif for 
this end ; but, the a^'ency of inserts is often re<juired 
to I aiiv the stamens to .-priii:; rorwar-i, as K 'IreiUer 
has shown N» \iv ilo; case with the barberry ; and ia 
tlii<. very trt'iius, st-ems to have a sp«'cial - ontri- 
vaiice for srlf-fert:li-.-ition, it is well known that if 
clo-ely-allied forms or varu-ties are plante<i near each 
other, it is hardly posMhle to raise |>ure see<iliiiirs, go 
lar;;ely do they natiirally <-ross. In manv other cnsos, 
far from there l)einjr any aids for M*lf- fertilisation, 
there are special contrivances, as I couid show from 
the wntin^fs of (. C. Spre!ii,'el and from mv own 
oliservatiuns, which etfectually prevent the st'ifma 
reoeivine pollen from its own flower: for insUmce, 
in l^iU'lia fulireus, there is a re-ally beautiful and 
elaborate contrivance by which every one of the infin- 
itely numerous poUen-ifranules are swept out of the 
conjoined antliers of eacli riower, befdre the stiirma of 
that iiulividual liower is ready to receive them ; and as 
this ilower is never visited, at least in my ^nrdt^u, by 
insect,s, it never sets a seed, thoutrh by [ifacini; [.uUeu 
from one fbiwer li-i the stitrma of another, 1 rai:jed 
plenty (tf seedliiiL^s ; and ^llilst another sjiecies of 
I/olieiia trrowintr close by, which is visiied by bees, 
see<ls frwly. In \ery many other ca>.».s, tbouifh there 
be no special mechanical contrivance to prevent the 
stit'tiia of a flower receivin:: ts own [xillen. y(>l, aa 
C. C. Sprencfel has shown, nun as i can confirm, cither 






iht .iii'-tii'i'-' hur^l licrmi' tn.- .,• -i i i ii ri'inly for tfitil- 
i»«.it;i»ii, <ir tin- •-iuiri.'i i-^ lo.'idy ttj-fnri' tli»* [i()!l»>n of 
that )!iiwer i- rtudy, no llii'-c jilatiU liave in f.irt 
M'j»ar:it«'il f«exeM, amJ rnu>t li.-\liitual!y Ik* < ro«i«.«'d. How 
Ktr;i!._M' are tlifse facts ! Iliw stran;:e that tlie |>ollt«ri 
and .^tii^riiatic "irfacH of t!iu -uiio Jiowi»r, ttiouirh phict'd 
Ko rlosi" toifplli.'r, .l^ if (or ihe vitn juirito-r of self- 
fcrtilifNation, «.houl(J in so many fa-i'- lie mutually 
•i-oli---; to ci' 1; otlif-r '. H"« -imply arc ihe-p farts 
eiplaiM'd on til" vic'.^ of an <i<Ta>i'ii,,il rro-n witli a 
diHlincl i:idividiial la'injf ad\ant;ii(fOii!* or nuiisjjon- 
«ai<l«' ! 

If sfvt-ral v.iru.'tif'* of llit.' laliliairu, radi-<h, onion, ami 
of Mtrno otlitT plant"., 1>« alinwod to K»»cd near each 
otlioi, a l.irtre niri Ontv, a" I have found, of llit' seedlinjo* 
ihuh rai->;d will turn out iiiontrrel.i ; for instance, 1 
raisod 2."i.'{ s«»odlinu cahha;rt's from some plants of 
ditferent variolie-. f^rowiiiij near eai-h other, and <>i 
those only 75' were truB to their kind, and some even 
of tl' were not |)erfc<f !y true. Vet the pistil of each 
cah .ifo-flower is Burmunded not only by ita own "ix 
stamens, hut by those of the many other flowem on the 
same plant. How, tiien, comes it that Huch a vast 
numher of the seedlin;rs are mongreli/ed ? I gus{»ect 
that it must arise from tlio pollen of a distinct tv/n>^y 
haviiiij a prepotent etfect over a flower s own pollen ; 
md llial ti^s is pari of the general law of >rood heine 
derived from the intercrossinif of di'^tinct individuals 
of the same species. W hen distinct *7>»<tc* are crossed 
the c^-ks* is dirtv tly the reverse, tor a filant's own pollen 
18 alway* pre[>otent over foreiirn j)ollen ; but to tlti* 
subject we sh.ill r«>turn in a luturo chapter. 

In the aise of a trijrantic tree covered with innumer- 
able tlowers, it rna\ be objected that pollen could 
seldom tH* (Uirried iVom tree to tree, and at most only 
from flower to flower un the s-ime tree, and that 
flowers ou the same tree can be considere<l as distinct 

iJlUo itiu<ti^ i*uiv in it iitnit<-«i Sriinc. i i'viie^c liiis 

objection to be valid, hut that nature h.vs largely pro 
Tided atra:n^t it by giving to trees a stron? tendency 

^^^-.?m^t^€^ ^ ^r^'^^'*^y--'w: ^f^im*^'^ 

«* ' * f-Lj^it^., Jut J 




M. > flower- -iiri He|iarat<'d m-xch. Wli.'ii th** vexr^ 
irt- M'par,iU-.i. .wlhoi.^;!, tli,- tn;il»' nun tviuilv f!(,vvi>rh 
nav l.e prtMiiir*'/! ..ii th»» -ame tn-e, we rin ««.»> 
..i;liMi inii»t l>i' rtv'.J.irly farru-<i from tir.M,.r t.. Hmver 
umI thw will j^ivp H M'.r . fiaiirr of j,„ll.'u U-mi,^ 
•'<.;i.-.i(,iially rarrie.l tr<'«' tn tri«r Tliat trr«i« 
irt'I.'i!jfii,£T tn all Or.lerh liav.- thoir Kt-xcv more oHni 
««eparal-.! tha:. rtthor f.laii!..,, 1 fin.l t.. \»- the ra-t. in 
ihi!- country ; an.l at my rp(|iie8t I >r H.Mjkor Ubijlat»-d 
ifii. trtH;.s „t N,.v* /(.aland, and Dr. Asa (iiav lliosfl .,/ 
Ih. I niti'd SUit.'s, and tlip r^Kult v*;u ;is 1 anticipated 
On the other hand, l>r Hooker ha>, recentiv informed 
'lie that he finds tliat the rule dr>eH not hold in 
Australia; and I have made these t«w remarkn on the 
Hexes of trecH sitnnly to call attention to the suhjeot. 

lurninir for ;» very hrie' space to aiuniaN : on the 
land there are some hermaphro<iites, as land-moUusca 
aud eartli-worms : hut these all })air. As yet J have 
iiot found a sin^rlo case of a terrestrial animal which 
fertilises itself. We can understand ihis remarkable 
;act, which offers «o stroiiir a contra>t with terrestrial 
plants, un the view of an occasional crong being 
iiidisiMMisatde, bv considerinjf the me.liiun in which 
errestrial animals live, and the nature of the fertilising 
element : lor we know of no me-ans, analok'ous to tiie 
action of insects and of the wind in the case of plants, 
'•> which an occasional cross .ould he t-lFected with 
terrestrial animals without the concurrence of two 
individuals. Of aquatic animali*, tliere are many 
self-feniiising hermaphrodites; but here currents in 
tJie water offer an obvious means for an occasional 
cross. And, .as in the case of flowers, 1 ha\e as yet 
tailed, after consultation with onf of the }.-ir},'t.>t 
•luthorities, nanjf-iy, Professor l!ui!,-y, to dLscover "a 
smt'le or ;in tu<rtn.t[''n..drite animal with the or^ns 
of reproduction so perfectly enclosed within the Unh, 
that access from without and the otca-sional infiuenci^ 
ui a distinct iiidivuiual can be «hown to be physi.-aHy 
imjK)ssible. ( irripede.- lontr apjx'areu t.. me to present 
a r .SH or very »rreat difficulty uiiJer thi* point of view 



hut \ liav(« )non «ina)ilod, by a fortunate charic*, 
el-owl^Tt* to jirovp tliat two iiuliviiliiaU, thoiiu'fi f>otL 
»r»» H«'lf-N>rtil>".iritr iiprni.ipliriMlit*'-, <to •<iiiif>f iriuM rr(»H«. 

It rmist liriw •^tnirk nt<)>*t iiatur.tli-^f s m* R ntraiitre\ m 'Im* cas*" of Imth .inini.iU aiul pl:itit«, 
<<i»ori«'«* of till' Kanio fitnily ir.d I'vi-ri ot ttio -.iine irfinis, 
tfioiiifli atrreeinj: ••lo-'ely witli racli otImt in alinoht their 
■.vhi)l«« or riJiivit on, vet arn not ran>lv, lomt" of th«>m 
ii«rrMa|)lir«>i|it«'s, anil "tornc at llcin iini-i'\'ial. lint if, 
i!i fai't, all i!«Tni-ij'hro(iit'»s -lo ocra-ional'v iTiten-ros^ 
with other imiivuliiaN, the ditfori'iiro h»'f*i<'n luTiiia- 
jitirtnliti's an'i ^pt'cipx, a>. far at* fuiiftioii i-« 
con«'oru»*(i, l;««i-onu's vorv hiii ill. 

From thi'si' KtMt'ral c'on.'«i(ierat!otH arul troin iho 
manv i«i»»' fru-ts whith I have coil»». te<l, hut winch I 
ain not hrrt* ahh- to iriw«, I am «troriu'ly incl'it'tl to 
^u^p<*«•t tiiat, hoth 111 the vot:»'tahle and aainial Ki'i^f- 
'Ji,in». an o( rational intercross with a diHtitirl individual 
ii a law of nature. I am »oll aware that there are, on 
ilii.-i view, many cases rjf tiifficulty, some of which 1 arn 
trying; to invest :::ate. Finally then, we may conclude 
lliat in manv oriranic heint^, a crosn Iwtween two 
mdivid'ials is an ohvioun ncessity tor each hirth ; in 
rnany others it occurs perhaps only at lontr intervals ; 
but in none, as I 8us{)ect, can Helf-fertilisatioii »fO ou 
for porpe^iity. 

(Sriirii>t'nivft ftn-o^irnhU to Satiirnl f^flfctxon. — I'hiH 
\» an extremely intricate Huhject. A lartre amount of 
LnheritJihle and diversified variability is favourable, but 
I believe mere individual dilierences sutRie for the 
work. A liri'o number of individuals, by g-ivinjf a 
b«tter rhainc for the appearance wthin any tiven 
period of prolitaMe variations, w:ll compensate tor a 
!e>M»r amount of variaiiility in each individual, and i*, 
I bflieve, .in e.xtrtmelv important element of success 
'Hiouj^rh 'laturo yrantrf viist period.s <tf time tor tiie 

infiotiiiite jicrioci ; for :\.m all urfcraiiic l>eine« are ntrivinif, 
it may be *aid, to Kiuze on each jiUure in the t^ m^my 



lit nature, if »nv 'Uie Nj>«»rio« d<w*.i not UM-omo m*Mlitic<l 
HM'I ini[)r«)ve<i iii a corrt'««p<it»«innf il»>irri'c with i\n coin 
|M'ii?<'r«i, it v*ill tMiuri l>r pxterimnatrd. 

In niaii'M niotho<liral wlettioti, a lirtM»<ler •««'l«>»t«* for 
»;»rin' ii('tin'«> «ilii«yt, nii'l fro«» iiiterrroHsm^ will n*1i<>11\ 
Mtiiji hJN wnrk. Hut wlii'ii rii.itiv riu'ii, witl.oui nitrni) 
mn to alter lh«" WrtMMl, have a iiwirly rommnn ntainl-ir«i 
of perfcrtinii . ami all try to i;«'t ami l>r(MM| (rum l\\v 
lii'Mt aiiiiiitU, iiuicli iniprovtMiiefit ami trnxitu-atioti 
mirt'ly liul nlowly follow from Huh uiiconsoioim j)roc«>s- 
of nelertion, notw■ilil^taIlliiIlir -x l.irist* nmrniiif i.t 
iTossiu;; With interior aiiimaU. Mm- ? will he m 
nature; for within a ronfine'l nrra. with norne pl.tre i. 
it< polity n'»t "o jierteitly occupieii a-* niicht he, n.itiira: 
selerfion will alwavx teml to [in'«erveali tiie imii. iilu;il- 
\riryirij( in the riL'ht (iirectinri, ihoiiL'h in different 
'h'irrees. 8o a^* U-tter to fill up the uiuxTupieii piare. 
I';it if the area he Liree, ii» several di'-trift.*' will almost 
(•; rtninly present ditierent coiiditionH of lite ; umi thiMi 
if natural •«eleoiioii Ik» inutinyinjf and imprnvinjr ^ 
!.jMMie« in the neveral di-trirfs, tliere will he inter 
.rofi-ing with tlie o'her individuals ot the same speeie- 
on the tontines of earh. And in Um- case the erie«l«. 
of intercrossinjT tan hardly he eounterhalaui-ed hy 
natural r;ele<tioii alwayrt tendini: to mo<li:i, «!! ihe 
indivifiiial- in each district in exactly the s;iriie manner 
to the conditions of each ; for m a oontinuou-. area. i!ii- 
physical (■(Miditions at lea-t will jfenerallv I'radn.iU- 
ii*ay insen&ihly from one iii>tri(t to :i:u)ther Ihe 
mtererossmtr will most affe<"t those animal- wlneh unite 
for eiich hirth, whieh wander much, and which do not 
Ureed at a very quirk rate. Hence in atiirnals of lhi> 
nature, for instance in birds, varieties a ill jreneraliv 
l>e confined to separated countries; and tlds I t.elieve 
•o \ni the oa.-*©. In hermaphrodite or^:ani«n"s wiiirli 
crosM only t)cca>ionall"-, and likewise .u aniujals wnicii 
unite for each hirth, hut which wander little and which 
riiii MirrPA»© ^i <* vt*rv rspiu icti^}, s new aiiu »nipr»'iV6u 
vurit'ty miifht Ik» (juickly formed on any ouo ^paX, and 
rnujht there maintain it>ielf in a body. m> ihal ^hniever 



int«»rcrn«8incr took pl;ici' wo-ilr; ]>o chiefly brt.M<«en the 
iiidividu:ils <»f" tho same ww ■.ariptv. A local variety 
wlien once ''iiis formed miirlit ■siiKfiOijiierifly ^lowlv 
Hj>r«'.i(l to other flistrirU On the al.ove principle, 
Tiurscrynioi; always prefer trottiiiif seo^i from a l.irtf.- 
boiiy of ;)iaiits of the <amo variet-y. i'j> the <-harir-P of 
intercrossing- with other variftie-^ '-^ tliu-i lessene<]. 

Kv.Mi in the .-.-iso of -Inw-hreciint: animalu, which 
unite fi>r oruli '.irtli, w^ mij-;t not overrate the effects 
of intprrrosses in retar<linj^ natural i,;'loction ; fur I 
can \.nuu a rf»n^idprat-!e rat^lotr,,,, ^f facts, (sfmwuii: 
that withui tlie -ame area, varieties of the 'samo animal 
can_ lon;r rtmaui .iistinct, from haiintin;^ different 
stations, from hreedintr at sliirhtly diifrrcnt seasons, or 
from variotiea of the same k;ud prcforrinif to />air 

Intercrossiriff plavs a very important [)art in nature 
in keepintr the individuals of the sajne species, or of 
the same variety, true and uniform in character. it 
will ohviously thus act far more ofTicimtly ^ith those 
»n; mal< which unite for (vich birth ; t.ut I 'haM> already 
attempted to show that we have reason to hdieve that 
oc<asional intercrosses take place with all animab and 
witli all plarjta. Kren if these take place unlv at Ion? 
mtcr\a!s, I am convinced that the yountr thus pro- 
duced will piin so much in M:,'our and fortility ovor 
the offsprintr from lonjr-connnued self-fertilivition, 
that they will have a l>etter chaiice of surviving and 
prop;u.>:it;i:: the'r kind ; and thus, in the lonsr run, 'he 
influence of intercrosses, even at rare intervais, will 
be trreat. If tluTo exist orirani'- beirij^d which never 
intercross, uriitormity of character can ho retained 
biuontrst them, as lonir as their conditioTie of life 
remain the Mime, only tlirouirh liie principlo of inherit- 
RTice, and throutrh natural selection dc^ royin^ atiy 
which depart from tho proper typo; ! ut' if their 
conditions of life cl anue and thev uiidertro inoditic^tion 

— :*■ :i.. r .1 . I ^. . . .. 

!.:;:.:. ..;..^ ,;, .;;.;. .iClJ'" Caii uCui'ieii to iil»']r IllOO'ineo' 

offspriMff, solely by natural selection preserving the 
•aia>' fav,.iurabie variations. 


9. -5 

Isolation, al«<), isan imjiortant olemont in the {»riM es»i 
nt natural seloctioii. In a ronfita-d or isolate<l area, if 
not vory larce. the organic atnl inorjiranic con<!itio!i7( ot 
life will /rt'iierally l>e in a yreat ileifrt-f uintorni ; so 
that natural •jpU'ctinn will tend to nnxlifv all tli** 
indivitluais of a varyint: ^pffies throuthtmt Mie ir»*a m 
th»» HaiiH! manner '.n rpla'ion to the siiine coiiiiiiions. 
Interrrn-,st>«, also, with tht- individuals of the name 
sj cries, which othenv;<,' would have iiihahited thi- 
surroundintr and dirfiTiMitly rircutn-tanced (ii?,tricti<, 
will hf> prevented. liut i.'i<datioii prohahly acts tnnre 
effirientiy in clieckintr tlie immigration of hetter 
adapted ctriranisms. atter any nliysical chantre, suth a>« 
of climate or elevation ot the land, etc. ; and tlius new 
pla^- in the natural economy of the country are lett 
open for the rUl inhahitantM to 8tnif«-le for, atid 
become a<lapted to, through modiiicatiotH in their 
structure and constitution. Lastly, isolation, hv 
cht Ainjf immi^^ration and -onsefiuently ci>m{»etition, 
will (five time tor any new variety to 1)0 «lowly im- 
proved ; and this may sometimes \ni of imi»orLanoe in 
the production of new .si>ecie.s. If, however, an 
iKoIated area he very Hmali. either from loinjf «ur 
rounded l)y farriers, or from having- very peculiar 
physical conditions, the total i.umher of the individual 
supported on it will noces.sarily he very smaU ; and 
fewness of individuals will i;reatly retard tiie (tro<luc- 
tion of new spei-ie^ throutrh natural selection, by 
decreasing the chance of tiie appearan<-e of favoi;rr»'de 

If we turn to nature to test the truth of these re- 
marks, and look at any •^m:\\] isolated area, such ,i.s lu 
oceanic islanrl.althouL'h thetotai number of the specie? 
iiihaliiting it, vill be tound to be small, a** we sliall ^ee 
in our chapter on treographual dntribution ; yet of 
these specuvs a very large proportion are endemic,— 
ttiat is, have beei: prod!i(.e<l tiiere, ind nowiiere elt>f 
lieiice an 0C'6aiiic isiaml al iiril Muhl -'••eii;» u» uavf 
been highly favourable for the |)ro<luctic»n of new 
!-pecie«. But we may thus greatly de<eive oursfllve^ 

I', Ml 



for to ascertain wlicthcr a sni.ill isdl.itcd ari'a. or a 
liT'jo n|i(Mi arra iil-..' a coiitiiiiMil. li.i- lii'cii most f.'ivour- 
aiii«' for tho jiroi'iifiKiii ot immv orj/anii' torins, u«' ouLrlit 
to inako tlif r()nniari>.<pii \\ iiliin lime-^ , and thin 
w«' arc in. .iii.ti-lt' ot (ioui^. 

V!t li'i'i:ii! I 111) ii'it (iowht tliat isni'itidri in ot ronnider- 
»lile iin|)ortanc** in tnt- proiiiKtin:; o! new Kjifi-ifs, on 
tin' \vli(»li' I run iicliiifd to l«eiunp that htr;:t'tif's> f»f 
arra i« oi trMirt- iiii[Mirtanc»', riioro especial 1\' in the 
prodiK'linn ot ^!.l•^i('s, M);i(ti will ]ir.i\t' rapahie of 
eiKiurinir tor a h'lij jicriod, and of ••|iri>a»int:.' \vi<i«'iy. 
Tliroui/lioiit a ;:rtMt aii«l o]n>n at«'a, not oniv w.W thrre 
be a In Itc: rhauif ot lavoiuahlo \'ariaiions a ri >• i ; i ir from 
til'" larL'f jiiiTiihcr of iinii\ iiiuais of the ^aiiic -iit'cios 
tlicii- -iipjmr c'l. 'vit tlic rondit jous of litf are ini'iiitely 
corii|'if.\ troin tlp' iarj.'*' nuinher of alre.idv exi^tinp 
BpecJc^ ; and it some of these many spn le- liei onie 
modi*iod uid iniprove<l, others will have to tie improved 
in a corrt'spondinir deirree or tliey will he e.vterminaied. 
Kacli iif>v inrni. aho. as soon a-* it ha.- heen mucli im- 
pr«>vt'(i. will he aMe to -;ireaii o\i'r the open and ron- 
tiniHMi- .".rt-a. ami \<ill thiis conic into romiic'ition with 
main others. Ilcuce more new plaec- uill iic formed, 
■ijd till* rornt"..-, ition to till tiieni«ill he ni. re sc\ere. on 
n laruc th.i'i on a small and isolate] area. .\Iorco\ or, 
preat ar»':i>. tlioiiL'ti no\\ continnou-i, ow injT to o-<il!a- 
tions ot !( cl. vmII ottcn h;»\e recent iy e.\istc<l ni a 
hrokcn roi! iitio'i, so the sjood eticct.s of isolation 
wiii t.''encr..ii > . to a ecrtain extent, h.ive roncurred. 
Finally, i concl'iiie that, although 'nriil i^oi/itcd areas 
prol>a)ils ii.i\e h('<:i in some rc-pect.- hit'iii) ia\ouraMe 
for the jirodtictioti of new '-].e(ies. yet that tlie t onrse 
of inoiii'H ation will trenerailv ha\e heen more rapid on 
lartTc areas; and \»hat is more iniportant, the 
new funiis {)rodiieed on lar;/p aieas. which already have 
heen virtonoiis over inanv competitn.'-'i, will 1»^ thot* 
that will spre^id most widely, will g-ive rise to mo«t new 
>arieiic- ,ti i >pcci(^, anu «iii iiiii- piav an Mii|Mjrt:int 
{►art in tlie chan^'inc history of the organic world. 

^V e ean. perhajw, on these views, understand gomt* 



t»rU which will be airaiu ailuded to in our chapter ou 
geo^aphical distribution ; for instance, that tin; pro- 
ductions of tlio smaller coutiueiji of Australia have 
formerly yielded, and apparently are imw yieldintr, 
before those or" tli«' Jarfrer Kuropjeo-Asiatic area. Ihtis, 
alno, it is that continental productions liave everywhere 
hecdme so largely naturalised on islands. On a small 
island, the race tor life will liave been letw severe, and 
there will ha\o been less modification and less exter- 
mination. Hence, perhaps, it comes that the flora of 
Madeira, according,' to Oswald Ueer, re>enibles the 
extinct tertiary flora of Europe. All fresh-water basins, 
taken to^'elher, make a small area comiiareti with that 
of the seii or of the land ; and, conse.iucntly, the com- 
netition between fresh-water productions will have been 
le«B severe than elsewhere ; new forms will have been 
more .slowly formed, and old forms metre slowly ex- 
terminated. And it is in fresh water that we find seven 
genera of (ian»»id ti.shes, renniants of a once pre- 
ponderant order : and in fresh water we rind some of 
the most anomalous forms n»»w known in the world, 
as the Ornithorliynclujs and Lepidosiren, which, like 
fossils, connect to a certain extent orders now widely 
separated in the natural scale. 'Hiese anomalous forms 
may almost be called living fossils ; they have endured 
to the present day, from havintr inhabited a conrined 
area, and from having' thus been expo^ed to less severe 
coni petition. 

To sum up the circumst-inces favourable and uri 
favourable to natural selection, a8 far as the extreme 
intricacy >f the subject permits. I (onclude, lr>okintr 
to the future, that for terrestrial pnxluctions a lartje 
contineuUil area, which will probably under^'o manv 
oscillations of level, and which consequently will exb<t 
for lon^ periods in a broken condition, Ls the most 
favounible (or the production of many new forms of 
life, likely to endure lon^ and to spread widely. For 
tJie area rirst existed as a continent, and the nihabitants, 
at this period numerous in individuals and kinds, will 
have been subjected to very severe competition. U hen 






coiivprled \t\ -lihsi'liMir*) into larir*' separate islands, 
tlnTf will still I'.v-t many imiiv iiiiial.-. of the -lame 
Bj»«-cii«s on cicli : intt'nros>in:: on the rontinos 
of thtj ran^o of each s|H'cu's will tluis he cluM'ked : 
atler j»h\-i. .1! ciianiie- dt .1:1 v kin I, immigration w)ll 
lie pniventeii. so tiiat new j. faces in tiic |m)1iIv of each!nl will have to ' • lilleil tip liv moiiiliiatioiis ot the 
oi<l nihai.i:ant> ; ana time will tie allowed for the 
varieties in each to hecomewoll inodi'ieil and periecied. 
When, hy renewed eie.ation. the i-i,ind» >.li;ill !,<. re- 
converted into a continental area, tiiere w:ll a^ain 1h» 
severe cornpetit ;on ; the most fav<»ured or iinproved 
varieties wili he enahied to : tiu-re will i.e much 
evtini'tion of the ie>s improved forms, and the relative 
proporiional iiiiml>er« of the various inhahitants of the 
rei.>ewed (ontineiii will a^raiii he chan;:ed ; ami airain 
there will i.e a fair heM lor natural selection to im- 
prove still further the inhahitants, and tlius produce 
new Hjtecies. 

That natural selection will always act with extreme 
Blowness, 1 fully admit. Its action depeinls on there 
l>eintr places in the polity of nature, which can ho 
better occupied hy some of the inhal)itants of the country 
uiiderjfouit: nioditication of some kind. The existence 
of such places will often depend on [diysical chantrea, 
wliich a jrenerally very slow, and on the immieraliou 
of lietter adapted forms havintr been checked. Hut the 
action of natural selection will prohaldv still oftener 
dei'Ond on some of the inliahitants hecomiiiij- slowly 
modified ; the mutual relationi* of many of the other 
inhahitants heint: thus disturbed. Nothing' tan he 
prTected. unless iavourahle variations occur, and varia 
tion itself is ni)parently always a very slow process, 
llie process will often he L'reatlv retarded hv free inter- 
cro.ssniii. .Many will exd iim that these several causefl 
are amply sullicient wlndly to stop the action of 
natural selection. I do not believe so. ( )ii the other 
Land.l do iieiie\e thai natural seiectuui aiw.ivs acts 
very slowly, often only at loriir intervals of time, and 
(fenemlly ou only a very few of the inhabitants of the 





lamo rpfrinu at the «ianio timi*. 1 furf)it>r h«'li(«\o. tlml 
tliiN very .-i(tw . iutiTriutTent ;ii-tioii ot natiinii solcriioii 
acronls pertettiy w»'ii witii wliat trfolotry toils u.s of 
the rat*! and niainuT at vvluri, the mlialutaiits of tJiin 
worifl has*' < liain.'t'<l. 

SiowttuHit^h till- process of ■seiectinn fii.,v !«•<, if feohlo 
Tiiaii can do niut ii bv fiis ()>m»>rfl of MrtiriiMi M-leftiois, 
i cat! see no limit to the aiiumiit of chaiii.M'. to the 
it'.itity and niiiinie ron)[.li-xity of the coadiiiitalions 
bftAcfii all ortfanic heiMtTv, one with anoili»T and 
vviiti their |ihysic;il oonililions of iife, wh;rh may he 
er'eited in the iont: course of tim»> tiv nature - power 
ot selection. 

h'.itinrtion. — 'i'his Mihieet will he more fully di-cusseii 
m our chapter on (ieoiotry; l>ijt it mu.-t he here alluded 
to from \mns intimately connected with natural nelec- 
tion. Natural selection acts M>'ely throuali the [ire- 
>iervation of variations i:- ssime way ad\ai.r.u:eous. w liich 
consequently endure. Hut .la from tlie hiyii geometrical 
ratio of increai-ie of all ortranic l»ein{fs, each area it 
already fully stocked with inhahitanLs, it follows that 
an t^ach heleote«i and favoured form increa-ses in numher, 
so will the le»iH favoured forms decrease and hecome 
rare. Rarity, a^ jfeolo^y tells us, is the precursor to 
extinction. We can, also, see that any form repre- 
sented hy few individuals will, duriiiif fluctuations in 
liie seasons or in liie number of its enemies, run a trood 
chance of utter extinction. Hut we may ffO further 
than this ; for as new forms are continuiUy and slowlv 
Winjr producwl, unless we believe that the number 
of specific forms jfoes on perpetually and almost iu- 
derinitely increuhiriiyr, numl)er8 inevit:ii)ly must hwome 
extnict lliat the numl>er of s[M*<itic forms ha** not 
indefinitely increa»ed, jreolotrk shows us plainly; and 
indeed we can Hee reason why they should not hav« 
tiius iucreaHed, for the numher of places m Use nohtv 
of nature is not indefinitely great,— not that we have 
any uieauBof kuowintj that any one retfion has a^ yet pot 
itN maiimum of 8i>eiien Probably no region is a^ yet 



fully St ocke«l, for at tiu^C aiK3 of (iorxi U(({)o, where more 
H[>«cieK ot' plaiiu are crowded totfetlier tliaii in any otlier 
(jiiartiT of the world, some foreigTi plants have become 
uaturaliMMl, without causiiiir, as far ;is we know, the 
♦'xtin<'tion of any iiativ*'^-. 

Kurthernuirt', the -jn'cies which are most numerous 
in individuals will iiave the Itest chance of producintf 
wittiin any triven period favourable variationn. \\ e 
have evidence of this, in the facti* jfiven in the second 
cha,>ter, showing that it is the common s{)ecies which 
atTord the i:reate«t numl>er of recorded varieties, or 
incipient species. Hence, rare species will be less 
• juickly nioditied or improved within any ^^iven perio<i, 
and they will conse<juently \>e beaten in the rrwe for 
life by the modified desceudant« of the commoner 

From these several considerations 1 think it in- 
eviUthly follows, that as new species in the c«)urHe of 
tinu' are formed throu^fh natural selection, others will 
become rarer and rarer, and finally extinct. The form* 
which s^and in closest comiMJtition with those under- 
j:oiut' modification and improvement, '^"ill naturally 
suffer most. An<l we have seen in the chapter on the 
!Stru:;;rle for Kxi>toncc that it is the most closely-allied 
forms, — varieties of the same species, and species of 
the same ;jenus or of related genera, which, froni 
haviut: nearly the same stru( ture, con-ititution, and 
habits, jreiu'rally come inu» the severest competition 
with each other. Consequently, each new variety or 
sp«'cies, durini: tlie projf ress of its formation, will g-ener- 
ally pre>s hardest on it. nearest kindred, and tend to 
exterminate tluni. We see the same process of ex- 
tcrniiii ition amoiiifst our (]omestic;iU>d productions, 
throuirh the sele( tion of improved forms by man. Manv 
curious instances could l>e triven showintf how quickly 
new breeds of cattle, slieep, and other animals, and 
varieties* of fbtwers, take the place of older and iiifj-rior 
kinds. In Yorkshire, it x hi-<torically known that the 
ancifiit black cattle were displaced by the lou^-homs, 
and that these ' wore swept away by the "hort^horus ' 



(I fjunte the words of an .lerii-ultural writer) ' m if hy 
Home murderou- postilence.' 

Iht-rryencr (\f f'hnrniter. — I'lie jtriiiriple, which ! li.ive 
lesitfii.iltMi hy thi^ t^rm, i> of liieh iniport.iiu-t* on niv 
theory, and expl.-iiim, a« I helievo. wnpnil important 
tarts. In the first phirp, vari»>tiex, ••vpti strnMirly- 
iriarkrd onofl, thouirh ha\iiii: somewhat of the chanicter 
.if s|>e<ies- as is «hnwn hy tlie luipt'lcHs douht*! ii; iiianv 
I ;ise«« how to nmk tiieni- yet rcrtiiiiily differ tro-ii eacfi 
other far less than do jr<"»<l and distinct sjiecies. Never- 
tlieless, accordiriif to iii\ view, varieties are species in 
the process of forrnatinn, or are, as I have called tliem. 
incipient specie,s. How, then, does the leaser dirferencc 
tH'twt'C!! varioti*";- become auirniented into the trre.iter 
difference l>etween sj>ei'ies - That this does haliittially 
liipi>eM, we niiist infer from most of the innumerahle 
speces throutrhout nnturf preseiitintrwell-m.-irked differ- 
fMice>» ; wh«>reH.s varieties, tlu' sipfMised prototvjM-^ and 
parents of future well-marked «{)eries, presefit slight 
and ill-<letine<l differenee-i. Mere chance, as we may 
lall It, iniirht cause one variety to differ in some char- 
acter trom its parents, and the offspring of this variety 
airain to differ from iL« parent in the very same character 
and in a g-reater decree ; hut this alone would never 
account for so habitual and lartre an amount of ditfer- 
«'nco an that hetween varieties of the same sj)ecie8 and 
spe<'ie.s of the same eenus. 

A.S has always been my practice, let us seek liirht on 
thi.« h'ad from our domestic productions. We shall 
here lind soniethini; niialo^'ous. A fancier is struck 
Kr a pijreon havinjr a i^lij^htly shorter })eak ; another 
ti.'iCier iH struck hy a piijeon havintr a rather lonircr 
><vak; and on the acknowlc-di^ed principle that ' fanciem 

00 not ,ind will not admire a fiifdium standard. i)ut 

1 ke extremes,' they both no on (as bas actually occurred 
Aith tumtder-iiiifeoiis) choosirm and J> from l'!r<!s 
^vith lonu'er .and loiiijer be-aks, or with .shorter a:,d 
short* r ^>eaiiH. Airain, we may suppo.-e that at ati 
'<arly period one man preferred swifter hor*Hs , nnotuer 


ON THK <»IU(;iN (»K sPK( IKS 


"Lrniijrt^r .irirl rnnre luilky Jiorsps. rii<M';iriy 'liffcretice* 
would b»' very fcliirlit ; in ♦he rnurs*' of time, from th»i 
oontiiuie<J ^< '..''tioti of «vrif>«'r tHir-cfS hy kmiiio hrff-iors, 
aiiil i)t stro!itrt»r onc-J *>v '>tii»>rx, t!i»> lii'ffrf'm'p^ would 
''OCOTno t»T»»at»»r, atid \»viuiil t't* rinUvl -i«4 t'ormin^ two 
ont>-i>r(>««(l-, ; fin.tlly. jiAcr the l.ip-^c of c«'riturips, the 
«nh-hr('o<l-i would iMvonip rotivortrd into two w«ll- 
extahli'^hptl aiicl ili^trict hn>«vlrt. As the diff»>rpiire9 
gjowlv 'H>c()rm> irrjvitcr. the inferior anim.ii.- *ith inter- 
mtHli.'ite I'haract.TP, tiomtr iifithnr very swift nor very 
gtroiitf, will have hoeu iiOiri»'i"t<Ml, and will h.ive tendoil 
to di'>a[>[ppar. Here, then, we wo in man's* prodnrtioni 
Hie a«ti«in of what may l>e r.iiieil the principle of diver- 
ifenro, caiiHintr ditfi-retifOH, at hrwt barely appreciahle, 
steadily t<"> increase, and the t»re«Mis to diverire in -hir- 
icter hoth rrom (vach other and from their common 

Hut how, it may ho a^^ked, can anv analntrouM prm- 
C';ile apiilv in nature.' I *>elipve it cai, :ind d.'H»x ap|iiy 
most elhiit'iitlv, from the ^^imple cifcum'-taru'e that the 
more divermiuvi the descend. mb} from r.nv one P[)ecie8 
hecome in ptnictiire, con-titntion, and hahiw. hy so 
niinh will thev he hotter »'iri}>led to ^^ei/e on many and 
widely d-.versitied places in the polity of nature, and 40 
be eiiahled to ir.c.ease in numherp. 

W'p <'an clearly <re this in the rase ot animals with 
fiimplo haSirs. lake the case of a carnivorouij ..uadru- 
ped, of which tl e numher that, can i>e supported ui any 
cniin*r\ h.'is lontr ''u,'" arri%e | ?it i^^ tuil averr»t:e. if its 
natural powers ot increase he allowed to act. it can 
Bucceed in iiicreaxinif (the country not underffoini;- any 
chantre in it« ••onditions; only hy its varvine" descen- 
dants seuinif on places at present occupied hy other 
at'.inials r some of tli.»^ni, ( t instance, ^leine enalde«i to 
feed on new kinds of prev. either dead or ih-.e ; som« 
inii.ahituiii' new stations, chmhing' trfe«. tre'j'ientinif 
water, and some perhaps h«'comin<f le~>< i-arnivorouji. 
1 he more dntTsitied m hati:ts ari'l stri;cture thf 
dcM«cendants of our carnivfirous animal t>ecame, tha 
more pLice'- thev adiiIiI he enafded to -vcupy. ^Vh** 


^ffe^^i/v- lL^l^M.J^:^2^m£:!^^mk 



applies to <>•.»• ;uiir»ril will npi Iv t!ir()ii/i!i"it al! l in« 
to .'ill .iiiimnU tli.if iH, it' flicy vary- t(»r (>t^t'rvri^e 
natur.'il >««'Ie( tiori crin flo TinthinLT So it wi'l >«c with 
plai'ts. It hnt Ix'tMi t'vjit'nniciitallv j»r<ivt»<i, t)>at it" a 
plc»t of groiiml !>»« «i<nvii with oiio ^p^'rit"* of ifr^t^M, and 
a similar pint 1>«> <(i« n «itli v««\ cr.i! ijistiu<t potior* 
of irra^^os, a i/rt'ati'r luiiiiluT of pl.intfl ami a greater 
weiirht of dry lierlia;;'** can tlm>4 lie raisp'l. I 'le ■vima 
ban tx'eii found to Imld trootj wlipn tiriit f)no vnrioty 
and tlit'fi s»'\<'ra! rnixod varu'ti«»8 of wlieat havi' ht-f^n 
sown o!i equal spaces of iiroiind. Uciicc, if any one 
operios of yfa**'* wre to gn oti varvinc, and tliose 
varieties were oontinjially ^elertcd whicti ditft'red from 
each other in at all the rt;ime manner as di^lirict specien 
«nd jfenera of trrasses differ from each other, a {greater 
numU>r of individual plants of this spe<'es of j^rasH, 
incliidintr its modified d»'sceiidafit-', "oiild .succetxl in 
livirnf on tl'O satne p'ece of irn)Ufid. Atid w(> well 
know lliHt each site<ies atid e.ich variety of ^Tnss is 
annually so\vni;i- almost countless seeds ; and thu^, u 
it may he ^aid, is strivifijr its utmost to incrt-a-e it<t 
numhcrs. < (tnseiiuetitly, 1 cai'tiot douht in the 
-nurse of mativ tlu.uvuids of tret^eratinns, tf'o r.Hvst 
distinct vanet;cs of any otie ppecies of trr-i-"*" «■ ilj 
always have the l)ost cliatice of succecdirssr ars'l oi m- 
cr«'.'s'tii; in niirnlKT". atid tlius of siipplanti/;:/ tl.*' less 
distinct \an»'tie-i; ami %arii'ti>'s, wImmi rendo'ed very 
di-t'iict from each oth»'r, tak<> the rank of «j *'c;es. 

'Rie truth of the pr:ti< ip!e. thtt t!ie t:re?t'.--t amount 
of life can he supported hv ^ireit di^ersiticitinn of 
structure, is seen uide"- many natural circunistafuTS. 
In an extremt'ly sm:ill ar»'a, especiallv if tre«»ly ojicn to 
immitTat.on. and wh.'re t!ie contest h«'t«eer! iMdi\iil')al 
and individual must he severe, we a!wav« find jreat 
diversity in it,s inliahitant.s. For instafue, I found that 
a piece of turf, thrt'c f«*<^t hy fieir in «i/e, whifh had 
(<<^en ei[>ose<l for m.anv yearn to exaitlv the .same cf)u 
'iitions, supported twenty ■species of piints, atid thefie 
oelonired to eijrhteeii irvnern and to eii:lit orders, which 
shows how inuch the-e plants differed from each other. 


o\ ruK oiu(;i\ OF spKciKs 

So it iH Willi tlip pl;iiit«i and •ii-«>cU on ^mali nnd 
uiiifonn islet-; ; and so in mn.ili |MitiiiH of frosh wafrr. 
Knrriiers find that tliov cati miv-*' mo>t food }>y a rotation 
of iilaiits hcloiiiririf to tlo- most different ordon» : nature 

tolliiw-. \\]ia' in.i} l.c .anfi! ;i >iinu lt.ln4•.lu^ tntaticn 
Most of tlic inini.iN .ti;i1 p! iMt.s wliirh li\«. clo-p round 
aii\' small jiu-.e of trround. could liw on it (supfiiisirn: 
it not to ),.' in any ua\ jn'<- iliar in iN naturf), .md may 
In* said In In- -tnunL' to '.].,• utniuvf to !i\«' tinTi- ; iiut, 
it is sfon, tliat wiicre tlicy cnino into tlif do-.'.: com- 
prtitiori uifli carfi otli.-r. tht* ;i.hantair»"< of div»>rsinc.i- 
tion of HtriK'turr, witli tin- ncconipanyiiitf dir'^f ■•fn »■>. of 
Kaliitand cnnstitution . drfcrrnin*' that tlie Mili.ilntant"*, 
\vh!fh thurt jostle ea. d otlicr most .jo-.-lv. f.liai!.ii-. a 
irrnrral nilp. l>»•l.iM^'' to what « .• .•.ill .i::f.T(>t,t (.'cucra 
and orders. 

Die -.line priiiri[.!e i>; .een in the natiir,'ili«.a-;on of 
plants lfir(Mi::ii i):,iu> ;i_eiicy in foroitrn lands. It 
mitrht liave l-een .-vpected that the jdauts wlm h have 
su'-C'eded in lioio-nina' naturalised in anv land would 
jTonerally have l.een clo-ely allied to the indiffenes ; 
for tlu'.-e an- roinruoiily looked at as speciallv created 
and ailaptod for their o.^n rountry. It tnitrht, also, 
p«'r':aps ha\.' heeri expected that ' naturaliM-d pl.mts 
would h.'ive ! eloiiifed to a few jrroups more especially 
adafited to certai-i stitions in tlu-ir new homes. Hut 
tho case is verv o ffercnt ; and Alpli. I)e < .uidolle tian 
well remarked in his irreat and adniira(d<> work, that 
th.ras {jairi l.y naturalisation, proportionally witl; the 
numl'er of the native trcnera and >jKM:es. far more iu 
new trenora than in new species. 'I'ii cive a -int'le 
in-tance: in the edition of |)r. .\s,i drav's Manual 
o/ffir Horn of thr Xorthrrn f'nif'il SfHtp.\, 2<"><t natunlise*! 
nlanl- are enutneraled. and these helont-- to Id:: !,n-nera. 
\\'e thus see tiiat these nat iirali-cd plants are of a 
hiirhly nature. i'hey diifer. iiiorto\er. to 
a hiTire extent from tlie indiirenes, lor out of tae 102 

irAr 1 «ir>u ]^.^. il...., !jiiV ..... ^_.. „_,. . i ^V~ 1 

^T- .-^ ,,.. ,. -- ..;::-.;; .... -tritf;.; it;t- : r: ;::t-r:- it;;;; 

t^eriouti, and thu-> a lar^re propor'.ional aoii.iiui- i.- uiade 
io the ct'uer.: of these Staic 



Br (•(•nxHieriii:; thf natiir»« of tin' itl.iiiU* or airmal* 
wliiih hnvo t<trin:irl«''1 Huftc-i^fully with tlip itulici'iie* 
of .iiiv country, a'ld have tln-ro hrcorne n.itiirili«r<l. wre 
mav jrain Homo (•rii<l»> nlra in wliat rnautipr <Mtriu' ot tlie 
n.ituj'ji would }i.i'.o to i<«> rii'i.l :;cil, iti or>ltT to train \i\ 
iilvantaifp ovpp tlip otiipr rlative^ , and «»• may at l»'<Kt 
satt'ly iiifjT that divor-itiration <>f <trii. tur«'. aniotiiit- 
Mii/ to iM'w i:«'neric ilirienMicox. would t-f iirot'.t.iM« to 


Ilif adv.intau"' of divfr-iificrion in tlio inh.iluf.inifl 
of th<' same rivi"ii is, in fact, the -^arnr as that of ti,^ 
,divMo]( dni.-ion of iahour in tho npirans of ftie 
-anu> mil; . idual l«o<lv a suhjprt so well clu. l-i*#>'i 1., 
Milhp |-..i.^ards. No (ih vsiuintn^t douht> that a -imiiacti 
I I ipted to diircut ve^»'taiil»' mattt»r alone, or lU'-h alone, 
ir.iws most initriment from th^sp suh^'aiuj's. >o in 
■h»- ifcneral »'cnnMtiiy of anv iaml, the rn<>rt« v*i<|f]v \iu\ 
[•••rfpitly tli«' animals ami plants arc <livfcrsiii«»d for 
(li^orriit ha'iit-i ot jifi-, >■<> will a trn-.iter ncnilu'r of 
indi\i(iuals h»' cajiriKlp of flioro supportiti:.' tlu'riis»«K»-f<. 
A Het of .ininiafs, with tlieir ori;ani<»;ttioti t)ut l;lt!p 
dnorsifie*!, i ould hardly compote witli a set mor*' 
p*-: ;'(•( 'Iv divcr^ifiod in structur*'. It ni.iv he doui»t«'d, 
for HisUmi-e, wlictlier the Australian marsiipiaU, which 
arc divided into j^-roups ditferiisiT hut liitle fmrn eacii 
iithtT, and u'ehly rcprt'^fliuinir, as Mr. \\ itrrliouse and 
nthcrs have remarked, our carni\orou«, n.minant, and 
rcHiOnt mamnials, could succes.-fuliy compete with these 
well-pronounced order-. In the Australia!] mamrnals, 
we -ee the pnn ess of <iiversifn ation in an early and 
ii)' oniplete st;itfe of development. 

.\fter the foreirointr (iirtcussi'Ui, which oucht to have 
hei-n much amplilied, v\e may, i 'hiiik, assiime tliat tije 
inditied de-cendantj* of any one cjK'cies w ill succeed hy 
-o ruui'h tlie hetter as they beci.Tne more ili\er->it.ed in 
struciurc, and are tlius e!ial>le<] to en<To.n h mi placeti 
>ccu|iied hy other hein;.'s. Now let us !»ee liow ihii 
ruitipie of heilefit btJiHji deiivf-d fruni d;vpr(,riii« •>» 
. haracter, coni!>ined w'th the principle;- of natural neleo- 
tior and of extiruiiou, wiU teud to act. 

! fir, 

• 'N ! UK OlUlilV (>h M'K* IF> 


HiH nrcompaiivinu' fiii'/ram ■.*ill ,-iid ^m in uii.Iir. 
-tuilun: fliijt raflitT |t»'r|>l«'itirip Huliu't-t. IjpI .\ tn I, 
r»>jir»'-fMl th« Mjir-ifM (»t n j^rrm** l;iri.'f> in <\n uivri 
•uuMlry ; lliniHO xpi'iii's .iri» "ijpiiu^iMi t > rc-pfniiip p.ich 
>lhfr iti iiru*'| iIi'ltim*-. n* is so ;/»'r)i>rr»!lv fho i'.'Imc 
M n.ifiiro. nnd m h r»'[i'-t-.«'!iT»',| ni tfip (h.i;rram i»v 
•ill* IfttiTs •itiiiKliiiL' at UM»'>|u;il (li«UiiireH. I ha*f» -aid 
.1 iJirtri) irt'tiim, iHTijiisfl we have **t'«':i in the -»'<i»n<l 
rhipter, fhrit on an ;ivt' nuiro u' t|io njKM-ies of 
i.i'-ife ceripra vnrv ..f -mall jr»Micr:i ; ;iriii tti»> varv- 
.•■,j specu'r. iif the lar^rf CMt-ra pn-jcnt n trri- itiT nuin*>«^r 
W varu'tien. U e have, hUd, ^..,.(1 that tlie «ipf( io<!. 
'*iiich art! the rnminorie-Jt ami tin* niost h )ilelv-<lif1uHe<l, 
varv n\<>ri' than rare -pfcies w;t[i ri'st rictt-d rin::oH. 
Let ( A I 'le a fdtnmdn. widflv -diffused, and var\ mif 
Hpe<-;e'<. h.'i(cii.'Uiu' to a treruis lar^re in its own i-nutiirw 
The little fan of di^eririi'i; dotteii lirieN of iineijual 
letJt:»h-< prnri»ediinf from i A), mav represent its varvinjf 
.iJi-prinir. I he variaMo:m are Mi[>po-ed to U» e\t rernelv 
liiiht, hut of tlie nioNt 'iiverHiticd nature; thcv are 
not Bupi>o<!e<l all to appear mmnltaneoimly, hut -dten 
after Ion;; intervals oj t!:iie ; nor are ^)\t>v all supposed 
•o endure ^or e'lual periods. (»ril\ those variations 
whi<'h are in some way proiitalile vriii be preservtMi 
or nat:jrally -•iliM'fed. And hfre the importance or 
tiiB i)rin<'iide of henetit \>oiii!; derived fro!,i di\ enro-icp 
if fhararter romeH m; for this wili teneraliv lead to 
llie most different or diverfi-ent variations (rep-,.>;eiited 
hy tfie outer dotted line*;) h(>i:iL: preserved and aeeu'iiu- 
lated hv natural seleition. W hen a dotted line reaciies 
one of the hon/nntal lines, and is there marked \>v a 
sinall nu!ii'i«Tt"i letter, a sufhciei'* amount of variation 
IS supposed to hav© heen aecumulated to ha\e formed 
1 fairly weU marked variety, xuidi as wcvild he thou;rht 
Torthy of reeord in a .sv«teniati<" work. 

Hie intervals hetwet'ii tlie iion/ontal lines in thi- 
liaj^ram, may represent earh a thous-and jrenerations , 
nut <t would have ^n-eri hetter -f r:uh hi.-' rrpre.-<',;tp<i 
ten thous.Tud i:»^nerations. .\tter a thou^aiid t't'iiera- 
'.oa>. speoies i \! is supposed to have produre*! t*o 
- 'iim^raTn at the ■^•mmenoement of rolunu 


NAll HAL SKr.F.CnoV 


fairly wel!.m.-irk««<l vririHtie.-*, ii»nn«ly. u' ami m' n1t•^e 

two ^ :»ri»'t'«"» will tfctUT-ll! ,• rntitiliilf to '►«• rx[i<»>»M| fo 

'.ho name <'on<litioiii which m;i(i»> t\'*"r pirfnt* vani ne, 
*nil tlie tiMiil«Mn"y lo v:»ria''il!ty i-* in itM«'U h«»n><iit.irv, 

roiix*''!'.*'!.! !•, tlii'V will ti-ti'l ♦(! ViiTT, HTI'J •:♦*'»•' »lU tO 

vary Iti ticariv iho "i,tni«> rnatinnr as th»':r jwircn'H v.iri«'(l. 
Moreovor, tht'xetwn variolios, U>irirf^o:ily ^iik'li'iv timiii- 
fird rnrm-*. \^ill t.iifl to irihtTit Ihone ailv.tiit-i;.'*'-* whwh 
.nfi<le tiii'ir [>.iri'iit ' A i rnorp numermis th.iii iim^t uf' 'he 
oth»«r inii.iliitAiit'* nt th« samp r<iiiiitpy ; th»»y will likt>- 
wi-jj* prirtikf of thii^« nupr»« j^orirral aih aiit.Vf' wliich 
ma-lf the kfciiiM tn wiiii h tin* [>.ir«>rit -i'«''i»'-i l>»M(>nL't''l, » 
lartfi^ ueiins in its (i«ii roiMitrv. A'ul thi'^n rirriini- 
jtaiifos w»< tv'iDW t(» \to fav4i!ir iiiirt to the {)rf>«iuct:oM <it 
now variftifs. 

If, thou, llu^»)f» two varioHps he vrjriaWo, th»» mo<it 
oivcrjfoiit ofthoir v.iriHtioiis will ct'nerilly ht> pr»'»<'r»tMl 
ilurui;; tlu' rioxt thoii<ci!iil krciitT'itioiis. Ami aft»r (hi^ 
intrrval, variety a' is supposed in the fliairri'n to have 
produce'! variety '/*, winch "aiU, owiijj to tlie |>ruuMjde 
of diverirt'iice, dif'»'r nior« from (A) tnan did variety a'. 
Variety m' in *iijij>oHe 1 to have prod.. I'd t*o vari»'ties, 
riarneiv m' and k-, ditferin^ troin each other, and more 
ionsidt'ra'dy from tlieir common parent (A). ^^ e may 
ontmiie t'le proi-esH hv Himiiar ste[>s tor any li"iirth of 
lime; Home lit the varietie«^, alter each Lhousa'il «;t'ner- 
atioiiH, pro<j iciny only a siinrle variftv, hot in a inore 
and more 'TKxiihed condition, ■<ome ; ro<lticini.' t**o or 
t}ir»»e ■ arit'iiex, iruJ ■jome taihriif to produce any. I hm 
the varieties or m"<lit'ied dexrendant.'*, pro<'eeding from 
the "'ommofi Marent ( A>, will trenerallv co on i;.cre.i<injf 
in numh-r and diveriTiiitr ni character. In the di.iL'ram 
the proce.-«- H rcpre-fit.d Mp to the ten-thoijw.indth 
renerat'oTi. and iinuer 'i fondensed nrui •iimniificd term 
up to the tourt •♦•ii-tiiou-vitiii'h treri^ration. 

Hut I rrui-st liere remark that 1 do not sippo*^' that 
the proce-y pv'T troe<^ on '•o re^trularly an i« repre-ient./'d 
ill liin di.'urnim, Tti(iii:.'ii m ii>«>it maii-? »«iiti»*whai 
irreirular. I am :ar from tfiinkitiif that the mo«t 
divergent varieties wili invanahiy prt'v.iiland multiply: 




a medium form rna\ r)ft(Ti Innjr oiidiirn, arul may or 
may not pnuliirp mon» tli.iii one modified dt'soeiidant ; 
for natural sele«;tion wnll always act accordintr to 
the nature of the places which are eitlier unoccuiiii-d 
or not perfectly ocruf.ied hy other hoin^rv ; and tlii-* 
Will depend on intinitejy complex relations. Hut a- 
a general rule, the more diversified i-i structure the 
(lescpfidants from any one species can he rendered, tlie 
mor*- f daces they wiii l>e enal)le<l to seize on, and the 
more tlioir modified yrnizt'ny will be in.-reased. In our 
diaLTam the line of Hucc(>sKion is hmken at retrular 
intervals hy small iiuml><T,.,i letters inarkin^.' tlie su<;- 
casive forms uhirh liav.' l>econie -ufficientiv distinct to 
he recordeil as -arielic-. Hut the'-e hreaks are im,iiri- 
nary, aii(i mii,'i.t have i.ccn in<ert<-d aMy\\), atler 
intervals loritr enoutrh tt) liave allowed the accumulation 
of a ( iinsideraide amount oi' divertrent variatidii. 

A- all the modifiotl descendant.s from a common and 
>vid»>ly-d iff used spocies. helotifing- to a larffc trenus. .vill 
tend to (r;rt;ike of the s.-inie advantaires which made 
their parent successful in life, they will ^eneralh t^o 
on muitipiyinjr in rnimhor as well as divertring in char- 
acter • this is represented in tiie <li;urram hy the several 
divprirent hrani-'ies oroceedii.r from (A;.' 'Ilic modi- 
fied off^prine from the later and more hii^hly improved 
{'ranches in the lines of descent, will, it is prohahle, 
olien take the place of, ai,d so destroy, the earlier and 
les*; improved branches : this is represented in the dn- 
sram hy some i)f the lower branches not reaching to the 
upper horizontal line*, in some cases I do not doubt 
that the process of modification will be confined to a 
Hini^le lint- of deM-ent, and the number of the .le- 
«cendanb; will not be in<-reased ; although the amount 
of divergent modification may have l)een increased in 
?iie riucccs--vt' ijen.T.iMons, Thig csis<» would he repre 
Konted III the ilijitrraju, if all the lines proccj-diiiu 
from (,\) w^re remove<l, exceptiriL' tliat from a' to *;'". 

••1 .;i^ r.-.;;:r ".ij., : : : T ;:;:.;;.<;". i.r;i' r.jTi^iInii TaOt^ iior.-'tj 

Hid Knt-'iisli pointer hav« apparently b<jth g-oiie ou 
■:*ii»nriv .hver^'iiiir in oJiaracter from their original 



stockH, WTih(»ut either having g-iveii OJf any fresh 
branchcH or races. 

After ton tliou^aiid tr^'nerations, sinvTies (A) ix -ui>- 
pMM'd to have {)r()duoe<l three toriiK, a"',/'^, and v<*", 
whirh, from haviiitj diverged in character durint: the 
puccessive )Xt?iit*nitiitns, will have come to differ larirely, 
hut perhaps urie(|iially, from each otht-r and from their 
common parent. If we suppose the amount ofchantf:e 
between each horizontal line in our dia;rram to Iw 
exces-sively <njall, these thriK? forms may still he only 
well-marke*! varieties ; or they may have arrived at the 
douhtful catetrory of suh-spe<-ie« ; hut we have only to 
8uj»|«»se thf steps in the proce*w of modifi'-ation to l>e 
more numerous or irreater in amount, to convert th»'se 
three forms into well-<letined s;»ecie,s : thus the di;Hrram 
illustrates the steps by whic'i the small ditferences 
distinifuishinc 'arieties are increased into the larj^er 
ditfereiifes di>ti'.irui.-hin;r sj>e<-ie<. Hy (ontinuintf the 
same proces.>' for a gre^iter numl)er of t'^enerations (as 
shown in the diiurram in a conden.sed and simplitied 
manner), wo ^jet eitrht si)ecies, marked by the letters 
between a'* and m'*, all descended from (A). Thus, 
as 1 believe, s[)e«'ies are n\ultiplied and t^enera are 

In a lartje jfenus it is probable that more than one 
sjKJcies would vary. in tlie diagram 1 l^ave assume<l 
tliat a second species (I) hii-s produce<l. by analotrous 
steps, after ten thousand jjeneratiens, either two well- 
marked varieties (v^" and z '^'; or two species, accordinir 
to the amount of clinuire supposed to l>e represent*,*! 
l>etween the horizontal lines. After fourteen thousiin.! 
generations, six new species, marked by the letters ;<^* 
to r'*, are suppostsl to have Insen produced. Iti e;i<-h 
^enus, the specie-;, wliicli are already extremely dif- 
ferent in character, will trenerally tend to produce the 
yre^itest numbi-r of modihexl descendants ; tor these 
will have the best chance of tillintr new and widely 
different [daces mi the polity of nature: hence in the 
diag-ram I have chosen the extreme species (A), and the 
nearly extreme species (1), as those which have lartrely 


ON IHh olllGIN OK M'h( IK.'- 

m i 



vancil, aiiii ii;ive jrivfii rise to new vari»'ties ai;d >[K»ci<»h. 
Hie other nint' -j.«-cu's (liiarkeii hy ciijii'iti ieittTy) of 
our oritiiiai ^tMiii>, may for a loiitr period continue 
to transmit una'tt-red desciMni mt- ; and this is hljown 
in thi' (JKitrrain li> the «lott»'<i lineH not pralontrt'd lar 
upwards from want of s|Kic'e. 

Hut dunii:: tiie pnK,'est >,( niodilication, n>[)rehenu5<l 
in th(> dia::rani. aiiotlier of our pri:..',i.i»'.s, namely that 
of extinction, will have playtMi an nnjhprtant part. Ai 
in e.u h fnlh stocked rountry natiirai seh-i-tion necen- 
K,iriiy acts uy ■ no heiected form ha\ine- some advanLaice 
in tlie str(iir;:u' for life over other lurms, tinTe *iil 
h«! a ruiistai.l 'endency in tht> improved d«-ie:i(lant.s ol 
an\ one specie to supfiLint and e erriiinate ui ea<'L 
sL;i-f of descent their pri-decessors and their oritfinal 
parent. lor it should he remernherod that the com- 
pel iuon will ir,.iierally i)e most severe lietv*e.-i] 
tliose forms which are most nearly related to eaii, 
other in iiahits, oinsiitiition. and stnuture. Hence 
ail the intermediate forms i.etneen tiie earlier and 
later sute,s, that i« het\*een tne less and more improve*! 
Ktate of a species, us well as the ori;final i>;uent-specie8 
itself, .vill jjenerally tend to he<ome exlmcL t>o it 
prohahly will Ikj with many whole collaU'nil linen of 
descent, winch will he cornjuered hy later and improved 
lines of de.scenL If, iiowever, the modihed otisprin^' o/ 
a sjH'cies net into some distinct country, or In-come 
quickly ada()ted to some (juite new station, iri which 
child and parent do not come into comjH»tition, hoth 
may continue to 

It then our dia^jram be ahsumed to reprc-cnt a con- 
siderahle amount of modiJication. species (A) and aij 
the earlier varieLietj will have tn'come extinct, havin*? 
heeii replaced hy eiirht nj»w spt'cie-t* (a'*t'j yn^*) \ and 
(1) will have been rephiced by 8ix (n '♦ U) z") new 

Hut we ma\ ^o further tliau this. 'llie ori)final 
8pe< les of our penus were supposed to renemUie each 
other m detrree»!, a** is so penerall) tlie c^se in 
nature ; specie.s (A) beiufi- more nearly reLiurd to li, C, 



and I), than to the other spe<'ie« ; and s|K,'ties (I) more 
toli, H, K, L, than to the others. I hese two fipei'iex 
(A) and (I), were also supjioM-d to he \ery rouinuin ano 
widely difTu^ed •[leeieH. «o that they niu-t on^'in.illy 
have had Minie adianUitfe over most of tiie other spee.eH 
of the Keiius. I heir modihed desrendanLs, fourteen in 
numiier at the f"(Hirteen-tln>ii>andth irenerntion, will 
prohahly have inht-riled some nf the same advanlayeh 
they liavp also heen niudihed and iiiij>ro\ed in h 
diversified manner at each sta^e of deseent, so a.** t<i 
have heconie adapted to many related places in the 
natural eeon<imy of their enuntry. It seems, then-lorej 
to me extremely pru!' I)le that tliey will have taken 
tlie plare:^ of, and tl. .-. exterminati d, not only their 
parents (A) and (I;, l>ut likewise some of the oriirinal 
species wliieh were most nearly related to their parents. 
Hence very few of the oritrinal spf<ies will have trans- 
mitted oifsprintr to the fourteen-thous.*indth jrenera- 
tioii. We may Sllppo^e that only one (F), of the two 
spe<ies which were clo.-.ely related to the other 
nine oritrinal species, has transmitted deiscendantH to 
thi.s late sfa;re of descent. 

The new .species in our diaa^ram descended from the 
oritrmal eleven species, will now 1h* titleen ni uijmli«r. 
()winji- to the divergent tendency of natural selection, 
the extreme amount of difference in character U*tween 
species a'* and :'* will l)e much arreater than that 
between the most different of the orijrinal eleven 
spei'ies. The new species, moreover, will l>e allied 
to each other in a widely different maimer. Of the 
eijfht descendants from (A) the three mart\ed a'*, 7'*, 
p'*, will he nearly related from haviii;: recenfJy 
branched off from ij''"; '/'* and/"'*, from havinir (ijvf ri:e«i 
at an e;irlier |>erind frum a^, will !>e in .some de^-^ree di»- 
titn"t from tlie three first-named species ; and la.stly, 
0'*, f '*, and m '♦, will \>e nearly related one to tiie other, 
but from havinj.' diverged at the hrst c«»rnmefHemetit of 
the prtH-ess of modification, will he wideiy different from 
the other five species, and may constitute a Buh jfeuus 
ur even a di.stiuct i^euug. 



The six deart'iidaiitp from (Ii will form two sulv 
jfeiicra or even ^enor.i. Hut ;ijj the ori<rin:il H|K»cie8 (I) 
ditltTi'fl lariTf'lv fnitn (A), -^taiKlini,' ne^irly at the 
extreme p »iiitfi of the oriiriiial jfeiiuh, the six (it^- 
s<!eiidants frt)m (I) will, owin^ to iiiheritan.e alone, 
dirter considerahl" from the eight (iefcendanU rroin 
(A) ; the two er<iuj»s, moreover, are HUppo^ed to have 
j^one on diveririiiff in ditierent direetious. Hie inter- 
mediate sprcies, also (and this is a very important 
consideration), whi<li connected the (tntrinal spocieti 
(A) and (1), have all l>ecome, exceptintr (F), extinct, 
an<l iiave left n(t (lt'sc»'iid;int.s. Hence the six nev 
species descended from (1), and the eitfht den-ended 
from (A), will have to be ranked as very distinct >:enera, 
or v\k'\i a8 distinct «ul>-faniilies. 

I'huH it is, as I helieve, that two or more irenera 
are produced by descent with modification, from two 
or more species of the same jjenus. And the two or 
more parent species are supposed to have descended 
from some one species of an ••arlier treiius. In our 
diagram, this is indicated by the broken lines, l»eneath 
the capital letters, converjrinK in sul>-branches down- 
wards towards a sintrle |M)int ; this point representiu^r i 
rtinf^io species, the supposed sii^fle parent of our several 
new sub-^-^enera and trenera. 

It is worth while to reflect for a moment on the 
character of the new species y '*, which is supimsed not 
to have diverj^e^l much in character, li:it to have 
retained the form of (F), either unaltered or altered 
oiilv in a slitrht deuree. In this ca-e, its atHnitie^ to 
the other fourt»'en now specie-s will be of a curiou- and 
circuitous nature. Havintr descended from a form 
wiiicli stood between the two parent -s[tecies (A) and 
(1). now supjM)sed to he extinct and uni^nown, it will ttf 
in some diirree intermediate in character between the 
tHC irroups descended from these specu-s. Hut as these 

&'•••( ?, -■--—. — .'. .11 

the ty})e of tbeir parents, the new smvies (k'*i vvill 
not lie directlv intermediate between them, but rather 
i)et«epu types of tbe two irroups ; and every naturalist 



••viil Ik? al)!e to i)rint: .'•orne such r;is« Iwrore iii- 

Ill 'hf iliatrr.iin, «>.»( h lion/ontAl line harf hilliPrto 
I I'f'ii ^uppo-fii til rt'prestMit a tiidii-am! trt«norati'>;H, luit 
♦•aril m.iv ;t'pri.>t'i.t a inilliuri or iii;i,.lrcil iiiillion 
trt'iieratioii'^, iiul Iik»-\M-t» a sortion oi the successive 
•strata of the cir'.li's crust iiiclinliiiir extinct reniauiH. 
\\ »• r*}iall, v* iicn wt« couio to our diaptcr on (ieolo^^y, 
liave to rcr-T a;.'-ain to tlii-; sul'jet't, and I think wc rhall 
then sec tliat the dia;;rani throws lij'-Jit oii the nfHiiitics 
at exlujct hciniT-, which, tluunzh jrciierally l)ch)i:;:iiiir 
to "'ic same ordt'i?., ur families, or t^'cnera, with tiiose 
nou iiviiii'', yet are often, in -onie (ie^Tee, interntediate 
in character iietween^tinj; f^mups ; and we can 
undersUuid this fact, hjr the extinct species iiveil at 
very au( epochs when the hrauchiug lines oi 

descent 1: vcfirt'd loss. 

I see nc reason to limit the [irocesf of moditication, 
as now explained, to the formation of genera alone. 
If, in our diairram, we siippo>e the amount of change 
represented hy each suices>ive trroup of divertjinj^ 
dotu'd lines to he very trreat, t!ie forms marked a '* to 
/) **, those marked '< '* and /'■*, and tho.-.e marked o " to 
m '*, will form three very distin<t t:enera. We sfiall 
also liave two very distinct f^eiiera descended from (I) ; 
and as lliese latter two t^enera, both from continued 
diverL'cnco of tharacter and from inheritance from a 
ditferent parent, vill differ widely from tlie three 
tjenera dtsceinled from (A), the two little trruups of 
4fenera will form two distinct families, or even orders, 
aecordiiiiT to tlie amount of divertrent moditication 
snp!»o^ed to he repre-eited in the d;a_'ram. And the 
tvM) new faniilie<, or nnicrs, will liave descended from 
two -pccies of t!ie orit^inal L'en-is ; and thcvc two >pcciea 
are suppo>ed lo h.i\e <ie^cended from one Hpecies of a 
still more ancient and uuknonn ^'enus. 

We liave seen that in each country it is the '•iieriea 
of the laii^er ;rencra wliich otlenest present wirietien or 
incijiient species. This, indeed, nii^rht have been 
expected ; for a*, natural selection acts through one 

11 1 


form linxiiiiT fMiiie aflv.iiiUito over otlior form? in the 
stru;:::lf lor i'.\islt>iitu', it will 'liii'lly act. on liio>-e wliicli 
Jilmnly li.ivc ?.(iiiu' aih riiita;.'c ; ;iii'l tiie I.irj^eiU'ss ot any 
(i^ruii)/ -.Ikiw^ tli.u its sjicfU's 1ih\»' iDiicritcd from a 
coMUiioii ;inr('vtiir somo .'I'lNaiit'ii,'!' in coinnion llcncj', 
the »'rii:rirl«' tor tli(» ]>ro(iijction of nt'w ami nioditied 
iic-i<'iiiiiint>. will rnainly he hotwt'cn tlii* lar:ror tfroiips, 
\\liii'li Jirt' all tryi ' to incrt'aM; in nninlier. One 
lar:i«« i^i-onp will slu s ly cuniiiicr another iar^M^ trroup, 
ri'<ii.(f it- nurnlKT-^, ami tlius If^-rn it> cliatirp of 
lurtln'r variation ,in<i im]irovenu'nt, W'itliin tlif ■<irne 
lartrt' irronp, the later and more liitfhl\ pertf<"t4>d sul>- 
jrroup^ from liranchint: out and sei/.ini: on inanv new 
]piare> in tlie polity of Nature, \\ill eon^tiintl^' tt tid to 
Mi-'pinnt anil de-troy the earlier and less improved 
sni>i:rnii!H. Snia , and hroken trroup^ and suh-t^roups 
will Ini.illy di».i|.. ar. Looking to the tutiire, we can 
J i<-dict that tl.r :.Toiip> ot' orj.Miii heintrx wlmh are 
n<iH lart'e and '.iMiinphant, and wlucli are least hrnkeri 
nji. th;;t is, ^\h!,•h as yel liave -uliereii lea-l e.vtnntion, 
will tor a liiii;.' peri((<i eimtiiii.e to increase. I4ut which 
^Tiiiips w:il uitiinately jirevail. no man can j'ledict ; 
t'nr we w.'li know tiiat man\ ^Toups, furitieriv most 
e\teu>-i\ ei\' de\elo[ied, !,,i\e no\^ Income extinct. 
I^"*k;n'_'- .still more remotely to th- future, we may 
preili. ; thai, owiiiir to the contiiuied and steady in- 
erea-e of the lander jrroiqis. a multitude ot smaller 
trruu[w wii; lieiome utterly extinit, and leave no 
ino<i,!ied dest-enilant^ ; and c'onseijuentU that ot the 
s|iec!e> livinir at any one |)eriod, extremely few will 
♦ ran-iiiii descendants to a remote futurity. 1 shall 
ha\e to re; urn to this Kuhject in the c}iaj)ter on 
(, hut I may add that on this view of 
I'xtremely tew of the more ancient spe»ies havirijf 
transmitted de-cend;int.s, and on the view of all the 
ile^ceiidaiits ot the siime species mahinti a rla>p;, we t-an 
understand how it is that there e\i>t hut \ery few 
cia-^ses HI eacii iiiiun <inision t»i liie aiiimai and \ ejf »^ 
t^ilile kin;.doms. Allhouyh extreiiud\ lew of the mo-t 
aniicut species mav imv* haw livinjr and modilie<l 



deHceiiHaiit>i, yet at the most rt'tnoto :r»>(»lot;ical period, 
the earth may have Ixjen ns w '11 ]>«'«i|)leil with many 
"Ufcies (if many trcnera, farnilit's. orders, ami, 
AS at the present 'lay. 

ISumrtuiry of ^'Kiifitt'r. ~~l{ dunns the lotitr course of 
lires ami under varyiu(f eornlitioriji uf lite, organic 
h.-inys \fiT\ at all in the several {>artfl ot their or^'aiiisa- 
tion, anil I think this cjiunot he disputed ; ir" there he, 
Dwintr t'' the hitrh t^eomctrieal ratio ot imrea.He of" each 
specie-, a severe striit^irle for lite at some aire, sea.-un, 
or year, and this certainly cann«»l Ik? di-puled ; llien, 
consideriuif the intinite complexity of tlio relations ol 
\U organic heinirs to each other and to their conditions 
ol existence, causintr an infinite diversit\- uj structure, 
constitution, and hahitjs, to he advatitatreous to them, 
1 think it would Ix* a tnost exlraunliiiaiN fa<-t if no 
variation ever had m curred useful to each heintr .■* own 
welfare, in the satne manner as so manv variations 
iuiN e occurred useful to mati. liut if \ariations useful 
to any tirL'"atiic beinir do occur, assuredly individualg 
thus ctiaracterised wiii have the best chance of Uunir 
preserve<l in the struiTi^le for life ; and fr(»m the stronjf 
iirin«uple of inheritiince they will tetid to i>rr>duce 
titf-[irinff similarly clriracterised. Tiiis principle of 
Iirf>ervati(ui, 1 have • ailed, for tlie sake of Itrevitv, 
Natural Sele<"tion; and it Iwids to the improvement of 
each creature in relation to its orjranic and inorganic 
cotiditioiis of life. 

Natural selection, on the prificiple of i^ualitia" heiiij? 
inhenlefl at correspond i lit: aL'es, can nioility tin' eir^j, 
si-eil, or youn^, as easily a-- the adult. Afiioiiirst many 
anitnals, sexual selection will trive its aid to ordinary 
selection, hy assurini,' to the most vij^nirous and !> 
adapted maU'^ ihe ^'reatest numtn'r of ofisprinj.'. Sexual 
sfiection will also (jfive characl*»rs usctii to the males 
alone, in their sirueirles with other males. 

W lietiier natural -election has naily thus acted in 
nature, in fiiodifyin^' and adaptintr the variouo form« 
of life to their ^everal conditions and st;itiou>, must bti 



judcP'I "t" l>v till' tri'iieral tenor arnl i.t t-vidcme 
^riv»Mi in tin' fMllowirij.' ••hajitcrs. IJut we .-ilroady hp»« 
li<nv it f'TitailM rxtiuction ; .iMii Imw l.irizt'lv extinrtinu 
IwH actriJ in tin' norM'^ lii^turv. .'roldtry jii.iiniv (]••- 
rlarc-i. Natunil >r'le.tioii, ;tl-<i, It- t<> <iiveri:eiioe of 
riiaracttT ; fur inort* livitiL' l^'inir* «"tii f>o swjijinrtrd ou 
t*i»' sainc rirc.i 'lit more they divorce in •itriii'*Lirf, 
haliit^, ;ui<i con-titution, of wh'ch we see i-r<'<it' *jv 
IfxikiM:; td tht' iMhal)it.'int-s of any small spot or t'> 
na' urali-eil [irndurtioii-*. i lierefore (iuriritr the nuMiirica- 
tion ot tlie 'Icsci'!! Ian*.-* ot aii\ one ^|)e<•le■<, and durin»: 
t.lie incessrint -t riit{t^le of .all 8pe«-ies to increase in 
!r:riiliers, the diMTsified the-ie descendants 
iiecome. the Itetlcr «ill be their cluiiice of hih ceedintr 
in tlie li.i'^'f ♦or life. 'I'liiis the small ditforences 
distiiiL'^ui-'liini: varieties of the Karne >i])ec!;'s. ^teadiiv 
tend to incrca-e till they come to eijiial the greater 
ditTereuces Ketwceii species of ihe same ^fentis, or ever' 
of dir-tinct trenera. 

N\'e liave seen that it is tlie common , the widely- 
ditfused, and widely-rantrintr spe<'ies, Ixdonifiiiir to the 
lartrer {fen»'ra, which varv most : and these tend to 
'ransTiiit to their modified ofTsprintr that nupenority 
whu'h now makes them dominant in their own coim- 
trie'*. Natural selection, as has just heen remarl<ed. 
kvids to divertrenco of character and to much extinction 
of the less improvetl and iiitennediate forms of life. 
< hi these principles, 1 believe, the nature of the 
■ilRnitic of ail or^'amc bein;:s may be explained. It i> 
a truly wonderful fact — the wonder of which wo are 
ant to overlook from familiarity — that all animal.s ami 
all plants *broii::hiHit all time and space siiould 1m' 
related "o e^ich other in fZT""P subordinate to jfroup, in 
rhe inai.ner which we everywhere behold — iiamelv 
>aiietie-i of the sinie species most closely reiated 
O'.'etlier. species of the same ^enun less closely aufi 
'inei.Mialh related toirether. forininir sections and sub 
j-enera, snccies of distinct genera miicli leaw closely 
related, and tretiera relattvl in ditTerent de^ree^. 
forming'' -ul>-fniiiilies, faniilios. orders. sul>-clai«e«», and 

NAT! RAL SEl.K(Tr«n' 


olas8A»s. Die spvtT.iI <iil)nrditi<'ito yrmiji- in any cIomh 
'iinnot he rankt-d in ;i sintflt' til»«, l)Ut -♦H-tii ratlifr to lie 
t lii>tere(l roiinil jtoiiil^, and tl)t'>e ruund ottuT jxtiiiLs, 
and «o nil in almost eiidlesM cycles. ( »n tlu» vi(<w that 
'-.tell sjKjcie? h:is \n'vu iiidejHMidcntly iTfatni, I can so»> 
;;o explanatinn of this jfreat fact in tlie chi-ssi;ication of 
ill organic iK'intrB ; hut, to tlie hest of my .iud;rment, it 
H exjdained throuirh iiihoritarce and the complex 
ictioii of natural nolection, eiiUtilinjf extinction an<i 
'livertjence of character, as we have seen illustrated in 
'lie dia^'rani. 

I'he atlinilies of all tlie l>einf:s of the same clans have 
■sometimes }>een represented hy a ^reat tree. I helie\e 
thi:^ wimile lar^'ely speak- tlie truth. I'he ifreen and 
'nnidin^ twijrs may renresent existing sjiecies ; and those 
jircxluced durinp cich former year may represent the 
iontr succession of extinct epe^'ies. At each peri(Ml of 
LroHtli all the prowinif twiffv liave tried to hraiicli out 
on all sides, ami to overtop and kill the surroumlirnr 
twijr^ and [(ranches, in the ^amp manner as H[>fcies and 
eroups of species hare tried to f)veriru4.sler other species 
in the jrnvit hattle for life. Hie limbs divided into 
trreat branches, ami these into lesser and lesser brnnrhes, 
«ere themselves once, when tlie tree wa.s small, huddinir 
twitrs ; and this connection of the former and pre.sent 
tiiids hy ramifyinjf hranches may well represent the 
cla^isitication of all extinct and livinj; specie- iu trroups 
suliordinate to croups. Of the many twijrs which riou- 
ri^hed when tiie tree was a mere nush, ouly tw(» or 
three, now g'rown into irreat hranches, yet iiurvi\e and 
bear all the other hrancli«^-< ; so with the species whicli 
iive<i during long-past ideological periods, \ ery few now 
bave living and modified descendants, h rom the firs; 
:^owth of the tree, many a limb and brancii havedecavt>»! 
ind dropped otf ; and these l(»st hranciies of Narioun 
sizea may represent those whole order>. families, ami 
genera which have now no living representatives, ami 
which are known to us only from having been found iu 
a fossil state. As we here and there see a thin stratr- 
t'ling branch sprintrin? from a fork low down in a tree, 



and wliich hy «i<>nm chance ha-i lieoii favoured and is 
■till alivo on itn summit, ho wf^ occasionally see an 
animal lil<t» t!n' < >riiith(irliyiichas or I/«'|)idosir»'ri, which 
in hoiiM' Kniail (Ic^-^rco cnnricctj^ by its affinitit"* two larcfl 
branches of life, and wliirh has ai>panMitly f»c>cn savtMl 
from fatal competition hy havint; inhabited a protr<t»»d 
station. As t)UiiH jjivo rs^o hv trrowth to fresh huds, and 
these, if viL'^firoiis, branch out and (nertop on all Hide** 
mariv a fct-Mer hranch, so hy feneration I helieve it 
h;u4 hepii with the t,'^roat free of Life, which tills with 
its dead and hroken branches the crust of the earth, 
and c(>\erK the surface witli ibt ever branchinjf and 
^)eauti^ui ramification'*. 



Bflf' t» "f extpnikl ,ni, t'w aU'i luu**, combliicl wllh 
iri'iiril ».l.-. ti..n ; . r^-ans "f ll.-ht aii'I f vuL.ii - Ai(.ltiiMli»»^ 
tl.ii- ('."rrflnti- n at Kr^wili < •■rTij^nimti'n ami fo..ri"niv <>t 
ur-iwth- Kalie r.irTfUlt>>ii»--MuUii.l<- ru'liiiitft.tary. hikI I wly 
,.rK.iijUr-l »tr; tur-* ^'le- I'ntU .levt I .jmM in an \ii n>.al 
nia-i'UT nr.- lil«lily varlaMf: Hf-iifl.- ( hitrsit. r» ni.ire vnnuile 
than Ketitrlc : Kvinliir) boiuhI characteni vanaMf ->i...ii» of 
thf '.iiif tf'iiin viiry HI an iit,al"»;vu» tiLiiiucr ltovfr=i ii» to 
I'Mit; I'.st 1 liaract«T« Suiuin iry. 

I HA\ K hitherto sometitnps spoken 08 if tlio vanatioiig 
— RO ciimmMU and multiform in ortranic U-iiiirs under 
.Jomofitiration, and in a looser dei.Tee in tliose in a state 
(»f nature - had l^'cn due to chainH. Hus, of course, is 
.1 wholly incorrect expression, fuit it servet* to acknow- 
ledire plainly our iifiiorance of the cause of each par- 
ticular variation. Some authors l>elie\ o it to he as much 
the function of the reproductive syntem to pro<iu.e 
individual ililterences, or very slu,'ht deviations of 
dtructure, as to make the child like ita |)arent^. I5ut 
the much greater variahility, as well as the >:reater 
fro<|ueucy of monstrosities, under domestication nr 
cultivation, than under nature, leads me to heliove 
that deviations of structure are in some way duo to llie 
nature of the cnnditi(»ns of life, to whi- li the parcntM 
and their more remote ancestors have been exposed 
.iuritu: several ;:enerations. 1 have remarked ni 'he 
rirst ciiapter — i»ut a inni; < .tliiii'iiUt- or rr.rts; -.vrijcn ;.■;;:::;;» 
he here yiven would !ie necessary to show the truth of 
tlie remark - tliat the repnHiucuve sv,,teiii is eminently 



ON T;n: oiucjin <>f ri:( iks 

Bu-M-i'iitilih' to cliaiices in tlio comlitioriH of lift- ; and to 
tlii-« •'y-t»'rii Itoititr functinri.illy (li^tlJrl•<•ll in t}ii» jirirent*, 
I rliivlly .tltriLiiti' fill" \.iryiiii: nr pl.i-tif <M»ri(lit.(iii of 
t)i'- oirspriii;:. riic iri:iU> arnl fiTii.iIr ricment"! 
sfiMii to l.(« affpctod ln'f"nn' that lin.iin taki'- plac*- wJiidi 
is ♦'• f><ru\ a now Immiic. In tlic .a-c «»f ' s|Mirtiiii: ' 
{ilants, tlio l)nil, wlii.-li in iti t»arlio<t rondition (lui-- not 
ai«|)aroiitl\ .|it!iT ••^^cntially froin .in n\iilp, i*^ alorif 
a!!fi-ti'ii I'.ut wliy, Ix'.'aijsi' flif rf|iri>()intive ny^tcni i» 
(ii-tiir!if'(i, till" or that part "IhiuM \ary more or If.v, we 
art' profoiUKily iiriiorant. N('\ prth»•l^'«i^, wo CHii lior«' 
.iM(i llifn> (liirily raN-h a faint ray ol litrht, ami we 
may feel Kiirc that there must he some caiiw for each 
(icviatioii of Ktrnctiin', lioweviT slij/ht 

Flow nnicfi (lirfct etTf.t diMcrerne of climate, food, 
etc . jiroducrJ on any heinj^^ is cxtremelv dctnhthjl. My 
■niprc— ion is, that the effect is extremely small in tlie 
I aM' <if animals, hut iierliaps ratlior more in that of 
plants. Wo may, at lea-t, safely conclude that such 
indnenres cannot liave [irodtued the manv strkint: 
an»J complex co-adaptations ot structure hptvrecn one 
oriranic hein:.'' nnd another, wliirli we >ce e\cr\ ■•( lu-re 
throinrliout nature. Some little indueinte mav i^o attri- 
buted to climate, food, etc.: thus, K. ForUis speaks 
■•oiitidently that shells at tlieir southern limit, and wlien 
livinu in sliallow water, are more hrii^litlv coh»ured than 
^ species fu 
helie\es th 
.ire more 'iritrhliy c<)loure<l under a clear atmo-^phi-re, 
ttian when livintr on islands or near the So with 
insei'ts, \\'(dlaston is convinced that residence near the 
sea affects tlieir colours. .Mixjuin- Tandon trives a ligt 
ol plants whicJi when irrowititr near the sea-shore have 
(heir leaves in some deirree fleshy, though not eNewliere 
tleshy. Several other such cases could he y^iven. 

riie fact of varieties of one species, when they raiitifl 
into the zone of liahitation of other siiecics, often 
fii tjiiir;-::;; Sii tt Very >;|;irht ue^rrce -iomo in tiif- charariefs 
vt auch nperies, accords with our view tha* species of 
al! ktuds ,»re only well-markci and pernia!!e:it vane'ien. 

those of the same snecies further north or from ifraner 
depths, (Jojild helie\es that hirds of tlie same s|K-tie8 





TTiuH the gporic- of nholln wliii h are ((iiitiued to troj>' 
aud ulialln* hvha :irc tft-iu-rnllv br>Klitrr roloure.l in 
fhoHO iftiifineil to ^•^>\^\ .iiid liwper hww. The« 
whii'i are ronfiiutl to coiititM'Tit-< arc, aconliriu' to Mr. 
irt)u!(l, hriirlitor-<'oloured llian thi>«»» of i>laij<lx I lio 
• nx«>rt-sj>ecK'>^ i-<»nfiiir<l to «t>a-( oantu, a- i-very »-olU'< tor 
knows, are otteii hransy or i.riil. I'lantj4 whii-h live 
♦•xilimivolv on the sca-'«i<le an- v^ry H|>t '<• liav(< tli'-h? 
leaves. lie i< tio believes in the i reatinri ot earh 
^jMM ie«, will ha\e t<' ^^ay that this sliell, for iiislaine. 
wa- create«l with l>rii.'ht colours for a warm •«' i , 
hut that this other shell heeanie liri^'ht-coloured hy 
variation when it rauKe*' >'>to warnier or shallower 

N\ heu a variation is of the sliirhtest u*e to a lieititf, 
we eanrsot tell how mueh of it to attribute to the a«»;u- 
rmilativp action of natural Mjh'ctiDii, and how much to 
the conditions of life. 'I'hu", it is well known to fur- 
riers that animals of the sijine s|)e< ie'^ have thicker and 
better fur the more severe the climate is under wiiicii 
tlitu' have lived ; hut who can tell how much of tin* 
ditferente may he due lo the warmest-clad individual-t 
havingr been favoured and preserved durintr nany 
:;e:.erit'ons. and how much to the direct action of 
the severe climate.' for it won!! app'-ir that clirr.ate 
lirvs Bome direct action ou the hair of our doiru;.-it:i" 

Instances could be iriven of the s-ame variety beiiu' 
pr«»<iuced under conditions of life as different as can 
well 1)6 conceive<l ; and, on the other hand, of ditferent 
varieties 1km n^r pro«Iuced from the same sj»e«'es under 
ihe same conditions. Such fact> show how iiidiro<-tl. 
the conditions of life act Again, innumerable instances 
are known to every naturalist of sj>ecic8 keepintr true, 
or not varying at all, althouirh livinjr under the mopt 
opposite climates. Such considerations as these incline 
me to lay very little weight on the direct action of the 
•ondilions of life. iu<iireciiy, as aireadv ieiiia?Ke«i, 
the" seem to plav an imjuirtiinl [lart in atfectnitr the 
re;'ruductive aysteni, and in thus induiing variability ; 



.4'!ii ri.i'iirrt! -flection will tlion •irciirrmiatc all [)r<ifitAi>le 
vrinat c>ii>. ".v.vt'r "-li^'ht. until they IxH-omo plaiiilv 
(ievcloj f(l iiM I apfiriM'iaMt; \>y 'n*. 

tlif^'ts fif I'y mid lhx\iiif. — i''rnni 'lie fn.r\^ alliiiicd tn 
ifj the tirst ciiafifcr. I think thfre can Ik' litt lo lioiih! 
that use in ntir fionMwtic aniinai-; ^t rpntrtli«iis an-l vw 
lartres certaiii ii.irt.>J, ami 'lisu-^c dinii'ii^lit's thorn ; ani 
that suctt mo«lificati<in.-i aro iiiln'ri'i'ii. I'mitT trt'o 

■ 'nre, wo can have no htaiulard vl ''uiiiii,ir-"n. hy 
I .' h to jmlirt* i)f' the etTects nl' 'onij-roiitiniu'ii use i-r 

di'...; e, tor vve ktiuw not the pamnt fe-rii-: ; hut many 
.». •m'!.! have structure-; which can '••• explainei! }>y the 

■ 'ects ot i!:«.nse. A-< Prnfes'-or' '.vcis h;!> re'iLirki-d, t.liere 
in no ert^ater anomaly in Tiature than a hird tliat cannot 
fly ; yet there are several in tins sta'e. I he loiTL'tT- 
hendeil duck of South America can only flap alontr ;he 
BurfVtce ot" the wati-r. anil iias it-; \viii^--< in nearly the 
same coniiilKii a- the donu'situ: Avle-hury duck. A^. tlie 
lar^rer irrounii-fetMiuiL' hirds hi-Mcui t;ike r'.i^ht except t<^i 
es<-af e d:Mi:,'er, I nehevo that the ni'arly winL'le>s condi- 
tion 'It' Ke\er-ii hirds. hIui h 'ow inliahit or lia%'e late!;, 
inliai'ited -e\eril oce.anic i-^land-i. tenanted hv no h -a-. 
ot" pri'\', lias (■een caused hy di-^u.-e. Tlie o-tncli indeeu 
iuhahits continents and is exposed to da'ii.'-er from which 
it cannot escape hv fliirbl, hut hv kicking' it can (leiend 
itself" Horn en«'mies, ax well as any ot" the >tnailer ijuad- 
rujH'tls We r'ia\- iniaj-uu' that the early protrenitor 
of ttie ostrii'h luid liabits like tho--e of a hustard, and 
that as iiatural selectioi; iiicroased in jjuccessive trenera- 
tions the si/»> and weiyht of its hodv, its le^'s were u»ed 
more, aiid its wiiej-s less, until t!i«'y liecame incapahle 
of liiirht. 

Kirhv has remarked (and I ha' e ohserved the same 
^act) that t.'io anter'or tarsi, ot feet, of' many male 
duTiiT- feeding bt^etles are very ot\eii broken utf; he 
exarnined sevetiteen specimens m his nwn cidlertion, 
%;.<: ;;iii .r;f ii ir; eve:; r» rv\.v ;e:;.. ;:; : :;• \ •-.iwir^ 

fcpelles the Uirsi nre so hahitu-llv lost, that Mie insect 
h.iS hi en desiuilied e.s fml haviHiC th-'ru. In swme 



othor ?ei.era tlu-y .ire present, tint ".\ a rti<iimotitary 
LOMtlition. Ill tlip Att'iu-iiiM or aacrtnl ln'otle of the 
Ku'Vptian-j, tln'V aio totally <h-!'u-ient. itiore is not 
suificuMil *•'. iiit'iiCt! to iniluce nie tn Ix'lieve that miitila- 
tiOMH art) OMT iiiiicrit»'(i ; and I -liu'ild pnMrr pxpiain 
uiji 'Jip t'fitiry ali-enco of iho anter Or l:ir-'i in Atcuchus, 
arid their nulinu-isUiry cdiniition in some other irfiu'ra, 
bv the lonir-cont:iiiie«i eiit-cts of ilisuxo m thoir pro- 
t'pnitora ; tnr as the tarsi aro almost always lost in 
rnanv iii;tii_'"-f*M"ii:itr lK'»'tlps. tliey uri-t li<> 1 )-it early in 
liff. and thereloro fatinui i»e much n<M !>y liiese 

In suiiie rases w-e uu^'ht cn'^Ily put dnwn to disuse 

riin.liiications of structure which are '.vhnily, or mainly, 

due tn natural M'lei tiou. Mr. \\'olI.i-:ton di-cosered 

the remarkahle fact that -J'hi's. on. of the .'>M 

■species ;!ih;i*-itinir Ma>li'ira. are so far dfficu'iit in 

wii';L'S that they cannot fly ; and that of the twftity- 

nine endemic {,'erier.i, no less than twenty-lhr'H- ir'-nera 

have all their -iperjc- in tliis conditio,! '. Se\eral lacts, 

namelv, thil heothvs in many f.arts of liie world are 

fre-juently idonn to sea and perish ; thai the beetles 

iu Maleini, av oi'-erved hy Mr. W'olliston, lie much 

coie-ealed, until the wnid lulirt and tlie sun shines; 

that tlie proportion ot winj,^lesH heet!e«i :s lar-'er on 

the exposed l>eserta.s than in Maiieira iu^elf ; and 

eH|KH'ialiv the extraordinary fact, to strontriy insisted 

on tiy Mr. W ollaston, of the almost entire atisence of 

certain lari." trroiips of U'-'tles, elscwliere excessively 

tiiimerous, ;tnd vstuch groups liave hahiUs of lite almoat 

neeessitatiiitr fre«iuent I'uu'ht; -these several considera- 

'.ions have made me heln ve that the wuJtrless coiidition 

of so many .Madeira beetles is manily liue ro tli*' action 

if !iatural st>iecnon, but combined proba'iiy with dis- 

ise. t or durinjr tiiou-.mds of sucie.->si\e generations 

-ach ii:.ii\idual iieetlo which i:ew least, either from ita 

ha\!n;r iKfen ever so littU- le.sH jM»rfectly de- 


> t'il 'i'^'O » »l i J Kill I ! Hl> ' •- HL If* .'* ty "^ I4» ■ 'tl •'* ...*- "^- * 

■'hame ot survivin.: frimi not bfiin; bhwii out to ^ea ; 
an.i. on the other "ti.ind, those '.K-eUes wh,ch luoui 




r».i<li!y toitk to fli^iit would (ifUMic.-t liavc iifoii hlo\rn 
to -o.'i and thus hnvc liopii <!^'str()ve<l. 

I }i»* itisoct-j in Madeira whi< h .-ire not i.Tir..ii>i-ft'edor8, 
.trxi vvliirli. a" Hjp fiower-tVcliii:.'- coh'oj.trra a:id Ippi- 
dotitcr.i, rnust Ji.iliit'ially ii^f !hp;r wiiiif'; to eraiti 'heir 
fluii-iftenc*', have, as Sir. Wjillasfon •<uj-i>«H-t-. 'lifir 
wiriiT'' H'lt at all rodurt'd, liut oven onlartred. Hii- :n 
ijiiit-' t'(ii!i].atil)lp witli tlif action of natural -.ploctinn. 
For whiM) a now in^.'ct tirKt. arrived on tl.c :-..ini;. the 
t.jmierii V ot natural "^(dectiou to Piilartrc or !o r«'diii-e 
th»' wu',:.*--:, uould dcjiciid oil w lift hrr a trrpater mimher 
of indiid.iah wo-c s.ivt'ii by nuccessfulK hnttlin;.'^ with 
tlio winds, or by invinir up tho attempt and rartdv or 
iievtT living;. A-* witli mar;npr« shipwrockfr! near a 
coast, it would liivp l)eon hcttfr for tin* ^'■ood f.v ;Tiini<-rs 
if th;'v li.'id hpon ahin to ^".vinl still hirtlit'r, wlitTca- it 
wo, .Id liavp IxMMi Ix'ttor for the had swirumo.-- :f tlu'V 
had not been ablo to swim at all and Lad stuck to the 

I'he cyef^ of moles and of somo burrowinL' rodents 
are rudimontary in ni^e, and in some cases cjuite 
covered up by skin and fur. This state of the eyps in 
p.-oliahly due to trradual reduction from iisuse, but 
aided perh.ips by natural selection. In South America, 
a luirrowiriiT rodeiit, tho tuco-tuco, or ( U'nomvs. is 
even more subterranean in iti- haliits than the mole ; 
and I was assured by a Spaniard, who had often c.iuet.t 
them, that they were freijuently blind ; one wh:< h I 
Kept ai;\r- was certainly in this t-oiuiition, the cause, 
as ap|ieared on dissection, liaving: been intiammation of 
the inctitatintr membrane. As fro.juent intbmmatiou 
of tlie eye.s he injurious to any animal, and a*, 
eyes are certainly not indispensable to animal.H with 
^l.htermneAn habitjj, a reduction in tlieir size witli 
the adhei»ion of the eye-lids and trrowth of fur over 
them, miirht in such ra-se be an advantage ; and if so, 
natural seJection would con.<itaiitly aid the etfectn of 

It is well known tiiat several animals, belonerintf to 
the most different dasse", which inhabit the cave** of 



Styria .ind of Kfiitiirky, an- ' ,'1. In fomr of the 
c.TAhn the foot- stalk for the »>yp r.-nviiiKs, thouijh the 
♦•ye i" tT'Hie ; the stiiid for the te!e><*<)pe is there, 
tiioiiirh thf t»'le,<i'ope with i*- j-iitsses li;i.>« Wen h)>Jt. 
A-: it !■» (liMiiult to ini.-itriTie tint eyes, thoiiirli u^ele^', 
rould he iii .inv \\;iy iniurioii!* to .'iinmals liv-ncr in 
darkiies.-s, I .itiribiite their lo.« wholly to livuse. lu 
o!ie of the Mind anim.ils, li.imeiy, tin- cave-rat. the 
evos are of immense ^i/.e : and Profes->or >illin>an 
thoiia^lit that it retrained, after livintr ><onu' d.iv- in 
the liirlit, some 'sii:,'ht jiowcr of vision. hi ;he ■-aine 
iiiHiincr .xs in Madeira the uuiirs of some of the in*.e<t.«. 
have h«x*n enlart'ed, and tlie wintrs of other- !ia\e iuen 
re<liiced hv natural selection aided hy use and di> i^e. 
so in the case of the cave- rat natiira! st'h-. tioii seems to 
have 3truci:lod with the loss of iiirht and to liave in- 
creased the size of the eyes ; wherens witli all the 
other inhahitants of the caven, disune by itself weeriis to 
have done it.n work. 

It is difficult to imairine condition** of life more 
similar than deep linie-tfine cavern- under a nearly 
similar climate; so that on the common view of ilu- 
blind animals havinir l)een separately created for the 
American and Kurope^n caverns, close similarity in 
thc'r orji'ani.satioii and aiRnities mitrht ha-.t- tieen ex- 
pected ; liut, as Schiodte and others have remarked, 
this is not the case, and the cave-insects of the two 
continental are not more closely allied than mijrht have 
hecti anticipated from the i.'-eneral'mhlance of the 
other inhabitants of North .\merica and K.urope. ( )n 
trv view we nnist suppose that Anicrican animals, 
havinjr ordinary powers ot visi(»n, slowly mitfrate.j by 
fiuc(<'ssive ireneratioiit; from tlie outer world into the 
deeper and deeper recesses of tlie Kentucky cave-, a." 
did Kuropean animai.s into the caves of Kuro[.e. We 
liave some evidence of this irradation of iiabit ; for, 
a.s Schiodte remarks, 'animals not far remote from 
ordinary forms, jirepare the transition trorii iitrlit to 
darkness. Next follow those that an' con.structc(! for 
twiliirht; and, l.-utt of all, tliosc destines! for total dark- 




iiess.' |}\ llif time an liad rcicliod, atler 
nuMilu-rlessi ir''fH'!nns, tlic dci'j>t'-t ^('<•c^s«•s, clHuse 
will oil tliis view h.ivti nmro nr ic><* p<»rft'ctly oliiitei- 
at«'(i it> oves, ami rutural «.»'lfcli(.ii wiil «»fU'n have 
«'lK''ti'(l otliiT cli.mijt'-, smli a> ai iTicrc.-ise in the 
l»?u;jlli of tlio aiit.MiriH' or ['.ilpi, a- a <'oii!j»('iiK,-i!ioii 
for itiitnii'-i-.. Notu ilhst.-iii(iinir surh niomticatiori,-, 
w»' tmclit cxfK'ct stiil to >-,■(» in -h,. en .'-animals of 
AriuTica. atrniiti(<>- to lin- otiu-r iiiii,ili.taiit>- of that 
ci'T,. iiiMl.aiid 111 tiiosfc u; hiHii[ii', lo tht' ii.hainiaiiL>» 
of tie Kurnj.faii < oiititient. Ana tli.-i i^ the la^i- with 
NotiM' of tlj«' Aiii. ■■I'Mii cavt'-aiiiiiial ■. a- I I . ,i- from 
I*rn;c-.^(ir I >ana : ri;;ii Mime oi tlu' I'iun.;,, ,u i .-tNO 
in-i'i-; .in* v«'rv (1.1-..'!^ allied t<i tlinsc oi tlic - .rrriuud 
lur ('"'iiitry. It \M, ilil \>f TitoNt liiiiiiuli t<i i:\\v anv 
rational expliiatioii ot thf altinitifs of ihe i)li;i.l ravt^ 
animal- to tlit- other luiialiitaiits of lin; tuii contiiicntf 
on tiic oniiii.iry vi«'W ot tiioir indijiciidiMit crcafion 
Thai -rvc ill (i! tiiP iuhaliiuiii'- of luv r:>.\i^s ot tli«' ( »id 
and N'i'W W orhN ^lioiild Im (•lo-><'iv ndatt'd. we ii. j!ii 
«^\]i'i: irorn tl,c wtdl - ktiowii rtdatioiisl.i ji of mi,-,i of 
ihi'ir otinT |irodurtiitiis. lar tiom fjMdiii:: ara >ur 
pri-»' thai >omi' ot the <a\«>- animals -houid ho very 
anoiiiaioiis, i- Atri-si/, ha^ ri-markfii ;n r«'L'ard to the 
hlinii ti-li. tin- Aiird V u|'-i-, and a- is the ca-r v\itii ilu- 
hli' d l''ii:«'ii.- U;!h rcfcrt'.i.i' to the n-ptih'* of l-.iiroiie, 
I a'li only surpri.-ed that iiioir wrerkv of ancifiit life 
have not In'en preserved, owiuu: i" Mh- Ic^* -. . i-rc 
pi'ti'ii.ii to wiiiidi the iiihaiiil;i!;t> ot tia'^t' U iri'. al'odc> 
will prolialdy ha\ ,- hi't-i! vxpo-ed. 

A'l-ti'inriX'i'uii,. iiahit i> hi'r»'oi;ary \\ itli [daiits. a? 
in 'iic peruul o' lioweriu;:, in liir :imoi,nt of rain 
reijuiviti- lor r><-i-d- to t;t'riinnatt', iii ihf time of -Ict'p. 
etc., and ihi.s nails me to sa\ a h'v\ word^ on atciima- As it i^ fxtronudv i-ommon tor ^p<•< i«.s ot tlie 
HAiim i^ontiB til inii.'ilist \imv i iit and ii'r\ told count rio.. 
and a> ! ludieNC that all the >pecu'«. <ii the same ccnus 
have di'M'i-nded irom a ^iiiiile parent, if th - view be 
corn-il, acclimatis;ition mtiKl i»e re.idiiv eiieiU'd dariujr 



l(>nfr-coiitiiiUf(l (ic^coiit. It i^J JHitnriuis tlwit r.icli 

fjHJcies i-; .'ni.iptt'il Ut tlie i-lirtiate ot ;t< i>wn Ikmim' 

»pe«'ies (Vi'iii at, .iniir or even Iroiii a t<':nj'<'r;.t<' reiriou 

I'.aiiiuit euMiirt" -i trojiical clitiiatt', (tr oou\t'r-f!\ . Si> 

aca;!!, niiiiy siKcuU'iit jii.'int?< caiUKit einiur*' a <i.iin|> 

rliiii.ili!. llui ilu' (it i.'ri't' ol aiiapLiliuii i)t ^jn-cn'-. Im 

'.lit* ('litiKil>'>i iiinicr « Inch tin*} liv«' i« <itti-i! ovorrati"!. 

\\ r t:ia\ i;ii«'r Uiis irom our ii <'<jiifiit iuai'ilitv to ]<:' 

• iiri 'Aiii-ilifr or i.nt aii irii|.ort«'(i j.iant wili einiurt- our 

I'liiiiatf. aii'l irmr. tii»- iiuiiiiicr «>t |>i.\rit» a!:ii ;iiiirnal.i 

tiroiitht Iri'iii waiiiuT couutru*? wliuii Iutc f!iii>\ troo'i 

licailli. \\ »> l.a\f r»M-oii to ItclitMi' Inat ^pi-. u-- \u > 

ffUiU' of nature an- iiitiilru iij tdrir raMirt'>' tiv the roni- 

p.'f.tioM of otliiT umaiiic lt«iiiirs (juitc a.- iiuu-h as, n; 

iiion- than, hy ail.ipJaliori to jiartii' I'li.'iiati's. Iliil 

\'. ht'tin T or ii'H tilt" achiptalioii In* L'lMitTiilh vi-iy rlosi- 
. : ;.i ... . . ■ . .,i' . . 

tln'ir l)ec(iiii'.ii' 

. Ill tiu' ca.-t o; -'iiu.' lev* phijit.-. 

-. _. to a ciTtain exti'Jil. hahiti; 

ate<i to ililit-n-iit t'Tripfnitiirt'^, or hi'< nrni!i_' ai'i'liriia- 
ti-»'(i : thu.» thf [liiii-.- ami riiodociiiiuron;*, rist-ii iVi' 
-ml «'r)lh'rli'ii hy I»r. Hooker Iroiii trt'**.-' irrnvv ii^' ai 
ijilicrtut iifii' 'itH on thf 1 lunala\a, «iTf> toumi in tlii.s 
I 'jntij to j>ossf-.>- tlitiiTt'nt roiistitiiiionai poHtT?" of 
r«'*i>linir cnhl. Mr. Mun ail*.'-, iiito.'-iii- ine 'hat he fias 
oi»er\(-(l >«iniiiai tart- in ( cvhin. aiut ai.i.o.cpi^ nh^rr 
\alioi,v h;>\e fn't-n riiailo hv .Mr. 11. ( . W at-on on 
Liirnjic.iii sjitTu") of jiLaiil-x liroutrht from thi* A/orp- 
!o Ln^laiul. In rt'i.Mrti lo anunai-. .■.t">'frai niithentii- 
i-a-'cs ,;oui<i lit' fiiviM of .<]>t't"u'* VMihiii hl^to^ll•al tune"' 
tiaviiiir larufly cxtendeii itieii rant.'f from wariiit-r to 
i:t»<ih'r latitu(ii'>, an'l con\('r*oly ; iuit we <!o not j.o-i- 
tiveiy know lliat tlit'se animal.-. \vt'n> -.trii Uy h<1.ij.u«1 
to lhc;r native cliiiat*', l)ij; m all irnlmary ca-.'^ \m' 
a.'^sunie such to !ie tiie ; nor lio we kno« thev 
ha\e suhseijiHMiliy hetoiiie a<."Ciimali-e<l lo thi-u iit-w 

A.>i 1 iielio^e that our tioinestic animal-' were orijin- 
ail'. cho>-«Mi l>v linen iiiMit man In-tau-e tiiev we.i-e 
li-efijl and hreti reaiiil) under confinement, an<i n.>l 
because itiey «ire ^i.bse.jueutly lourui ca]>ihi. .f 




extciKlctl trari>;,i»rt.ilin:i, ! think th<' rominou arui 
extraoriliri.iry <njiru"ity iii lur iiMni«?^tir aniinrils oi 
ii.)t OTily;iiriLr *'in' mo^f ditiert'iit <;«'>; lnit 
of beiiiL' }Mrk'ttly tortile (n far -everor t«'st) umlrr 
thorn, iiiav ^f 'iscil as riii ari,'!iTnf'!if t!i;it a l;i!;,''e pri>- 
-)orti«)n of «;th»>r anim il>, riuw in a fctatr of ii.ii iro, 
' oiild easily l»« tiroUizlit to U-ar si'U'Iy dit^'tTout 
rlimatos. We Tiin>t not, bo.vrwr, jui-h !}ip Min>- 
^niii^r ari^^uiut'iit too tar, on account ot the [iroii;il);i' 
orii:in (it ■jdiik! <if ftiir lionu'stic aninMl< from Ke\eral 
••villi storks : tin' Mood, t'or in^, < : i t:ojiical and 
arctic wolf or wild d"ir iii?.y piThrtji- !>e wnnuflrd in 
our dotju'st'r lirci'ds. I lie rat aiid :iiou-<' laininf Ki> 
ro!isidert'i! as dniii-'- ■ ic iTiitnal-. (nil thry h.i\<> i)t'i'n 
tri.n^jMirted by man to .n:t;iy pait- of tin' wurid, ai'd 
n"W li:\ve a far v^idrr -iii^-e tlian ai y mhrr rodoiit, 
living fr»'o under flic <"o!d cliniatc of Karoe in the 
ncr 'ii ani.i ot tin* Kalklaiuls in thf -outh. and o.n many 
isjanils \u tlio torrid zoni's. llcnr'' I an\ inrLni'ii to 
look at adaptation to any special ijimato as a ijuality 
readilv u:r;iftt'd on an innHtc wide ncvr.iiity of (•on^ti- 
tutioii, whii !' is common to n,o~t inimaU. ( )n tin;! 
V it'~", thi- .•;i])a('ity of fidurinji the most ditfere!;t 
tlimatos t>\ man himself and hy his domestic animals, 
aii<! sucli fai'ts .is that former Epecies of tho elepliant 
and rhinoceros were c;!paidc of endiiiny a tjlacial 
cliinafe. 's iMTcas tiie liviii;f si>eCit-^ are i ov all tr"p:ca' 
f,r siih-trojiical in their hatiits, ()uy:ht not to he looked 
at as anonialiiv-, Imt meroiy as examples of a very 
omnion rlo.Mi»ilitv of constitution, brouirht, under 
peculiar !irciimstanc«'S, into play. 

How much ot the acciimai isatioii of Ppecits to any 
peculi.if vlimate is due to mere liahit, and iiow much t<» 
tho isatural selection f>f var'et;o- havin.r dj*'crent iiin'-.'e 
.•(instituli'Mis. and liow much to both main.- cimiltiiitil. 
i« i 'prv oltscurc i|uestion. I'liat hai>/ or custom ha- 
some inlluence I nuist believe, both fr un analoiry, ard 
ironi the inco>-vknt advice trivn m arricuitural work.-. 
«>ven in tlie ancient Eni-yclop::'iii;is of ( hina, to be very 
caulioiis in trau^posin^ aniuiais f'-om one d>trict t^"' 



.mother; tor it i.« ;i<»t Iik<'ly that iii.iii slioijld have mir 
Cffiled in seltM-ting: ho many hr»'e<N find sut^-hr»M>d^ with 
<M>:i->titutioiis specially titted fo.- tlicir i»wn districts : 
tlie result rnuiit. I think, be due to iialiit, < »ii tiie otli«'r 
hand, I can see no reason tmloiiht that natural selntioii 
w ill contuiualiy tend t<» procrvr tlnc^e individuaU vtliich 
are horn with constitutions he-t adapted to their natun 
countries. In treatises on many kinds of ciiltivatfil 
plants, certain varieties are said to<i certain 
ciiinates hettcr than others : this is vcrv -trikin::lv 
own in works on trnit tree* puhli^hfcj in' the I'nited 
>t'ites, in wtiirh (frtain varieties are hat-iiiiallv re. om- 
mendt'd h»r tlie northern, and others tor tiie soutliern 
States; and as most of these varieties are of recent 
oriiTin, they cannot owe their coti-titiitionaj iIilFcrences 
tohahit. I he cp.-j' of the .Icrii-.aleni artichoke, which 
is nev»!r propa;:alfil hy scoi, .inil (»f which « <iti-.»-,j;,,iitU 
new varieties have not heeii produced, has even heeii 
advanced tor it is now as tt-nder as ever it w.i^ .is 
proviiiif tliat acclimati-.ition ciniiot I .• ,.t••^.,•tcd ! The 
case.als(». of tlie kidney-hean has heen otten cited for a 
similar purpose, and 'Aitii min-h irreater weiirht ; hut 
until some (»ne will sow. durinir a score of L-'einration.-. 
his kidiiey-heans so early that :t ver\ lar_i« i>roportion 

are destroyed t-y frost, and then colle.t ,i trom tlie 

few survivors, with care to prevent a<-ci(!enf.i! cro-ses, 
and then attain t'et seed troin the-e seedlin^rs, with the 
s.'ime pre<aiiti(uis, the exjieriment cannot lie saiil to 
have heen even tried. Nor h-t it he -uppo-ed tliat no 
liilfereiices i". the con>.titiition of seedliiu: ki>inev-he;in!^ 
ever npjicar. for an account has heen puhji^lied how 
much more tiardy some seedlinirs appeared to ho than 

On the whole, I tlaiik we mav conclude hahit. 
Use. and (ii^use, iia\e. in some ca>es, played a consider- 
ahle jiart in the moditication of the constitution, atid 
ot the structure of variou> or^'ans ; hut the effci-ti 
oi use and tiisusc have often t.een lartjeiv c«»nihine<i 
with, and sometime.s overmastered hy tlie nature] 
selection of innate varialiona. 



Ciirrrlntiou ot dnnrth. I nu'.iTi hy tliin »'xy»res«ij>n 
tli;it the wliul«' <irt:;iiii->atii>M ix m> tied* totrr'tlxT (lurinjr 
itsLTowtli ami (l('V('li>|)ii,fiit. that « li«'ii rili^rlit v,-iri.itioii« 
ill ;iiiv on«' j»irt occur, ami arc accunuilatcil throujrh 
li.'itiiral .sflt'ctidii. oth'T |iar'» Ix'cotiio rii'Ml'tii'ii. I hi- i<» 
;i \('ry iin|i<irtaiit Mihj<*ct, nio-t ini|n«rtt'ctly uinliT-tO'xl. 
The riKi'^t (iliviiiiis ca>»' i-. that moililicatious accumiihitefl 
«4(ilcls' for till' trooil of the yomiir or iarva, will, it may 
Kati'ly he ••oiicliidcd. a:i»'ct the structurt' «)f the adult ; 
in tlie same niaiiiier as aiiv Mialcoiilnriiiatioii affectin^r 
tin'! early «'iiiltr\(), f;erii»ii'«lv atfi'cL>* the whole or^/aiiisa- 
lioM of the aiiiiit. ihe ve\«'ral parts of t tie hody which 
are lioino!o;rous. ami whicii. ;it an eariy erntiryouie 
period, are alike, seem liahle t(t vary in an allii'd ni.umer: 
v.e see thi^ in the r:_ht and h't> -i<ies ot the hodv ^aryini; 
in the same tniiiiner ; in the front .md li;nd lej>. antl 
evt-n in tlie \:k\\^ anil liiiih-. xarvinir tii:_'e'her. i^r the 
lovver jaw is helieved "o he hnmolotrons with the hmh-.. 
I'hf-e tendencies. I do not douht, niav he ma'«tered 
more or less com|'!et(dy hv natural s>de<tiiin : thus a 
familv of NtaL'"s once exivtcil with an antler only on one 
^itle ; and it thi- had Im-cii of any ::reat use tothe hreed 
it mi^ht jtrohahlv hav,' hem rendered permanent hy 
nat iiral ^election. 

1 lomohiirou- parts, ;i.s has heen remarked hy sotii*^ 
author-", tend to cohere; this is ofteii ^een in monstrous 
plant>; and nothin:r i- more common tiian the union of 
)iom«>lo::ous parts in normal structures, as the union of 
the |M'tals of the corolla into a tuhe. Hard parts -eem 
to atiect the form of idionnnir soft part- ; it is helieved 
hy ooiiu' authors that the di\ersity in the shape of the 
pel\i> in hirds cau~e* the retnarkahle diversity in the 
shape of their kidne\-. ()thers iiehe\e that the sliape 
of the pehis iti the human mother it tluem-es hy pres- 
sure the •'liape of the head of the ciidd. In snakes, 
accord. nj- to >(hle::el. the shape o: tlu' holy and the 
maimer of sw.iHowintr dete;-mi:;e t!.e position of >e\eral 
ot the mo»t imjtortant vix-era. 

The nature of the lioiid of eorrelation is very trft- 
quently .]uite ohscure. M. Is. (ieottroy >t. Ililaire hM> 



fnrcihly remarkcil, tliat cert.-im inaI<oiifi>rir.itinri>* wry 
frequently, and t)iat others rarely rcx'xi-it, without our 
hoiiitr ahU' to ^'^it.'n aiiv r«»a><i:. \V hat i-aii \>i' niorp 
singular than t,i*';on ht'tw»-«vi iilijc cyc' imi 
iieNj" in cats, and the tort(ii-;r-.h«^ll .nhiiir with tlu- Irtnalt, 
■;«'x : the feathfrt'd fret an<i >kin h«'t.w,.t«ii th«' out»'r t«M«H 
in piiT^'on-*, and thf |ir»>~«'n(«' ot" more or ii's-; down on 
tlie \ouiiir hirds whi'ii fir>t hatrht'd, wit)i tlu' futurf 
r<doiir ot'thnr {duniii^-t' ; or. a::;iiii. the r«latioii h«'tween 
the hair and tertli in the nake<l I urki-li do::, ttion^'h 
liere prohatdy hoiiu)h»iry coni*'-" into jday ' W ilh 
re-pett to thi- latter ca^e ot (-(trrelation, 1 tinnk it <an 
hardly he arciilental, tliat if we pirk out the two orders 
of niainnialia which are n)'i>l .ilinorniai in tlielr dciTiial 
covfrinif. viz. ( t-tacea (whah's) and l-dent.ita arriia- 
dilloei, scaly ant-caters, etc. ), tliat the-e are likewi>e 
the nio«t ahiiorinal in their tectl:. 

1 know ot" no case hetter ada{)ted to ^hov* tiie iin- 
port.mce of the l.uvs of correlation in iiiodKyititr nn- 
port^mt structure-, indepeiideiitlv of" utility ami, t^ier*- 
f'lre. of n.itural seh-ctiuii, 'h.m that of tlie dirh-niiro 
hetween the <iiiter anrl intn-r flowers in some < ninpo- 
sitous and I inhellit'tTou* plants. Kvcryone know'^ tiie 
difference in the ray and central florets of, for instance, 
the daisv,and this difference is often ed with 
llie ahortion of part- of the flower. Kiit, in r.ome ( om- 
povitous plants, the se.-ds also differ in -h.ipe .tiid 
sculpture ; ami evii the o\,iry it-elf, wit! ^■' ac«'e— nry 
p.-irts, differs, as lias het-n de-crilietl hy ( a- -mi. i'iicse 
differences have heen attnlnitcd hy some authors to 
pressure, and the shape of the -et'ds in the ray-tloret.s 
in -onie ( omposita* cou»itciian<es this idea ; hut, in the of the corolla of the ' ml.eilif"era', it i> hy no mean-, 
as l)r. Hooker informs me, in species with the den-est 
head;, that the inner and outer flowers most freijuenlly 
differ. It mi^rlit have heen thou^rht that the development 
of tlie rav-nefals hv draw in;.' nouri-hment from i-ertain 
other parts of the flower had cau-ed their ahortion ; 
hut in >i(ime ( omjM»sit;e t u«'i o is a difference in the -eeds 
of the outer and inner floret- w thoiit any difference in 

\ '■ 




t)i»' foroll.i. l*os>iMy, these d ff»'ri'ines niiy he 
cniiiit'ctc'l witli somo difrpmirp in tho tlmv nf nitri 
meiit tovririln tlu> cciifiMl .irnl f>\t«>rii.kl d'lwrr'- ■ «») 
know, at ltM->t, tii.iii 111 irri'L'ular llnncrs, tliu-** iitMr«'-.t 
to tlio ;ixi-i .irn o(tfrH»<l suliji'ct 'n [n'lnri'i, ami ln'criiiio 
roL'iil'ir. I inav miii. ri'^ an Mi-t.iin'<> ot t)iix, atnl nf :i 
•itriUiiiir iTise (if nirrrl.itioti, I have recently ob- 
-I'fNiil m >i<irjii> iT'irdeii pi-lrir^'iiiiiiiiii-. tliat the cj-iitral 
llower of the tni-<-< often Nwcs the p.itchex of <lark«'r 
rulitiir in th'» two iipiier fn-taU , :i:iil that when this 
(n iiir-, th»> adherent in'ctiiry )■* ijuite a'nirtcd ; w}ieu 
tho foh)iir i'^ ah«ent frnT)i <»nly one of tlie two upper 
pctaN. the ueefary i-i only jtiu<1i shortened. 

^^'ith re-p»'ct to tlu- ditleretice in the rnrolla of the 
central and exterior tlowers of a head or uin''t'l, I ilo 
not tVi'l at all sure tiiat ( '. ('. Spreimtds idoa tliat the 
riv ;!orrt^ -ierve to attract in.^cct^. v\ho'«e ai-^ency is 
liiu'hlv advanta:.'eoij>< in the tertili>at ion of plant-^ of 
tii>--i> two order'^. is so far-fetched, a- it may at tir^t 
ipncar : and if it !••• advantatreous, natural stdectioii 
rnav liav«> curne into pliv. I>ut in retrard to the ditfer- 
cnces both in the nilernal and t-Mi-rnal structure of the 
-tM'ds, which art' not al'.Navs cMrrtdated with atiy dirfer- 
(Mices ill the llnwcrs. it ^.ceni^ iinpo^^ihlc that they can 
he ill anv "av ad\antaircou-> to the plant: \ct ill the 
I 'nilifP'tfra' Up'-c di'h'rcnccs are of sm-h appartMit iin- 
Ti'irf-ince t!ie seels hcinu' in Honie ca«.t>-, acccrdin-r to 
I'auch. oi'tho-piTinou^ in the exterior tlowers and 
codo^pernious in t}ie central tlowers,— that the elder 1 )e 
( andolle founded liis main division- o! the order on 
analoiroiis ditierences. I lence we see that modit'ications 
iif structure, \ie-.'.ed hv svsteniati-ts a- of h'i:li value, 
mav he wholiv due to unknown laws of correlated 
irrowtli, And without hcinir. as far ns •. e can se-.', of the 
-liiziite-t service to the species. 

NV'e may often fal-elv attribute to correlation of 
LTowth, structures whicli are coiiunon to wlmle trroups 
ot sjifi-ies. and vfhich in truth are simply due to in- 
iierit.aiH'e ; for an ancient proirenitor mav have aei|uired 
throutrli natur.ll neleotion some one niodit'ication in 



>»trui'tiiri', ami, attt-r thousaudH (.{ 4f«Mier.itt(iii>., stirne 
(illirr aiitl iiul»'li»'ii(leiit niodiruaticin ; and thes«> two 
nit>tli(ii;iti()iis, h.'isiu^ l»eeii triiii'^niitti'd l«i a wlidle irrtnip 
of ilfMi-miaiits with >iivt>rso lial^.ts, wdiild iialiiriiliy l'«- 
thoutfiit to (>«' correlated in some iiptessary niainn-r. 
So, »u;aHi, I <1<» in't doulit that «»<)me ap|>areiit tnrrela- 
tion«, onurnin; throupli.tiit whole orders, are<l\ 
due to the niaiiner alone in wlinh natural -.•lertion can 
Hi-t. For instame, Alph. 1 >e ( andolle ha* reniarke<; 
lliat \vince<i s«eds are never found in fruit» wliicli d' 
not open; I -hould explain tkie rule l>y the fact that 
-eeds could not trradually hemnio wiiit'ed tliioUL'l 
natural selection, except in fruits which opened ; ►•<• 
sliat tlie individual pliii's produciriir aeed"* which weii 
a little better tilted to he'ted further, mijfht e'"' '■*'> 
advantaije <)\er those producing M't'd less titled lor 
i!i«per>.'il ; aii<l thin process coiild not po^^lhly e*> '•'■ i" 
Iruit whuli did not open. 

'Hie elder <ie<)tfroy and doelhe propounded, nt ahoip 
th«' >aine |iennd, their law o.' compensation or halatic,"- 
menl ot t,Mi)wtli ; or, as lM)ethe expre->ed it, ' in or-ler 
to Kpeiid on one >ide, nature is forced to eoonopiise on 
the other Si'le." 1 think this holds true to a lertv.m 
extent with our doii.e«tic pro<luclion>< ; if nourishment 
t'ows to one part or oriran in excess, it rarely tlous, at 
least in excels, to another part ; thus it is difficult t" 
iret a cow t<« trive much milk and to fatten read!) 
rhe same varieties of thecahhaire do not yield ahun-iml 
and nutritious foliage and a cojcous siij)ply of oil-heannt; 
seeds. When tiie seeds in our fruits hecome atroptned. 
the fruit it-elf grains larjrely in si/e and quality, iti 
our poultry, a larj^'e tuft of feathers on the head i^ 
i^-enerully aciompanied hy a diminished comb, and .\ 
lartre i;e:i.rd *)y diminished wattles. W ith species in i 
state of nature it can hardly U^ maintained that the law 
is of universal application ; hut many ^ood observers, 
more e-iieciallv h<>t;inists, l)elieve in it.s tru'I, 1 will 
not, however, here tivc any inst;tnces, for I st)« harili\ 
any wav of distin^ruishinj; between the effect-, on tlie 
one hand, of a par! heiiu: lartrely developed throut'h 

••* V 



(»N niK OHM. IV OK M'K( IF> 

natural m-Iim 'idii ami aiioflicr atni ailiniiiiiii: |.arl Im' n^ 
ri'ilurcil li\' tins satiM' proi •■-■* m \<\ (lisiis«>, atid. un th« 
otluT ! i.!!!, fin' a< ti;.il M it)iilra*\.il nt iii'fritmMit (roiii 
oiu" |>;.rt i)vi;rii,' to tlif excf-.- of' LTowfti in aiint'lKT arni 
atlioiniii.' part. 

I ••u'«i'«'<t . aUu, 111 at -onio <if tl.t- 1 i-rs of cornMJMisiitinri 
wliirii hi\«' hetTi a<h.iiii f(l , arid iiKcwise 'tomr other 
tartn. riiay (>•■ nuTL'*"! uikIit a rruut' i;«'ii»'ral [»ririripl«', 
i:aiin''y, that ii.iturai -cIiTtiitii i-. i ni.tiiniail} tryitii? to 
»*<'(iniirhi><> in «".t'r\ part ct iln* ora'aMi*,itnin. If under 
<"lri'"r«'d (oniiif ii.n-, of jiff a >tr ctiri' hcforr useful 
h«'tiifuf<i li*»- u-cful, any diniriution, liom \cr sltirlit, iii 
it-x (l»n»'!i>[»nu>tit, v\ii! li»' «('i/.fd dn hv natural ^cUmiioh, 
for it will profitth*' individual hot to havp it," nutniiient 
wa^tfii in iHiildimr up an u-t-lc-M structure. I inn thu<» 
onl\ liiMlfr-tarid a lait with which I was much "truck 
v» hen ev.iininiti:.' cirripedes, atid of which nianv other 
in.-tar:ce> eould ite iri"-'''!: namely, that \. hen a <irripede 
is par-isitic within another and .» thu-* protected, it lo«e^ 
more or le-- coMip!etel\' it^ own -hell or carnpace. Thi'* 
i-" tiie ca-e with the oiaie lld.i, and in a truly extra- 
ordiii.iry rnaniier wit h the I'rotfolepas: tor the carapace 
m ail other cirrijiedr-; eoii-ist- of the three hitjhlv- 
Mopt.rtant anti-rior Sf:."nents of the heafl enormously 
developed, and turni-hed w .r!i trreat nerve* and muscles; 
hut Ml tlie para-iti<- and proterteil I'rotetdcpa^i, the 
whole anterior part of the head i.>< reduced to the merest 
rudiiueiit att;vcheil to the lia-^i-of the prehensile anteiuue. 
Ni'vi i]\f s:\\ \:iis of a larre atid com|de\ structure, wiien 
rrndere<l superiluou-' hv the parasitic hahit- of the 
]':• 'colcpa.s, tiiou:rh e:(ecti'd hy slow steps, w.uild 1>« a 
«lecided ad^a:lta^'•e to e.uh successive individual of the 
species : fur in the -trutTi:!'' t"r life to wliich every 
atiiTual i" e.xpo^e-!, each individual I'roteolenas would 
have a t'citer ciiauce of siipportiiiir itself, hy ie-<s nutri- 
ment hem..'- vfa.stod in develo[>in:r a structure i.iw 
he«'iitne ustdess. 

1 hus. as 1 helieve, natural selection will always 
succeed Iti the 'oriir run in retluciii:.' and -avintr every 
|iart of the ort:aiii.sation , as <oon as it is renilerod sup«r- 



U) t.o l-irc'ly )1»'\c1o|km1 hi n « (irr»'«jHiii(liiii;f .l.vri-f. 
Atni. <<»ii\«'r^»'lv, tilt! iiiitiinl m'1«'< tmii lu.iy |.«Ttf. tly 
v%rirMJi-<'»'t"l m lariTi'ly <ii'\fl"I'ii':: .-wiy ..rcaii. NMth..iii 
i»<iiiiriiiL' ik-* a iitvi'-sary .■ tin* ri-dmii-.n nt 
H4)riu' aiiin'tiitiif [i.irt. 

It Hc.-ni". t(i l>«' a rul«', i\h r.iri.trk.-d l>v I-. <.»'.'i'r..y 
^t lll.iin-. tx.tli ill \arn'ti«"t .iixl m «[m'<-i«-.. thai whi-n 
.t>i\ |i.iit or '<T-j:\u i- r» i>«'iif«l Miaiiy tiiin-s iii tin* striu- 
luro (.Jtli»« «;«tnf (.-i.- tl..- vcrU'l.r:.- iti -tLi^e-, 
and thf sLiin«Mi« in (".lyriiKlroii!* fio^iT-) th«' iimiil..T i- ; « ln-rt-.x^ tlie iiiitiil>«'r nt the sanie |i.irt i.r 
ort;i!'. «l'«'ii 'I <"«tirs in h^-er miriil>«T«., i.' nui-tant. 
'Hn- >" rinthnr and ^onu- hnf.ini-t.M h.i\»' turtht-r 
remamed t)i:it nniltiph- |«ar;.-. arc :i\'<i> \.Ty IiaLu* to 
variatii.f. in structur*'. Iiia-fnuch a- thi-< ' \ri.'»-t.itive 
repftition.' t«» i»-«' I'roC.wsnr « )wfn's .•i|.ri->.i<.n, •■••vm- to 
iii«aNi.'n<>t"l<'\»' torc!."'iiit.' i«f> -irk ^••^•In> 
cnn.-.l.'d v»ith the very ircnrr.ii n|.nii<'ii <.l n.ktur.ili-ts 
that l.t'in;rx l<»w in tht- .-VaU' i.t natireare tiH.rt* MiriahU- 
than thoM- whiili art- nijlu-r. I pie-ume that !..ui.f» 
m th;H ca-^e moans that tlie se\.T:il part- <.t the 
or^ have hr.'ii hut littU' -[..•- lah-.'d for 
Darticiihir tunrtions ; and a> h)iiir a.- th.- -:uii«- [-.rt has 
•o pert. inn diversified work, we fan perhaj.* -•••' why it 
-houhl remain variahh-. tiiat 1.-, why natural -eU-.i ..n 
nliould iiave preserved or reif. t.d each little deviat;..n 
of form less earefully than w lien tlu' part h:w to serve 
for one sperial purpose ah-ne. In the same way tliat 
a knife which has to t-tit all -Tts of thin-s may he of 
almost anv shape; whiUl a tool tor s.itne par'Huiar 
ohieot had'hetterl.eof some parti.ular ^hape. Natural 
^eleetion, it shoiil.l never he for...tten. .an act on ea<-h 
part of ea.-h heiiifr, solely throu-h and for its ad-.antatre. 
Ku.limeiit.irv parts, 'it has heen stated !■> -omo 
authors, and Thelieve with truth, are apt to he h u'iily 
variahle. U'e shall have to recur to the t<'"tTal 
Huhjeit of rudimentary and ai.orie(i or:rins , an.i i v^.ii 
i.ere onlv add that their variuhility seems to he owintr 
to the.r ii^ele-siiess, and therefore to natural sele.tiou 




h.ivinjf no j.ovror t(» clieck deviations in their Btructuri-. 
'i litis rudiriuMit.iry jiarts are left to the free pl.iy of the 
various laws of trrowth. to the effects oi loiitf-tontiiiued 
disuse, atnl to the tendency to rever>ii(»n. 




A fKirt (it'frld/H'ti in iihy xpecift in an extraoniiniiry 
di'iiret- or imumer, in iniiif>nri*i>n u-ith the aninc purt itt 
(illit'il KV" ii'K, tfiidK to hp hiijhly variiihlf. — Several years I was much stnn-k with a remark, nearly to thn 
ahove erfei t, piililislied hy Mr. W ater)i<ui<e. I infer 
also from an oh-ervation made hy I'roles-or (*wen, 
with respect to the leriL'th of the arms of the ouran:;- 
outant.', that he has come to a nearly similar conclusion. 
It is hopeless to attempt to convince any one of the 
truth of this pro[>ositioii without pivin;^ the lonir array 
of facts which 1 have oolle«:ted, and which cannot 
[(ossihiy lie !iere introduced. I can <uily state mv 
coiniction that it i» a rule of hijrh jreiieraiity. I am 
aware of several causes of error, hut I hope that 1 have 
niaile duo allow;nico for them. It (diould he under- 
stoo<l that the rule hy no means applies to any part, 
however unusually developed, unless it he unusually 
de\ eloj)ed in coinpari>on with the same part in cl(»selv 
allied ^J)ecies. I hus, the hat's wiiiff is a most almormal 
rttructure in the class mammalia ; but the rule would 
not here apl>ly, l)ec.iu>e there is a whole trroup of !>.'its 
havintr winirs ; it would ajiply only if some one species 
of hat had its »iiii:s developed in some reniarkahle 
manner in comparison with the other spei-ies of the 
same trenus. The rule applies very stron^rly in the 
CAse of secondary sexual characters, when <lispl,tyed iu 
any unusual manner. Die term, secondary sexual 
rliaracters, used hy Hunter, applies to characters which 
ari' attaclied to one sex, but are not dire<"tlv connected 
with the act of rfjtroduction. 'ilie ruleajiplies to males 
and females ; hut as females more rarely offer remark- 
able secondary ch.Tracters, it applies more 
rarely to liieiii. i he rule bein^ so plainly applicaide 
in the case of secondary sexual characters, may Ihj due 
to the e:reat variability of these characters, whether or 




not displaypti in any unusual manner of which fact 
I think there can he little douht. Uut that our rule ih 
not conftne*! to secondary sexual characters i8 clearly 
shown in the t-'i>e of herm.'phrodite cirripedoa ; and 
! may here add, that I particularly attended to Mr. 
W'aterhouso's remark, whilst invcsti^oatintr this Order, 
and I am fully cimvinced that the rule almost invari- 
ably hol(l< yood with cirripedes. 1 nhall, in my future 
work, erive a list of the more remarkable raseu ; ! will 
here onlv hrieily irive one, as it illustrate^ the rule in 
it>4 lartrest appliiation. Ilio opercular valves of Hesflila 
cirripedes (rock Warnados) are, in every Ben>-e of the 
word, verv imjn)rtaiit structures, and they differ ex- 
tremely littie even in ditterent genera ; hut in the 
several speiies of one ^enus, i'yrs;oma, these valves 
present a piarvj-llous amount of diversification : tho 
homolotrous valves in tlie diHerent species l)ein(r some- 
times whidly unlike in shape ; and theaniount ot var.a- 
tion in tho individuals of several of the Kpecies \h 
no preat, tliat it is no exatrireration to state that the 
varieties differ more from each other in the characters 
of these important valves than do other species (»f 
distinct penera. 

As birds within the same country v.irv in a remark- 
aMv Pmall decree, 1 have particularly attended to 
them, and the rule st-cMns to me certainly to hold jrood 
If! this class. 1 cannot make out that it ap{»lie< to 
plants, and this would seriously have sliaken my Udief 
in its truth, had not th»" jfreat variability in plants 
made it particularly difficult t<> compare their relative 
decrees of variability. 

NV'hen we see any part or «)rean devclo{)e<l in a 
remarkable dep^ree or manner in any opecies, the fair 
presumption is that it is of hi;.^h imjuirtance to that 
spe«:ies ; nevertheless the part in this case is eminently 
liable to variation. \\'hy should this Iteso.' ( )n the 
view that each species has been indei'enderitly created. 
with all it« parts as we now see them, I can see no 
explanation. Hut on the view that jfrouns of specie* 
have descended from other sj>ecies, and have l»een 




riiM'iitipd tlirmiirh -ifU-ftidii, I think we i-,in 
ol»tain Mima li^lil. In our (Inrnc-tic animals, it" any 
part, or tli«' whole, he rietrlected fliid no splec- 
tioji Im^ a|tj»lieil, ihar jiart (^tor iii^tam-e, the romi) in 
tlic Dorkinu fowl) or the whoh- hrenl will rea'^c to liavti 
a ncirly uniforin character. The hreed uill then he 
said t(t have dcL'eiierated. In rudirnent.'iry riruans, 
and in thn-e which have heen hut little specialised for 
any particular pnrpo^^e. and perliaps in p'tivrnorpl.ic 
trroups, we see a nearly parallel n-vriLOii case; tor in 
such c.i.-es natural .•^eiectinn eitlier lias not or cannot 
roiTie into toll play, and tliiis the orj'ain-atinn is left 
III a tiiictuatine: condition. Hut what here more 
especially coii<eriis us is, that in our «loniestic animals 
tiiosH points, which at the present time are urnltTiroin:;^ 
rapid chaiiire hy continued selection, are al-o emi- 
nently liahle to variation. I>ook at the hreeds ot the 
piireon ; see what a prodijfious amount of difference 
there is in the heak ot" the different tunJders, 'u tlie 
heak and wattle of tlie «lirferent carriers, in the 
carriatre and tail ot" our fantail", etc., these }>einp the 
points now mainly attended to hv Kntrli^h fanciers. 
Kven in the suh-hreeds, a.s in tlie short-ta« ed tumhler, 
it is notoriously difficult to hreed them nearly to 
|>erfei tion, atid t"re<iuently itidividuals are horn which 
depart widely from the standard. Iliere may l>e truly 
paid to he a constant striUTiile fr<»in{j oti l)etwfen, on 
tiie one hand, the tendency to reversion to a less 
mollified .e»ate, as well a.s an innate tendency to further 
varialiihty of .ill kiinN, and, on the othe? hand, tlie 
pow« r of steady selection to keep the breed true. In 
the lonfif run selection trains the day, and we do not 
expect to fail so far iis to hreeil a hird as coarse aa a 
eoinmon tumlder frotr a jrood .«hort-faced strain. But 
a^ louir as selection is rapidly ^omg on, there may 
always Ke expected to he much variahility in the ."truc- 
torc !i!:der=r"irii; Jn'>'li!icatioT!. !t f-irther derervea 
notice that these variable chara<ters, produced by 
mauH selection, sometimes l>e((>ioe attached, from 
causes quite unknown to us, more to one sex than to 



the other, freiienilly to tlie male wex, as with tiie wattle 
of carriers ai:<l tlie eiilartred crop of pouters. 

Now li't us turn to nature. >\'h<'n a pstrt has l>opn 
ilfveh)ped in an extraordinary manner m any one 
rtjioiios, compared wiili the other species of tlie -vune 
^enus, we inav concl;;ile that this part has undergone 
an e.xtraordinarv amount ot nioditication since the 
[leriod when the species hranchod utf from the cninmon 
pro{r«'iiitor of tJie t:«'nus 'l"his period will sehiom he 
reiiKite in any extreme tletrree, as species very rarely 
endure for mure than one ir« <>lo^'ical period. Aa extra- 
ordinary amount of modification implies an unusually 
lart:e and loinj-continued jimount of variah.lity, which 
has continually heen accumulated hv natural selection 
for the henetit of the specie>. Hut is the variahility of 
the extraordinarily-<levelnpe<l part or ortjan lias heen 
so g^reat and l<tri:;-continued within a period not exces- 
sively remote, we mitrht, as a (general rule, expect .still 
to find more variahility in sucii parts than in other 
partis of the organisation which have remained for a 
much long-er period nearly constant And this, I am 
convinced, is the case. That the stru^fcle between 
natural selection on the one hand, and the tendency to 
reversion and variahility on the other hand, will in the 
course of time cease ; and that the most ahnormally 
developed or^rans may V- made constant, I can M'e no 
reason to douht. IJence when an ortran, 
ahnormal it may be, has been transmitted in appnixi- 
mately the same condition to many modified descend- 
ants, as iu the case of the wini^ of the hat, it mu.«t 
have existed, accord in;; to my theory, for an immense 
tyeriod in nearly the same state ; and thus it comes to 
1)6 no more varialde than any other structure. It is 
only in those in which the modification has lieen 
comjiaratively recent and extraordinarily groat that we 
outrht to find the (jmcrntn'e i^iriahUity, as it niay be 
called, still Dr(»sent hi a hiirh deirree For in this case 
the variahility will seldom as yet have been fixed by 
the continued selection of the individuals varying in 
:he required manner and det'ree. and hv tlie continued 



r»'je«tion of tliosc teudinp to revert tc a tormor and lenjj 
Mioilitifd condition. 

Thp prinriple included in tlu'M- n'tiiarks may U- 
extended. It is notorious tliat specitic characters ar« 
more varialde than t^eneric. To explain by a simple 
example what Im meant. If some npet^ies in a larjje 
trpiiu^ ot jdants had blue liowers and ^.ome liad re<i, the 
colour would he onlv a Kpetific c liaracter, and no one 
wtiuld Ite surpri>.cd at one of tlie blue ^[lecies \aryniir 
nito red, or conversely ; but it all the species had blue 
thtwer^, the cidour would iK'come a t'^'xric diaracter, 
md its variation would be a more unusual cinurnstance. 
I ha\e chooen this example t>ecause an explanation is 
not in this case applicable, which most naturalists 
would ad\ance, namely, that wpecitic characler- are 
more sariaido than generic, because they are tiketi 
from p.irt> of less physiolotrical imporUmce than those 
innimoiily used for dassintr i:enera. I believe th - 
explanation is partly, yet only indirectly, true; J 
«lia!l, however, have to return to this subjeit in our 
chapter on ( lassitication. It wouhl be almost 8U|)er- 
fhioiis to a4lduce evidence in pujtport of the alfove 
Ktatenu'iit, that specific characters are more variable 
lliaii fr,.|i«'ric ; biit I have repeatedly noticed in works 
on natural hh^tory, thai when an author has remarked 
with sur()rise that soine xnijxtrunit or;;an or J'art, whicii 
is treuerally very constant throutrhout lar^re ifr<uips 
ol sj»eiies, has liifffrfd considerably ni closely-allied 
(jpccies, tliat it has, also, been vnriii^'/e in the in<iividuals 
ol some lit the sjK3cies. And this fart shows that a 
character, whieh is g^enerally of ^'•eneric value, when it 
sinks in value and beccmies only of specitic value, often 
tuMuiries variable, though iis ]diytiioloifiial importance 
mav remain the ^aine. S«imeihinfj of the same kind 
applies to monstrosities : at least Is. (ieotfroy JSt. 
liilaire seems to entertain no doultt, that the more 
at! '>rL''i!> !!orn!-:'J!\' ditfers in tlio dirterent sppiie-s of 
the same jfroup, the more subject it is to individual 

I *n the ordinary view of each species having l»eeu 




inflepeudeiiUy cn'.itfil, why ^}ll)ulli tliat part of the 
■tnictiire, which rliffers from the same part iu otlior 
iiideperuitMitly-rnvited speries of the same tr»Mi'i'<, he 
niort' varialilo than tli(t-« parts whiih are ( loselv .iIiK«? 
in t)ie >ev(«ral speci»'«*.' i do ii«>t ^«*«> that any explana- 
tion can ho tri\»'". Hut on the view of spcries beiiij^ 
only «troiitrly marked and fixed varieties, we mi^ht 
surely e\{»e(t ti» find them still otteri conliniiinjf to 
varv in tli()>e jiarts of their Ntruetiire wjiirli have varied 
within a moderately recent period, and which have 
thus come to differ. < >r to state the case in ano'lier 
manner : — the poinb* in which all the species nf a 
tfenws resemhle each other, and in which tliev d'tfer 
from the species of 8«»me oilier serins, are called ireneric 
cliaracters ; and tlie>-e cl ; acte^^ in common i attri- 
hute to inheritance trom a common [•ro^'-enitor, for it 
catj rarely liave hap[)e;ied that natural selection will 
have modified several species, fitted to more or less 
widely-different liah.ts, in exactly tiie same matincr : 
and as tlie-e socailed ireneric characters have lieen 
inlierited from a remote period, since that periixl w fien 
tiie species first hram-hed oif from their «'(minion pr<.- 
trcnitor, and suhse<inently have iiot varied or come to 
differ in any deyree, or only in a sliijiit detrree, it i> 
tiot prolialile that they should vary at the pre.-ent day. 
( )n the other liaiid, the points in which -pciies diif.-r 
from otlier species of tlie same ffeniis, are calleil specific 
characters ; and as tlie-e •.j)ecihc <'iiaracters have varied 
and I'ome to difier within the period <.f the hranchiinr 
off of tlie species from a common proireintor, it is 
j>rnhal>le that they should <till often he in some de;rree 
vanalile. at least more variahle tiian those parf> of 
the oriranisation whicli have tor a verv loiir period 
reriiaii'<'d cotist.'int. 

In connection with the p.'-e-eiit ^uhject, I will make 
only two other remarks. I think it will he admitted, 
without my enterintf on details, that secoTidary »ie\iiai 
characters are very vanatde ; l think it aKo will Ikj 
adinitted that sj>ecies of the same group differ from 
each other more widely in their «econdarv 



»»prH, than in oilier j»;irts of llieir ortr.ini-ation ; 
(•(»inj>rirf, for instime, tlM> amount of ilitfcreiice l»et\veeM 
tlie iiialt's of (fallinacfouH hinls, in whifh sproiKlary 
sfxiial charat ters* are stroiiL'^ly disjdayed, with tlif 
amount of <lirt"tTcn<-e between tlunr females ; and tlie 
truth of this prnpo-ition will he trrantt-il. 'Hie rause 
of the ori;rinal variability of secondary sexual characters 
is not nrinife!*t ; hut wo can see wliy these characters 
-ilunild iKit have bpfii rendered as <-onsUint ami uniform 
as (jtlicr parts of the or^ranisation ; for secondary sfxual 
characters have been accumulated by sexual selection, 
whii.-h is less ri^jid in its action tlian ordinary selection, 
as it docs not entail death, but only {,'ive!< fewer otT- 
sprintr to the less favoured males. Whatever thecau>e 
n»ay i)e of the variabilitv of secondary sexual characters, 
as thev are hij:hly variable, -sexual selection will have 
h:.d a wide scope for .action, Riid may thus readily 
liave sucii-eded in trivinir to the 8{H.'cies of the same 
t:n(Up a _'^reater amount of dilference in their sexual 
< liar.Ktei^. tiian in other parts of their structure. 

!l is a remarkable fa<-t, that the secondary sexual 
differences between the two sexes of the same species 
are t:eiierally di<piaved in the very same parts «if the 
or^^ani-;ation in wlii.h the ditferent species of the s;ime 
irenus dith'r from each other. Of this fact I will jrive 
in illu-itration two instances, the first which liapjien to 
sl;ind on my list; and as the ditferences in thc-e cases 
are of a very unusual nature, the relation can hardly 
be accidental. The same numU'r of joints in the tarsi 
;■; a character jfenerally common to very lartre irroups of 
beetles, iiut in the Knt.nda«,as Westwood has remarked, 
the iiumi»er varies trrcatly ; and the number likewise 
ditfers in the two sexes of the same species: a;:ain in 
fos^oriai hymenoplcra, the manner of neuratioii of the 
winirs is a character (»f the hitrhest imi>ortance, Iwcau-e 
common to lari;e ^:roups ; but in certain genera the 
ncii ration ditiers in the ditferent S|)ecies, and likewise 
in tlie two sexes of the s;ime sp«'cies. ibis relatKUi lias 
a cb'.ir me.mins' <»n my view of the .subject : 1 look at 
all the speciCvS of the s;ime jjenus as having as certiiinly 



dforeiided from the same progenitor, as liave tlip tuo 
twxes of any one of the Pi»«'riex. ( onsequently, wliat- 
ever jiart of the stnicturf of tho cijaimori pr<>i:eiiitor , 
or of its oarly <ii'<(«'!i«laiits, ti«'raTiie \arial»h3 ; variatioii«i 
of this part woiihl, it i« liijrhly protwhlp, he taken 
a«lvaiit.i;r<' of hy natural atid soxua! «.-lecti<>ii. in onler 
to tit tlie several -peoe^i to t'leir several plarcs in the 
eroiu)my of nature, ami like« :-e to tit the two sexe><of the 
Rame«.pe(:e-. to each other, or to tit the males ami females 
to difft'rent hahits of life, or the male-- to stniiTL'^le with 
other males for the [>o>^e*»ion of the females. 

Finally, then, I eomlinie tliat tiie irreater variahility 
of speiifie eliararters, or tlio>e whirh <iistiiitrtiish specie.s 
from sjK'eies, than of trt'iieric eharai-ters. or tho>e wliich 
the species i»o-vc--. in common ; -that the freijiient ex- 
treme variahility of any part which is (ioveloped in a 
Bne<ies in an extMonlinary manner in C'>mpari<on witli 
the sjime part in iis eonireners ; and the >iiL'ht deirre*' 
of variahility in a part, however extraordinarily it may 
be developed, if it l»e oomnion to a whole trroiip of 
«})eeies ; —that the ;rr»'at variahility of ^econdarv sexual 
characters, and the trreat amonnt of difference in these 
same characters hetween closelv -allied sjM'cies ; that 
secondary sexual and ordinary specific differences are 
jfeneraily displayed in tiie same parts of tlie ortranisa- 
tion,--are all principles chxely connected to^rether. 
All Iteintj mainly due to the species of the same jrroiip 
having deseemied from a common progenitor, from 
whom tliey have inherited much in common, to parb* 
vrliich have recently and lirir*'Iy varied hfin;,' n\ore 
likely still to go on varyin;i: than parts which have 
lonL'' heeii inticrited and iia\e not varied, to natural 
sele«'tion liavin.-- more or less comp!et»dv, accordin^f 
to the lapse ot time, overmastered the tendency to 
reversion and to further variahility,- to sexual selec- 
tion hein;r 1»'"^"* ritnd than ordinary s<dection, — ami to 
variations in the same parts havinjr heen accumulated 
by natural and sexual seieciion, ami tia\ iiiir t>een ttiUH 
aiiajttcd for secondary wxual, and lor ordin.iry specific 



IHxIiurt Mpirif.i prrxtntt atiii/nijon* inrinfion* ; and a 
inriet^ of one xfifiii-s offfii a^ttniTwn noine of' thf rhararterx 
,tf an nliied npfcwx, or rrvprtt to noruf of thf rlturactem vj 
an enrltf jiroijeuitur. I'liese propositioiin will be most 
nvidilv liridtTstoiMl hv !<»(»kiiiir tn our domestic races. 
The tiirt«t distinct breeds of pijfeiMH, in countries most 
witlely apart, jiresentsul^-varieties with reversed feathers 
oil the head and featliers on the feet, iliaracters not 
j)os>ies>t'd hy the ahorii:iniil roek-|»itreon ; tliese then 
are anilo:;ous variations in two or more distinct races. 
I lie fri'c|uent presence of foiir»»'en or even sixteen tail- 
featlier-. in the jH)uter, may he oiisidered as a variation 
representing the normal structure of another race, the 
faiiUil. I presume that no one will doubt all 
su<h anahtjrous varinti()ns are due to the several races 
of the pijjeon havintf inherited from a common parent 
the ^.UM(> constitution an<i ten<lency to variation, when 
acted (in I>y siruilar unknown intUicnces. In the vetje- 
tihie kinirdom we liave a case of analo^fous variation, 
in the eiilartred stems, or roots as commonly called, of 
till' Swedish turnip and lluta hatra, {)lants whidi several 
hotani-ts rank Jis varieties produced hy cultivatiiui from 
a ctuiunon parent : it this he not so. the case will then 
he one of anri'.'ijxnus variation in two so-caUed distinct 
KjM'cies; and to these a third may he added, namely, 
tiie common turnip. ,-\ccordi:iir to the ordinary view 
of each species ha\ins; been independently created, we 
Hhould have to attribute this similarity in the enlarged 
Btems of the<e three plants, not to the trrn vnum of 
community nf dex-cnt, and a conse(juent tendency to 
varv in a like m.iuner, but to three separate yet closely 
rcl.itcii acts of creation. 

With ])itreoiis,]iowever, we haveanotlier case, namely, 
the MC(a>.ioiial appearance in all the breeii*. of slaty- 
blue birds with two black bars on the wiuL'-s. a white 
riimj.. a bar at tlie end of the tail, with the outer 
feathers externally ed:;ed near their bases with white. 
A- ail liiese marks are characteristic ol liie parent rock- 
piireun, 1 presume that no one will doubt that this 
is a raM* of reversion, ar.d not of a new yet analojrous 




v;iri,ifi(tii apiMviring' in the several hret-ds. We rnav. 
I flunk, cniiti'loiitly come to this coiirhision, l)eiMiii)«e, 
a^ we li.ive s«'i'ii, these coloured marks are eiiiinriitiv 
ii.'ilile to apjiear in the crosserl otf>prinir of two dihtinct 
:iMd diiTereiitly coloured hreeds ; and in this ca^Nf there 
!■* Mothintf ill the external ctJiidifions of lite to raijue 
the reapjiraraiice of the slaty-ldue. with the several 
marks. Iieyond the influence «»f the mere act of crotif'in^ 
on the law- of inheritance. 

.N'o douht it i- a very sur|>risinir fart tiiat charattern 
should reajipear atler haviinr heen lo<t for many, per- 
ha[»« tor hiindr<'(ls of ireiicration.s. Hut when a hret'd 
has lic»'n crossed only once hy some other hreed, the 
oti^prinif occasionally show a tendency to revert in 
character t<» the forei^'n hreeti for manv jfenerations — 
sorrif say, for a do/.erj or evei' a score of generations. 
After twelve treneraf ions, the proportion of hlood, to 
use a comnuMi ex[)ression, of any one ance-tor, is only 
1 in U(i41t ; and yet, as we see, it is treneraily heiieved 
that a tendency to reversion is retained hy this very 
^mall proportion of foreitrn hl(M>d. In a hreed whicii 
has not lieeii crosseil, hut in which hoth jvirentu have 
lost s<irrie character which their proy^enitor possessed, 
the tendency, wlietlier strontr or weak, to reproduce 
the lost character niitrht l»e, as wa.s formerly remarked, 
t-r all tliat we can see to the contrary, tnmsmitted for 
almost any numher of generations. When a character 
which ha.s heen lost in a hreed. reapjM'arf' after a ^reat 
niimiier of trenerations, the most prohahle hv{)ot)ie«is 
i-^, not that the offspriiitr suddenly takes after an ancestor 
some liundred penerati(»iis distant, hut that in each 
*!icies-i\ e tTPner.itioii there heen a tenden<-v to re 
produce the character in (juestion, which at last, under 
unknown favouralde conditiitns, trains an ascendancy. 
For iiist.tfK'e, it is prohahle that in ea<-h generation of 
ttie Iwrli-piireon, which produces mtwt rarely a blue 
.'iiul |il;ii'L -Ji^rraij hlrd, th«*re haH Ise^fi a tPTuii^fscv ip 
fa< li generation in the plumaffe to assume this colour. 
This \iew Ih hypotlietieal, hut could he su;ijM»rt«d b\ 
soTiie fact>» ; and 1 can see no more ahstract improba- 




11 ^ • 



! V 

bilitj in • tendency to prodiue any chara»"t«r l)Oiiin 
inherited for an endlesH niimUer of generations, tli.nii 
iu quite iJhj'IcHH or rudimentary ortfans beint;, a« we all 
kn<iw tliem to be, tlius inherited. Indeed, we may 
MjiiiftiiM»5H observe a mere tendeiwy to produce a rudi- 
ment inherited : for instance, in the common snap- 
drajfon (Antirrtiinum) a rudiment of a fitlh stJimen fw> 
often a{)pears, that this plant must have an inherited 
teiideiir)' to produte it. 

As all the species ot the same t'enus are suppo^fd, on 
my llieory, to have descended from a common narent, 
it tiiicht i>e expected that they would O' isionally vary 
in an analo^fous maimer ; so that a variety of one -pecies 
would resemble iu Home of its characters another 
species ; this other sjieciea heintf on my view only a 
well-marked and permanent variety. Hut characters 
thus jraiiied wouhi prol»a!)ly 1»« of an unimportant 
ti.iture, for the presence of all important characters 
will he >/-overiifd by selection, in accordance 
with tlie diver«» habits of the species, ami will not be 
left to the mutual action of the conditions of life and of 
a -iuiilar inherited constitution. It mitrht further he 
expected that the species of the s;ime pen us would 
occasionally exhibit reversions to lost ancestral char- 
ai'ters. As, however, we never know the exact char- 
acter of the common ancestor of a irrrxip. we could not 
distiiurui^-h these two cases : if, for insUuice, we did 
not know that the rock-pigeon was not feather-footed 
or turn-crowne«l, we could not have told, whether these 
characters in our domestic breeds were reversions or 
only analogous variations ; but we mig-ht have inferred 
that the blueness was a case of reversion, from the 
number of the markings, which are correlated with 
the blue tint, and which it does not appear probable 
would all appear totjether from simple variation. More 
asiM'ciallv we mitrht have inferred this, from the blue 
colon rand marks so often anpearinL'' when distinct breeds 
of diverse colours are crossed. Hence, thoutrh under 
nature it must generally l>e lefl doubtful, what case^ 
are reversions to an anciently existinc character, and 




what are new but anaIo(roui« variations, y^t w* ou^ht, 
on my tlipory, nometinioii to find the varvin^ offsprin^f 
nf a sppciwi aMumintf charact«»rM (either from reveraiun 
or fr(»m analoirniiH variation) wliirh alTa<ly occur in 
Hom«« oth«>r mpmiier« of the saiiie f^rnup. And thi« un- 
doubtedly is the cane in natunv 

A ciinxideralile part of the diffiouity in reroirnixitiif a 
varii'il»» p[»t»nps in our »yKtomatic w«irks, is due to it« 
varieties mockitnf, as it were, some jf the oth«'r spe<-i»'», 
of the fcimo t:iiiiis. A ronsiderable catalo^^ue, also, 
rould he civeii of fnrniH intermediate between two Mther 
forms, whirli themselves must he doubtfully ranked an 
either varieties or species ; an«l this shown, unless all 
these forms he considered as independently created 
"jierit's, that the one in var; injf h.-w assumed pome of 
the chararters of the other, ko as to produce the intcr- 
nii'diate form. Hut the best evidence is afforded by 
parts or nrrraiis of an important and uniform nature 
• '(•capionally v;iryin»f so as to acijuire, in some de^free, 
the charartor of the same j>art or or^ti in an allied 

le i>a 
a loi 

species. 1 have collected a lonjf list of such ca.nes ; but 
ho-e, as before, I lie under a jfreat disadvanta^re in not 
being able t<> >five them. I can only repeat that such 
cases certainly do occur, and seem to me -"ry remark- 

I will, however, give one curious and complex ciise, 
not indeed as atfectiu^ any important character, but 
troin m-curriiitr in several species of the same *renus, 
partly under domestication and partly under nature. 
It is a case apparently of reversion. The not rarely 
has very di>tin(t transverse l»ar« on its letrs, like those 
on tlie le::s of the zebra : it has \teen asserted that 
these are plainest in the foal, and from inquiries which 
I have made, I believe tliis to be true. It has also 
been asserted tliat the .striin; on each shoulder is some- 
times double. 'Ilie *houlder-stri{)e is certainly very 
variable in length and outline A white ass. but no! an 
albirio, liiis he^Mi descril>ed without either spinal or 
shoulder stripe : and these stripes are sometimea very 
oUcurc. or artually quite lost, in dark-coloured ajwes. 




Die knijl.'iii of I'.-illnx is h.i d to have fx'iTi srcii * itli a 
tl(iiili|i« sliiiul(lfr-stri|>«v i lie liernionus hrm no .olinclder- 
fc ri|„. ; \}tii tracj'M (if it, an Mtatrd hy Mr. Ulytli and 
otlif'r><, fx'fi-ionally aii[>»'ir : and 1 liavo Ween itifnrmed 
>>v ( 'iloncl INxile lliat tli»» f(»a!> of tliiH >!|KM'ies <iri« 
/Pdi'rril! V «<tri|i('d «(ti tlie W'tfs, ntid tiiiMtly «»n the 
Hl.iMilitrr. Ilif i|U<i;.'j'a, tliMiijrIi SO plainlik li.irrrd likt; 
» z»diia over tlif Itody, i.s without hars on tli« h'jfn ; tmt 
i *r. (Irav has (iLririd oii»> spiMMnen witli \»Ty disiinct 
•■• i'r.i-lik« Sars un the lio«-ks. 

U'ith r«'sj»oct to fhi< hor^e, I liave rollofti'd raves in 
Kiii^la-id of the spinal >trijn' in hursfs of the iim-t di.« 
Uiirl hre«'ds, ami i»f <;// colours ; transv;-rv« | j,^ ,,„ ^1^. 
!••!> are not ran" in diinn, nioiise-diins, and m one 

ii>ian(e in a c'h«*stniit: a faint shoidder-sitripf may 
«oini-uni«<o ho HfiMi in ituii'<, and I haM> "eeii n trai e in a 
i>av horse. My ?on ni.ide a careful exainin ition and 

keti h lor nie of a dun li<'U;ian «'art-liorse w illi a doutile 
f>tri|>«' oil eacli shoulder and with le^'-strij-e.s ;and a man. 
■>Th(iir, 1 f.-Hi implicitly tru>it, has ex.iiiiitied for me a 
small dun Welch pony with tltr^-e short parallel ^tiipea 
on eaih >lioiilder. 

in the north-we^t part of Imlia the isattywar hieed 
of h(tr»es is so L'ciKT.tilv striped, that, as 1 hear fro:n 
' oionel I'oole, who examined tlie orewl for (he iudiau 
liove^-ninent, a horse witliont '^tripes i.s not con'^idereti 
as piirel\-l)red. 1 He ■'pine is .ihvays stripeil ; tli«" lej-'^are 
treiierally harred ; and the shouider-r-tnpe, whicli in 
sometimes doiihle and soinotimes trelde, is coinmoii ; 
the s(ie of tlie face, moreover, is sometimes striped. 

1 he stripes are piaine.^t in llie foal; and sometinie" 
'|uite d'-appear in »»ld Imr-es. Colonel I'oole li;w seen 
hoth I'r.iv and hay Kattywar hor^-es stripeii when tirst 
foaled. I ha\e, also, reason to Mispeit, from in'ornia- 
tion iriven me hv -Mr. W . \\ . KdwanN. that with the 
KiiL'li-h race-hor-e the spinal stripe i« much commoner 
in the foal than m the tull-irrown animal. Without 
here enteriiitT on further details, 1 may stvte that 1 have 
collectetl of ley^ and shoulder stripes in horses of 
very diticuut hreeds, in various couutrie<< Irou. hritain 



to ^^^st<•rIl ( liitia; and frum Norway in tlic nurtlt tnthf 
Malay Ar«hijK'la;.'(» in tli« wmtli. In all jwirfM of tht* 
worlil tho»<»* HlriiH's omir far oft.'iu'st in duiiH ami rn(»iis«?- 
<ititi> ; l»v lli«» terni dun a lart'e raiik'« «»f tolour is in 
'liulfd, from one l'Pt\vi'fii hniwu and Miuk to ,t clo-r 
H|ii>ro;itli tu tTPam > oiour. 

1 am a.Nart' that ( olonel Hamilton >nntli. wlio lia- 
V ntten on tlii> »ijlii«'<'t, l<oli»*M'n tlial tin* ••♦'vriai i-reed- 
of tlio Imr-o havf df-i <Mid«^l frorii srvprai alMiru' ".il 
u|K•n«•^ oiif uf whicli , tlip dun, »a« htri|K*«l ; and tliit 
tin* il'.ivf dr-tTiU'd appfaraiii )'?< are all <iii«' 'n an" u-iit 
rro--r, witli the dun htork. lUit I am not at all vit;- 
ft«'d with tlii-* tlipory, and should be loth to apply it tc 
l)r*'««(is so di-'tinct as tlip ln-avy Upltian rart -lior»< . 
\\'«'Kh ji"ni»'>, cidis, the lanky Kittywar rare, etc, m 
haliitin/ the most di«tant parts of the world. 

Now let MX turn to the ei!'eetf! of cro^^intr lh<» sever.;! 
spet :e8 i>( the hor>e-»reiMiH. KoUin as.*erts. that 'lie 
coiiimon niule frotu the atua and hor!>e in particularlN 
njit to ha>e hars oji its lej;x : arrordintr to Mr. <Jo-.-e, iu 
«»Ttain parts of the lUited Sta*e.'« alxjut nine out of t.;i 
mule" have strijied let,'"*. I '>n<e saw a mule with iti» ie - 
Ko much strij't'd that any one would at first have thouji^ht it niu>t liave heen the product of a zebra ; an<J 
Mr. W. { . .Martin, in hi>e\«ellcnt treati-e on the hor^e. 
ha- iriven a tiirure of ji similar nuile. in four coloured 
<lrannt;«., which I have seen, of hyhrids l>etween tin- 
ft-"" and ^eiira, the leirs were much more plainl}' hanei 
than the rest of the Inxly ; and in one of tio'm there 
w:'s adouhle shoulder-stripe In l^ord .Morton s famou- 
hyhrid from a chestnut mare and male ijuairiri, t!ie 
liyiirid, and even the pure off^pritiir -uhseijuently pro- 
duct'il from the mare hv a black Arabian sire, were 
much more [dainly barred across the le:r« than is v\cu 
the juire ijuai.'L'^a. i^astlv, and this is another mo>>; 
remarkable case, a hybrid lia.s been fijfured by I>r. (iray 
'and he int'orms me that lie knows of a -econd case) 
ii"in the ass and liie heniionus ; and this hyttrid, 
tlioutfh the ass seldom has stri{)es on hi.s letf? and tlie 
hemiontis has none ainl hat* not even a ••houlder-strip*', 



I n 

nevertheleiis had all four le^ barred, and had three 
short shoulder-stripes, like those on the dun Welch 
pony, and even had Mome zebra-like stripes on the sides 
of its face. \Vith respect to this last fact, I was so con- 
vinced that not even a stripe of colour appears from 
what would commonly be called an accident, that I was 
b d solely from the occurrence of the face-stripes on 
tills hybrid from the ass and hemionus to ask Colonel 
Toole wliether such face-stripes ever occur in the 
eminently striped Kattywar breed of horses, and was, 
as we have seen, answered in the affirmative. 

NVhat now are we to say to these several facts ? We 
see several very distinct species of the horse -genus 
becoming, by simple variation, striped on the le^ like 
a zebra, or striped on the shoulders like an ass. In the 
horse we see this tendency strong whenever a dun tint 
appears —a tint which approaches to that of the i^eiieral 
colouring of the other species of the genus. The 
appearance of the stripes is not accompanied by any 
change of form or by any other new character. We 
»ee this tendency to become striped most strongly dis- 
played in hybrids from between several of the most 
distinct species. Now observe the case of the several 
breeds of pigeons : they are descended from a pigeon 
(including two or three 8«b-species or geographical 
races) of a bluish colour, with certain bars and other 
marks ; and when any breed assumes by simple varia- 
tion a bluish tint, these bars and other marks in- 
variably reappear ; but without any other change of 
form or character. When the oldest and truest breeds 
of various «'olours are crossed, we see a strong tendency 
lor the blue tint and bars and marks to reappear in the 
mongrels. 1 have stated that the most probaltle hypo- 
thesis to account for the reappearance of very ancient 
rhanicters, is — that there is a tendency in the young of 
each succe."vsive sreneration to protluce the long-lost char- 
acter, and that this tendency, from unknown causes, 
sonietinieB prevails. And we nave iu . seen that in 
several species of the horse-genus the stripes are either 
plainer or appear more commonly in the young than in 



the old. (all the breeds of pigeons, some of which have 
bred true for centuries, speries ; and how exactly |»arallel 
is the case with that of the species of the hor»^ 
(fenns ! For myself, I venture confidently to look back 
thoumnds on thousands of g-enerhtions, and I nee an 
animal striped like a zebra, but perhaps otherwise very 
differei.tly constructed, the common parent of our 
domestic horse, whether or not it l>e des«-eiide<l from 
one or more wild stocks, of the ass, the hemionui, 
quacrifa, and zebra. 

He who believes that each eijuine species was inde- 
pendently created, will, I presuine, assert that each 
species has l)een created with a tendency to vary, both 
under nature and under domestication, in this par- 
ticular manner, so as often to b«nome 8tri{>ed like 
other species of the ^enus ; and that each has been 
create*] with a strong tendency , when crossed with s|)ecies 
inhabiting distant quarters of the world, to produce 
hybrids resembling in their strip not their own 
partuts, but other s{)ecies of the ^tiius. 'I'o admit 
this view is, as it seems to me, to reject a real 'or an 
unreal, or at least for an unknown, cause. It makes 
the works of (iod a mere mockery and deception; 1 
would almt'mt as soon believe with the old and iirnurant 
cosmogonists, that fossil shells had never live*!, but had 
bton created in stone so as to mock the shells now living 
on the sea-shore. 

:<ummary. — Our i^aiorance of tlie laws of variation is 
profound. Not in one case out of a hundred can we 
[■retend to assig-n any reason why this or that part 
tiitfers, more or less, from the same part in the parents. 
Hut whenever we have the means of instituting a com- 
parison, the same laws ap{>ear to have acted in pro- 
ituiiiig the lesser differences between varieties of the 
same spe*'ies,aiid the greater differences (>etween s|>ecie8 
of the same uenus. 'ilie external conditions of life, as 

; ;::i:ate arid lOOu, cti":. , ^^C•:K tO have Uiu::i"-rti SOHir slijjht 

nio<lifiratioiis. Habit in producing constitutional dif- 
tereucea, and use in strengthening aud disui^ in weak- 



'■ ti 1 



eniiijT ami diniiiiisliiiijf ortrims, seem to have boon more 
potent, in tlieir ••flertft. Homoi»»;roiiH parts tend to vary 
in tlie same way, an<l homoloifous {)artH tend to cohere 
Moditieation- in hard part** and in external parta SMne- 
tinie^ affect softer and internal parts. When one j».irt 
is lar;rely developed, perhaps it tends to draw n<'uri>;h- 
meiit from the adjoininir partH ; and every part of the 
Btnicture which can he siived without detriment to tlie 
individual, will Ik? saved. ( lian>:es of .structure at an 
early a^e will jr^^'ierally affect parts suhsecjufntly de- 
veloped ; and lin^re are very many other correlations of 
jrrowth, the nature of which ue are utterly unahle to 
understand. .Multiple jKirts are variahle in nutjiherand 
in struct ur5', perhaps arisin^f from such parts not h.ivinj; 
been closely spe<ialised to any particular fuu. tion, .so 
tliat tlieir moditic^itions l.ave not been closely check«'d 
by selection. It is prohahly iVom this Njime 
cause that ortjanic l»einirs low in the scale of nature are 
ni<»re variahle than tho>e which have their w hole ortran- 
isaticMi more specialised, and are higher in the scale. 
Kudimentary or/;ans, from l»ein>f useless, will l>e disre- 
gard. •<! hy natunil selection, and hence proliahly are 
variahle. Specific characters - that is, the characters 
which have vomo to differ siiu e the several s[»ecit><j of 
the same ffenus hranche<l off from a common parent — 
are more variai>le than generic chara<;ier«, or those 
which have lonjf been inherited, and have not differed 
within this same period. In these remarks we have 
referred to special parts or orjfans l»ein>f still variable, 
l»e<-ause they have recently varied and thus come to 
differ; but we have al>o seen in the second Chapter 
that the same principle applies to the wliole individual ; 
for in a ilistrict where many species of atiy creinis are 
found— that is, wlu-re there ban been much former 
variation and differentiation, or where the manufactory 
of new specific forms hjis been actively at work — there, 
on an aversitf-e. we now find most varieties or incipient 

able, and tiuch characters difler much in the sj>eciefl 
of the tame group. Variability in the same p.'irt« of 



the orjrniii nation has (reiiprally heoii takeu ailvautiffc 
of in piviinf se<f»u<lary sexual differente* to the Kexes 
of the same Kpe<ies, and s|>«<'iHc diriert^iues to th«» 
Keveral species of tlie •^nie »feiius. Any {>art or orjfaii 
'ievelopea to an extraordinary size or in an ♦■xtra- 
ordinary maniior, in comparison with tlie sriiiu» part or 
orjfan in the allie<l sp«»cies, must have irorie tlirntiirh an 
extraordinary amount of nuHlifuation since tlie ir<'nus 
:irose ; and tlius we can undiMst-tnd why it shouhi often 
still ()e varial)le in a mucli lii;:lier d»'i:r»'i» than other 
parts ; tor variation is ^ lonir-<'ontinut'd and slow pro- 
cess, and natural selection will ni such ca>es not im 
vet liave had time to overcom*^ tiie teiidem-y to further 
variahility and to reversion to a Icsh modified state, ftut 
when a species with any extraordinarily-<ieveloj»ed oi^^an 
has l»ecome the i>arent of many moditicd descendants 
-wliii'h ou my view must l»e a very slow proci.?^^, 
ret|uirinff a lon^r lapse of time — in this case, natural 
selection may rea<lily have succee<led in ^ivin^f a fixed 
character to the or^^au, iu however extraonlinary h 
maimer it may l»e devolope<l. Speines inheritinij^ ntviriy 
the same constitution fr«)in a commou parent and ex- 
posed to similar influences *ill naturally tend to present 
aualog-ons variations, ana iliese same species may occ-a- 
•■ionallv revert to some of the characters of their ancient 
progenitors. Althoutfh new and important nuMJifica- 
tions may not arise from reversion and analofou-s 
variation, such modifications will add to the beautiful 
and harmonious diversity of nature. 

Whatever the caube may he of each slijrht difference 
in the otfsprinfj from their parents — and a cause for 
each must exist — it is the steady accumulation, thrnujfh 
natural selectiun.of such differences, when l>eneficial to 
the individual, that g^ives rise to all the more important 
mo(lification.s of structure, by which the innumerable 
l>einir3 on the face of this earth are enabled to htruj^^le 
with each other, and the best adapted to survive. 



Dlfflcultlei on the theory of descent with mfxllflcatlon— Tr«n»ltlon»— 
AtiSfiice or rarity of tranaltional varieties— Traniitlnrii In hahlt« 
of life— IXvereifltd hat)lt« in the same species— Species with 
Ji«liit« widely different from Uiuse of their allies- oritans of 
eitreme perfection— Means of transition — Cases of dlfWculty — 
Matura non faeit iolturn—nrfHnt of »matl Importance— orfrans 
not in all cases al)Solutely i>6rfect— Ihe law of I nity of Type 
and of the Conditions of Existence embraced by the theory of 
Natural Selection. 

Ijono l>ef()re haviiifi: arrived at thiw part of my work, a 
crowd of difficulties will jiave occurred to the reader. 
Some of them are so g'rave that to this day I can never 
reflect on them without l)eins: sta^jrered ; but, to the best 
of myjudffment, the greater nunil>er are only apparent, 
and tiiose that are real are not, 1 think, fatal to my 

'l"hese difficultipH and objections may be classed under 
the followiiiar heads .- Firstly, why, if species have 
descefjded from other species by insensibly fine trrada- 
tons, do we not everywhere see innumerable transitional 
forms? \Vhy is not all nature in confusion instead of 
the species beintr, as we see them, well defined r 

Secondly, is it possible that an animal having, for 
instance, the structure and habits of a bat, could have 
been formed by the modifici»tion of some afiinial with 
whoUv different habits? (an we believe that natural 


CO!! Id 



er\t%(h *i>in/4 rkriTQTia tki 

trifliii:; importance, such as the tail of a jjiratTe, which 
stirves as a fiv-flapper, and, on the other hand, ori;;»n« of 




iuch wonderful rtructtire, as the eye, of which we hardly 
an yet fully understand the iuimitahle f)erfe<tion .' 

hiirdly, can instincts be acquired and modified 
through natural selection ? What shall we say to »o 
manellous an instiiut as that which leads the bee to 
make cells, which has practically anticipated the dis- 
coveries of profound mathematicians .' 

Fourthly, how can we account for s|)ecies, when 
crossed, beiiijf sterile and producintr sterile olTsprinjf. 
whereas, when varieties are crossed, their fertility is 
unim{>aired .' 

Hie two first hear diall be here discusseil — Instinct 
and Hybridism in separate chapters. 

(>ti tfw abunu-f. or rarity of transit ionnl i^irit-tie*. — 
As natural selection acts solely by the preservation of 
profitable modifii-ations. each new form will tend in a 
f"ully-stocke<i country to take the place of, and finally to 
exterminate, its own less improve<l parent or other lesi*- 
ravoured forms with which it comes into competition. 
ITius extinction and natural selection will, as we have 
seen, ffo hand iu hand. Hence, if we look at each specie* 
as descended from some other unknown form, Iwth the 
parent and all the transitional varieties will jreneriUy 
nave \>een exterminated by the very process of forma- 
tion and perfection of the new form. 

But, as by this theory innumerable transitional forms 
must have existetl, why do we not find them embedded 
in countless numbers in the crust of the earth } It will 
be much more convenient to discuss this *|uestion in the 
chapter on the Imperfection of ths ^eolo^^ical record ; 
and 1 will here only state that I believe the answer 
mainly Les in the recor<i J>einf? incomparably less perfect 
than is (fenerallv supposed ; the imperfection of the 
record being cliiedy due to ortranic beinjrs not iuhaliitinif 
profound depths of the sea, and to their remains l»einif 
♦'mtiedded and preserved to a future a^e only in masses 
u: i!«niTncut Humriuiiiiy liiJCR anu citriir.ive uj rfiLBz-^-.-.-i 
an enormous amount of future de^n^^tio" '•> *'><i "^^^^ 
foasiIiferouB msMes can be accumulated only where much 




st'dinuMit 18 «le|n>^iie(i oa tlie shallow hed of tlif; ht»5i, 
wlii!-'. it slowly 6ubsi(l«-s. '^lle^e coutinffi'ticicx will 
••niuur only rarely, aini alter »'n<»rin()usly lotifj iiitt-rvah. 
\\ liilst tho lied of the sea is sUitioiiary or is risiiiif, or 
when very little sediment is heiiiL' dejin^jted, there will 
he hiaiiks Ml our f;e<dojjital history. 1 he crust of the 
earth is .i vast riiuseutn ; but the natural eol lections 
have Imcm made only at intervals of time inimen-ely 

Hut it may he urued that when several chwely-allied 
"{■•'lies inliahit the >ame territory we Hurelv ouf^ht to 
find at tho jire-ent time many transitional forms. I>'t 
us take a simple case : in travelling from north to 
Mjii'li over a coiitinent, wo generally meet at siicc('<- 
Hive intervals with closely allied or representative 
«|M'cie,-., e\ideiitly fillinif nearly the same place iu the 
natural econi»my oi the land. 'I'hese representative 
Hpecio often meet and interlock ; and as the one 
becomes r.irer and rarer, the other hecome> more and 
more treijuent, till the one replaces the other. Hut if 
we compare tliese species where they interminjjle, thev 
are generally a.'- absolutely distinct from each other in 
ev«-ry <letail of structure as are specimens taken frrini 
the iiietrop(dis inhabited by each. By my theory the>o 
allud species have descended from a common parent; 
aiMi -iuriu:,' the process of modification, each na.s \>e- 
cotne adapted to the conditions of life of its own 
reirion, and has supplanted and exterminated its 
oritrmal parent and all the transitional varieties be- 
tween its p;ist and present states. Hence we ouKiit 
not to expect at the present time to meet with 
numerouti transitional varieties in each retrion, thoufrli 
they iiiuHt have existed there, and may be embedded 
tliero in a fossil condition. Hut m the intermediate 
retrion, having intermediate conditions of life, why do 
we not now find closely-linking intermediate varieties.' 
This difficulty for a loiitr time quite confounded me. 
liul 1 liiiiik it can be in iarg'e j)art eJiplaiiieu. 

in the nrst place wo should l)e ext.cmely cautious 
iu infernnjr, because an area is now cdntiuuous, that 




It ha-i >><-tMi cfintiiiuoim durintr a \oue i»erio«l. (i«M>l<»tfj 
woiiM h'.id MS to believe that almost every r<»iitiiieiit 
li;i- Keen broken up into islaiuls even duriiiif the laf«T 
tertiary |>er,<i<l» ; and in surh inlands di-^tinct sjK'ciei* 
miifht have h^on pejiaratcly formed without the possj- 
h'lify of intermediate varieties existinsr in the inter- 
mediate ziidps. Ily chatitr*.*! ill the form of the land 
.i!id of eliiiiate, n<arine areas now continuotj"! must 
ulten have exi>ted within re<ent times in a far les.- 
eohtinnoiis and tiniforni toridition than at present 
Hut I v*ill iia>fl over lhi> way of eseaj>ini; from the 
•litlieiilty ; tor I believe that many perfectly defined 
-pecies have been formed on strictly continuous areas ; 
lliuiitrh 1 .io net <loubt that the formerly broken condi- 
tion of areas now continuous has played an important 
jiart in the formation of new species, more espinialiy 
with freely-crossinjr and wandering: animals. 

In lookin<; at species as they are now distributed 
over a wide area, we generally find them tolerably 
nmiierniis over a lar-re territory, then becomiiitf Mime- 
wliit abruptly rarer and rarer on the contineN, and 
tiiiaily disajtpearini.'. Hence the neutral territory \>e- 
tween two representxitive species is jjenerally narrow in 
comparison with the territory proper to each. N\'e see 
the same fact in ascemlinp mountains, and sometimes 
It is ijiiite remarkable how abruptly, as Alph. De 
( aridi>lle has observed, a common alpine species dis- 
appears. 1 he same tact has l)een noticed by K. Forbes 
in soiindintf the dejtths of he sea with tlie dredge. 
To those who look at climate and the physical condi- 
tions of life as tlie all-important elements of distribu- 
tion, these fact- ouirht to cause surprise, as climate and 
lieiL'lit or dep'li trraduate away insensibly. liut when 
we bear in mind that almost every 9pe<'ies, even in 
its metropolis, would increase immensely m numbers, 
were it not for other competiii|f s[)ecies ; that nearly 
all either prev on or serve as prey for other«; in short, 
thai ea»-h ortranic beliiir is eitlier directly or indirectly 
relate*! in tlie most im|Mirtant niantier to other ortranic 

•ein^rs. we rtius 

t st>e that the ranue of the inhabiiaut» 



of any rountry by no means exclusively depends on 
iriseiHibly ch.iti{rin>f physical conditions, but in larjje 
I>art on the presfnre of other KiH»ci«»s, on which it 
depends, or by which it is destroyed, or with which 
it comes into competition ; and as these species are 
already define*! objects (however they may have b«'come 
so), not b!endin*f one into another by insensiJtle ^rada- 
tiojiH, the rarnre of any one specie^, dependinif as it 
does on the ranire of others, will tend to be sharply 
defined. Moreover, each sj)ecie« on the confines of it« 
ranjfe, where it exists in les>ened numlK?rs, will, durinjf 
ductuations in the numlier of its enemies or of itii prev, 
or in the seasons, be extremely liable to utter exter- 
mination ; and thus its jfooirra'phical ran^e will come 
to l»e still more sharply defined. 

If I am ri^ht in belicviritf tiiat allie<l or represent- 
ative species, when iuhabitiiiff a i(»ntinuou8 area, are 
icenerally so distributed that each has a wide ran^jo, 
with a coinjiaratively narrow neutral territory between 
them, in which they become rather suddenly rarer and 
rarer; then, as varieties do not essentially ditTer from 
species, the same rule will pn»bably apply to both ; and 
if we in imagination adapt a varyinjf s{)ecie9 to a very 
lar^rj. area, we shall have to adapt two varieties to two 
larjfe areas, and a third variety to a narrow intermediate 'Hie intermediate variety, conse(|uently, will 
rtxist in les.ser numbers from inhabitinjf a narrow and 
lesser are,i ; and practically, as far as 1 can make out, 
this rule iiolds p^ood with varieties in a state of nature. 
I have met with strikinjf instances of the rule in the 
case of varieties intermediate l»etween well-marked 
varieties in the jfenus lialanus. And it would appear 
from information pven me by Mr. Watson, Dr. ls,i 
(iray, and .Mr. W'ollaston, that jfenerally when varietie* 
intermediato l>etween two other forms occur, they 
are miidi rarer numerically than the forms which they 
connect Now, if we may trust these facts and infer- 
enres, and tlierefore conclude that varieties linking 
two other varieties toj^ether have jfenerallv existed in 
lesser numbers tlian the forma which they connect, 



then, I think, we can understand why intermediate 
varietiea nhould not endure for very long period*;— 
why as a jjeneral rule they hIiouIU '»« exterminated and 
disappear, Hooner than the forms which they oriKinally 
linked together. 

For any form existing in lp>i-<pr numWrs would, tu* 
already remarked, run a greaU^r rliance of InMiig exter- 
minated than one existing in large numliers ; and in 
tliii particular case the intermediate form would !»«• 
eminently lialtle to the inroads of closely-allied forms 
existing orj b<ith sides of it. Hut a far more important 
connideration, as 1 believe, is that, during the process 
of furtlier modification, hy which two varieties are 
8uppo>-»'<l on my theory to i>e converred and perfected! 
into two distinct species, the two which exist in larger 
numhers from inhabiting larger areas, will have a great 
a<lvaiitat'^e over tho intermediate variety, which exists 
in gmalU-r numbers in a narrow and intermediate zotie. 
For forms existing in larirer numbers will always have 
a l>ettor chance, within any given period, of presenting 
further favourable variations for natural sele«-tion to 
seize on, than will the rarer forms which exist iu lesser 
numbers. Hence, the more common forms, iu the 
race fo" life, will tend to U«at and supplant the less 
common forms, for these will l>e more slowly modified 
aii'l improved. It is the same principle wljich, as I 
Ix'lieve, accounts for the common species in ea«-b 
country, as shown in tlie second chapter, presenting 
on an average a ifreater number of well - marked 
varieties than do the rarer species. I may illustrate 
what 1 n>ean by supposing three varieties of slieep to 
to be kept, one adapted to an oxteii>ive mountainous 
region ; a s<'cond to a cnmparatively narrow, hilly 
tract ; and a third to ^vide plains at tho K-.use ; and that 
the inhabitants are all trying with eqtial steadiness and 
skill to improve their stocks by selection ; the chances 
in this will \h\ strongly in favour of the Kjeat 
holders on the mountains or on tiie plains improving 
their breeds more < uickly than the small holders on 
the intermediate narrow, hilly tract; and con»o<jueutly 



tlif ittipnnp«l TTioiiritiiii or jil.iin hr«f(l will soon fakt; 
till* place of tlio It'ss iiiiproM'd Mil Wrfpd ; and thus* 
the two hroe<tH, whnh uriyiiially existed in cr«»at<-r 
iiumfnTs, will roniH into close cr)r)tact with each other, 
without t)o» intwrpositioii of the HiipplaiitiMl, iriter- 
riiH(ii.ile hill-varit'ty. 

To sum up. I lu'lieve that Hpecio^ come to l»e toler- 
tiiiy wcll-dt'liiifd ohjects, and do not at any one p^Tioi! 
present an cliaos of varsintf and \utf>,: 
mediate links : firstly, hecause new varietie>» are vet . 
slowly formed, fVir variation is a very slow procestJ. 
and natural selection can do nothiti until favourable 
variations chatice to <»ccur, and mail a place in the 
natural p<<lity of the country can l»e U>tter filUxl by 
some mod ideation of some one or m(»re of its itihahit- 
ants. And such new places *ill deftetid on slow 
chang^es of climate, or on the occasional imtni.'ration 
of fii'v* inhahitatits, and, prohaMy, in a still more 
important de^'ree, on some of the old inhahitanta 
he.oinintr slowly modified, with the new frtrms thus 
prxiliired and the old ones actinif and reactinjf on 
each other. So that, iti any one retrion and at any 
otie time, we oujjht <»nly to see a few species pres«»- m^r 
slitrht modifications of structure in some de^re »er- 
maiient ; and this assuredly we do see. 

>ecoudly, areas now continuous must often have 
existe<l within the recent period in isolated portiotis, 
in wlii(h mai.y forms, more esjiecially atnontrst the 
clasM',s which utiite for each birth ami wander much, 
may have se|i.irately U-en rerulered suthcientiv distinct 
to rank as rrprcsentitive species. In this case, inter- 
ni"diate varieties between the several representative 
sjiecie.s and their commoti parent, must formerly have 
e\isteil in each broken jMirtion of t!ie land, but these 
links will }ia\e bijcn supjdanted and exterminated 
duritiK the process of natural selection, .so that they 
will no lontrcr exi«t in a livin;r state. 

ilurdiy, when two or more varieties have been 
formed iti dilTerent p.u-tioiis of a strictly contmuoue 
area, intermeil-ate varieties vrill. it is probable, at fir*t 



bAv»> li»'«M> foriniil ill tin* iiitfrrm li;it»' zoiu's, ' ut tlu'y 
will (jrtMMT.'iUy lia\»* had a ►•hnrl dunitioii. lor flu'se 
iiit»«rmt'(iiMt»> virifi'fs will, frotii rf;i>()ri-. alrt'.nly iis- 
hi;,'iieii (luiiiH'ly trotii wp know (if tho 
liintriliiititm ot fiK-fly allu'ci or rcprrspntative K|HH'it'<, 
aiiil likf\*i.»» uf ;iiknMwU>«ltf»'il vari*!ti«'>), exint in the 
itit»'rrin'«' ZDiitw in lossor ininihiT- tliin the vari<'ti«>fl 
wliirii thi-y irtid to fotiMKrt. From thi.-* caune a! le 
thp iiiit'rm«'fliate vari»'ti»'s will 1)© liahle to accidt'i. il 
•'xtfrrniiatioM ; and (liirin;; tlie process of MirtiuT 
niixtitHation thr<»iii;]i natural >cl«><-ti(i[i, thev will 
aiiiMist fiTtaitily J>e hoaten and >-ij|i|ilant 'd by the 
(■•riiis Hliiih tlu-y «'niiiiect ; for llit -.« from existitii; 
in trrfatt-r luinilirrs will, in tl •• airirn't.,itv , iir»'>4'nt 
ui(ir»* variation, and thus he further itn|in»v««d Inrouch 
ualiiial -»'h'»tion and jr-iin further kdvantat'«'«*. 

l-i>.ily. lo'ikni;: n(»t to any one lime, 'ut to all time, 
it my fiifory Ite true, niiniherle>s interiiudiate varieties, 
linki!!.: niiist rlo^ely all the Kpecies of the same croup 
toiTi'tiicr, miivt a^-iiredly have existed ; hut the very 
>ro.f»s of natural <elerli(>u co!i>tantly tends, as h;is 
>een so <»t"len remarked, to exterminate tlie parent- 
tornis and tlio intermediate links. ( <nise<iuently e\ i- 
ilence of their luriner exi-iteine could be found onlv 
amHi:jr>t fo>i>il remains, which are preserved, as we 
xhall in a future cliapter attempt to ^iiow, iu an 
extrcMifly imjK'rfe« t and intermittent reror<i. 

"ii thf (,riii\)i and trtnuitioitu of org inic hfingn uith 
fiiilinr hnhits iind atructure. — It has been a.sked by the 
('iiponents of such views as I liold, liow, for iusLanre, a 
land carnivorous animal c«)uld ha\e been converted 
into one with aijuatic hahit-s ; for how coulil the animal 
HI its tran-itional ^tate have subsisted? It would be 
c\Lvy to sliow thiit within the same gT<n][» «-arnivorou!« 
animals exist havintr every intermediate ;rrade between 
truly aijuatic an<l ^tril•tly terrestrial habits ; and as 
each exi~t.s by a strujrifle for life, it is dear that ea«h is 
well adajiied in it- habit,s to its place in natu'-e. l/iok 
at the Mustela visou of North America, whicJi luw 



welilioil r»>»*t .iihI wliich r»•^«'rnf^lo^ nti ott»»r in itit fur, 
!<li()rt \*'HH, .triii foriM o^ t;til ; iluriii/ sutniru'r thi^ 
.iiiini.'il (live-^ for and proy* on fisfi, l»iil (liiriiiir the Umg 
w'litcr it leaves th»* fro/iMi w.-iti'M, .inil nrt'vx like (»fhor 

IM(l(»-c;itM on tiiitH and l.ui-l nnlrnti-. If a (iitfi'rent r.xs»« iM't'ii tiketi. ami it ]\:ui h»MMi :i«k«Ml how an imej'ti 
vontus <|ii;niriij»«M| could po«ihlv h.iv»» hi'cri convj'rted 
into ;i tiyiiii; hat, the i|ii««stion would ha\(> hpcn far 
riiori' ditfii lilt, and I could have ;:i\i'n no aii^wpr. V»it 
I think such difhculties h.ivo very little wfiaht. 

Hero, ax on other o< < a'^iotH, I lie under a heavy dis- 
ad\ant-ii:»>, («»r out of tho many strikiiijf ia>es which 1 
have collected, | can ifive only one or two i'l^t.-ince^^ 
of transitional liaMt>< and structures in chwelv allie«l 
specie-* of the -ame yen us ; and of diversified habits, 
either consfuif ctr occasional, in the same species. And 
it cems to trie that rn»thint' h"*"* than a loin; list of such 
cases is suflicient ti» lessen the diMii ulty in any par- 
ticular «'ase like that of the hat. 

L>ok at the family of sijiiirrels ; here we have the 
tine-t eridation from animals with their tails only 
slightly flattened, and from others, as Sir .'. Kichanlson 
iias remarkeil, with the posterior part of their Utdies 
rather wide and with the skin on their tianks ratlier 
full, to the >;o-caIled tlyinjr sijuirreU ; p.nd lUinjf 
squirnds have their limhs and even the iia.-e ef the tail 
united hy a hroad expanse of skin, which serves a.s a 
parachute and allows them to jrlide throujrh the air to 
an astonishiiiir distance from tree to tree. We cannot 
douiit that each structure is of use to e.ich kind of 
sijiiirrel in its own country, hy enahliiiL' it to esca})« 
iiirds or heats of prey, or tocoilei't toinl more <|uicklv, 
or, art there is reisori to helieve, hy lesseninir the 
dani^er fr<«in occasional falls. IJut it does not f<d!ow 
from this fact that the structure of each stjuirrel is the 
hest that it is possible to conceive under all natural 
condition.s. Let the climate and veiretation chanjfe, 
iel other competitu; rodenUs or new tveasts of prey 
imrrugrate, or old ones become modified, and all 
aualofry ^ould lead us to ttelieve that some at lea:>t ol 




thi' -.iniirri'l"* wniilii (ii'irea*** in minilnTii or iMToriii* 
»' vt»>«<<l, uii!f-.>4 tln'v al-») lu'raim* nunlitu"il .. kI 
m;|iri»\««i| in «trin tiir»» iii .» rorri'^tpoiuliri^ tnniiiicr. 
riiirefnre, I iviii •>♦•<• nn iliflii iilly, more e«|>«'ti;illv 
ninl«'r i'lir»n;:iiiLr ' umlitioiia of lifp, in flip fiMitimn-'l 
|>'-i-<Tv;iti<in of inrliviii'ials witli IuIUt and fiiII«T llank- 
'luTiilir.'iii*'-, i-arh modification hoin^ iixpfiil, rarh lipint' 
jtrnpac'i''''. until l-y th»» arcnmiilativl ♦•rffct^ of thu 
|iriMt'«i- of natural >rl»'rti()ii, a jM-rfett i*(>-rallt'd flyin;j 
Htj'iirrfl ".■i> prfxluiod. 

Now look at the (JaU'ojtithecim or thin:,' lemur, 
*h'ili fortrifrly w.t« faUoly ranked atnonirst }iat>. If 
li.iH an exfrt'ini'ly wide flank -rnfmhrane, strotcliinj^ 
fr(ir?\ tlie forner"* ot tlio Jaw to tlie ta:l, and including 
the IifmIh atid tlie eli-iiL'^ted fintrers : the flank-nieni- 
hriim ;•*, also, f'urnisheii witli an extensor niiiscle 
AltlioiiL'h ii't ;,'radiiatod links of .structure, fitted for 
u'lidinj: fliroii;;li the air. now connect the («aleo[iitht'cu« 
«ith th" other I.cinuriila*, yet i see no dill'Multv in 
sii;«|i(i>;nu' mull links formerly exiftted, and that 
eaili had '■•■.■n formed hy the s.-inie -tejH as in the case 
of rlio !'■-' |ifrtV( tly trliijintr s«ji;irrels ; aiul th ii each 
trrade of strurture uas useful to its jios>essor. Nor 
can 1 see an? ifisujicrahle ciifliculty in further l)e!ievinL' 
if possible that tiie meinlirane-connected fin^er.-i and 
tore -arm of the ( ialconilhecus mitrht he jfreally 
leii.:tht'ned hy nafiiral selection; and this, as far a^ 
the (iriTaiirt of flij.'^ht are concerned, wouM convert it 
into a l>at. In hats which have the win^r.niernhrane 
extended from tlie top of the shoulder to the till, 
incliidirifr the hind-le;rs, we perhaps see trai-es of an 
apjiaratus oriLritially cot.»tructed for plidiiur throuch 
tie air rather than for fii;:ht. 

If ah«Mjt a do/eu ^renera of hirds had hecome extinct 
or were unknctwn, who wouM have ventured to have 
surmised that hirds mitrht have existed which u>eil 
their winir« solely :ih 'l.-ipiter^, like the lr-=r-;?r-h?'ridei' 
du.k (Micropterus of Kyton) ; as tins in the water and 
front le^ on the land, like the j^eny-uin ; as sails, lik 

the outrirh ; and functionally for 

no purpo>-e, like the 




Aptpryx. \iA tlie structure of cacli of these Itirds is 
trooil f(»r it, uiidor tlin c(»iiilitioii!> of life to which it 
is exposrcl, for i;;i(h t;> live by a •■truiririe ; hut it in 
lint iifcr».;irily the i>e-l jtio-ihle u!n!"r all piw-ihle con- 
diHoii^. It must not \,k inferred from tlit'>»' reni.irks 
thiit any of tiie tjr.i<l('s of win;::-structiire hero alhided 
t(». wli;i li perhaps riia\ ail have rt'-iiited from disuse, 
iiidnaii- the ii.iliiral steps iiv w hich l)irds have aeijuired 
tiieir perfect jiower nf lii::lit ; hut thev serve, ;it 
lea^t, to show what di\ er>iti('(i riieaiis of traii>itiun are 
I n.h-. 

>eeiii:r that a leA- nienihers of such water-l'reainiii^ 
cl.i-se-> as the ( rusttcea aini Mollu-ca are adapted to 
live oil the laii 1 ; and seeing that we lia\e flyinir hirdu 
and iiiaiiiriiaU. liyiii;^ injects of tlie most diversiiied 
t\|'ev. .iiiii foriiierlv had tlyiiiir reptiles, it i^ con- 
ceiv.ihle tliat llyii:_ n>h, which now trlido far tiirMii;:h 
the air, sii^ihtly n-iiir and turnini: l»y tlie aiil of tiieir 
flutteriui: li'i-;, ini:,''J hav.- Keen iiHidi;ifd into perfectly 
'»in:red animals. It this lia<i tweii ejfected, who would 
iiave e\iT ima^^incd that in an early iraiisifiniial stiite 
'!ie\ liad ln'cn ii:liatiitaiits of the oj)t'ii ocean, and 
h id u-ed their incipriit or^'ans of ihirhl e\^lu-i\eh-, as 
:ar as we know, to I'srape l)einL'' devnured hy uther 

W hen we «ec any structure hitrhly pejtected for anv 
particuhtr hahit, jis the winjrs of a hud tor llitrht, we 
shoulij dear in mind tliif animals disidayiiitf early 
t raiisitional trrades ot" the -tructure will st-ldnm continue 
!•■ e\wt to the prevtMit day, for they will !ta\e heen 
supplanted hy the \er\ process of perfection throutrh 
natur;il -eloctiori. |-"urthermore, we may comlude that 
transitional L'r.ide- 'leiwcen structures titted for verv 
different iialn's of lil'e will rarelv lii\e h«'en deselopeii 
ai an e^irly period in i^reat nunil>er> and under main 
suhordinatt' !orm-. Thus, to return to '• ir imairitiary 
illustratiiui of the tlyintr-tish, it does not seem pridalile 

t li li^'^e-. ctji.iiii*' oi Iruo ii:;^ilL Hiiiiid iiave iu'eu 

d"\e.(ij.. i uruicr many siilMirdinate turiii*, for takiny 
prey uf niany inids m many ways. r)ii the lam! and in 

DIFFK ri/riKS f)N •mE( 


t\.(^ water, until tiif'ir orc"aii« of flight i . -ome to a 
li .:li staire of {K-rfeetioii. so as to have ffi. ii tlioin n 
(l«'t iui.^! :i<iv;intaL''t' over ntlior animals in tin' l>attle of 
lilt". ll«Mi(e th«' clianre of (li-toveriiitr sjk'cIi's with 
transitional irradi's of Htrtn-turo in a fossil oomlition 
will ,ilvva\< Iw less, from their havinir existed in lev>.pr 
uiimKtTs. than in tho ('ase of pjM'cies with fully ileM'loj»c<i 

1 «ill now ;.rivi' t'.vo or ihrvP in-tani-e** of (ii\»'rsifnMi 
and of ch.iiiv'^t'd hallit^ in the individuals of the same 
specie- W hen either case occurs, it would i>e ea«y for 
natural selecti<Mi to fit the animal, by ~ome tiioditication 
of its >tructure, for its «hanired hal'i;-, or exclusively 
tor one of its several different hahit-. Mut it is difficult 
to tell, and immaterial tor u<, whetiu-r habit'* frenerall, 
chaiiL'e first and structure afterwards ; or wlH'thcr 
^liffiit ifuxlitications of structure lead to chantred liahit^; 
both [>rohaMy otleii chanije almost simultaneously. 
« "r cases of clian^ed haltits it will suffice merely to 
iliude to that of the many Hriti-h insects which now 
tVed (in exotic plants, or exclusively on 
suhstTiiceH. ()f diversified habits imiumerahle instances 
cnuhl he g-iven : I have often watched a tyrant fly- 
catcher i Saurojihairus sulphuratus) in South America, 
hovering over one spot and then proceeding to another, 
like a kestrel, and at other times slandinj; stationary 
on the mar^^in of water, and then dashinti' like a kmjf- 
tisher at a tish. In our own country the larirer 
tittuouse (I'arus major) may he seen climbing' branches, 
almost like a creeper ; it often, like a shrike, kills small 
lijrds bv hlf»ws on the head , and I h;t\e tnan\ times 
-.t"*-!! anil heard it hammerinff the seeds of the yew on 
» h, and thus hreakiinr them like a nuthaUh. 
hi North America the black bear was seen bv lieariie 
sw nimifi^' for hours ..ith wiilely «ipen mouth, thus 
i-a'chmtr, almost like a whale, insects in tlie water. 

.\.s we son'etimes see indiviilual.s of a sj.ecies follow ini; 
ha'iits wideiy tiiiiereut irom those oi liieir own sperie- 
anil of the other spi-cies of the same penus. we mi^ht 
expect, on mv Mieory, that "^uch individual? wciuid 




oc«asionally liave jfiven rise to now KjHjcie*, haviiij{ 
anonialotJH }i;i!tits, and witli tbcir structure either 
slifflitly or considerably in(Mlifie<I from that of tlu'ir 
proj»«>r type. And such instanien do occur iu nature. 
-an a niore strikinjr insLince of adaptation l»e trivon 
than that of a woodpecker for dinihinj^ trees and tor 
•^ciziiifj inserts in the chinks of the Iwrk r \ei ni .North 
.America tliere are wtwidpcckers which feed laruely on 
fruit, and others with eiorifated win^-s whidi cfia«.e 
iiiM'cts on tlie. wintr ; anil on the plains o! 1^ I'lafi, 
whi-ienot a tree throws, tliere is a woudfiecker, whi.h 
III every essential part of ilH orpanisiition, even in it,; 
ruloiirin^r, in tiie tone of \U voice, and unduiatorv 
lii^'hl, t(dil nie plainly of its close blood-relatioiiship 
to oiirnimriion speci.'s ; yet it i- a woo«lpc(k»T which 
ficvc ciimix. a t.ree ' 

J'rtreis ar.- '.he ino>t aerial and t)ceanic ot inni-, vet 
in tlie .|uiel Sounds of 'I'ierra del I'r >^o, the INidinuria, in its peneral habit,s, in its a.stonishi ^ po«cr 
<.t diviiifr, its ni.iii .■>• of rtwimminr, and of liyuifr w lien 
uiiwillinjfly it Ukt.^ <l:j;ht, would he mistak'en l.y any 
one fur an auk or irrehe ; nevertheless, it is essen'tiaiiy 

• jietrel, hiil with many parts of its ortfanisatiou pru- 
loundiy modified. » )n the other hami. the acutest 

■ '•server l.y examining: the dead liody of the water-ou/el 

• Mild never have susi)ected its «uh-aquatic iiahits ; yet 

ihis anomalous member of the strictly terrestrial thni-h 

'aniily wholly subsists by divin^r^—pVaspine llie stones 

with its feet and usin;j its wintjs under na'i r. 

fie who believes that each beiuic has Wen created as 
we now see it, must occasionally ha\e feit surprise 

• •hen ho ha.s met with an anunal haviiii; iial»itj» and 
structure not at all in .i^reement. \\"ti:a can be 
p' iinor than that, the webbed feet ot duck- and eee^e 
ure formed for sw miminff .-■ yet tliere are upland ^ei'-,e 
»'. itii welilted feet which rarely (sr never po ne;ir the 
^'■ater; and no one excejit Audubon has seen the 

us lour itM'S nciMieii, Miij^iii 

a.s ait 

»■_;,...»,, 1 :„ 1 ,, I 

on the surface of the sea. On the other hand kJcIk'h 
and cent . are eminently aipiatic. altliMU^rl, their toe» 




are only Jwrderod h\ nu-mlmme. U'liat Kt-enis plainer 
than that the li.nir toes ot ^r«llatores are Jornied for 
v»alk;nsf over swamps and lloatinir plants, yet the 
water-hen i< nearly bh aijiiatie a:- the ««»nt ; and tlie 
landrail nearly as terrestrial as the (jiiail or ji.ii tridtre. 
In Biicb cH-es. anil n>any other- .oiild l>e tfi\en, hahilM 
have cliaiif:e<l without a correspond ititi chancre <'f 
strurture. The wehl-ed feet of the upiand jfoose may 
he (iaid to have l»ecome rndiinenlary in function, 
ihouL'h not in Htrurture. In the friirate-hird, the 
1» deeply-stooped nienihrane hetween the toe«* shows that 
structure l.ctrun to chanu'^e. 

lie wlio Itelieves iu separate and innunierahlc acts of 
cre.-itK.n will say, that in the-e cases it has picked the 
Creator to «ause a hein^ of one type to take tlie place 
o'" one of another type; hut this seems to me only 
re-statititr the t:ict in difrnified lant;ii.i{re. He wlio 
helieves m the -tru;rtrle f.»r existence and in tlie 
principle of r.atijral selection, will acknowledge that 
everv oriranic heinj; is (onstaiitly endea\ounn:r to 
increase in numhers ; and that if any one heinjr vary 
e\er so little, either in liahits or structure, and thus 
eain an advantage over some other inhahitant of llie 
c<»untry, it will sei/.e on the place of that inhahitant. 
however diiterent it may l)e from its own place. Hence 
it will cau>e him uo surprise that there should he 
^ree^•o and frijfate-birds with wehU'd feet, liviji;; o-i the 
dry land or most ra:fiy alitjhtintr on the water ; that 
there should be lontc-tood corncrakes li\ injf in mead(»ws 
inste-ad of in swantps; that tiiero should h«- wood- 
jK-ckers where not a tree t'rows ; tliat there should he 
divinp thrushes, and petrels with the hahits of auks. 

Orgtius ot extreme pfrjWtwn ana contpliaition. — 'lo 
suppose that the eye, with all its illimitable contriv- 
ances for adjustintr the focus to ditTereiit distan<es, lor 
adTnittmu different amount; of light, and for the 
coiieilioii or pptifruai and <-i:ru!::a.2: a.:-e.ia-.iOU, t •><.;«, 
have i>een formed hy natural selection, seems, I freely 
confesv. absurd in the h'.jfhest possible decree. Vf. 




r&'ison tells rne, if iiurntTnii-i LTad.-itiotis Irorn a 
porfoct and complex eye to one \v:y iin|M'rt»'. t ami 
siniplo, each (irailo ln'iiit' ii'^i'tul to it-, pi !*>»•->.(, r, can 
!)♦• slinwrj to c\i>t ; if furtii.T. tin- ey«> Huck vary 
v\OT SO slitrlitly, and tli.- variatmiis I-m inlieritcti', 
nhich is certainly tlic i i>c ; and if anv \ariation or 
nmdifjcation in the or;:an 'i>e evt'r ii'.etui to an anim.'.l 
under cliaiiL'-iiiir <'oniliti(.ns nf lite, tlicn ti.e diilicnltv 
of helievintr that a i»er!ect and corii|)lex e\e could bo 
tornied \>y natural selection, thoiiL'ii in-.u|ierahle by 
our iriiariii'ition, can hardlv lie con-u'ered real. How 
a ner\e cunies to he -en»iti\e to li;:ht, hanllv cuncerns 
tjs riior(! than how life itstdf tirst ori;,'-inated ; h>ut I may 
remark that s»'vcral facts mai<e mc suspect that any 
sensiti\e nerve may he rendered sensitive to lij-ht, and 
likewise to those coar-er vihratioim of the air u!:;ch 
proiluce sound. 

In hinkirii,' for tlie ^rradatioris hy whi-li an oriran in 
any sjieciis has heen perfected, we oiiji-ht to look 
e.\.lii>ively to its lineal ancestors; l»ut this is -carcely 
e\er possible, and we are forceil in each <ase to look to 
species of the K.aino frniup, that is to the collateral 
'iescendants from the same oriLMnal narent-f(»rTn, in 
order to see what t:radations are possilile, and for the 
< hance of some trradations lia\in<f heen transmitted 
tioiii the earlier staires of descent, in an unalfer«'d or 
little .litered condition. AmonL^>t e-xistiriir \'ert»'hrata, 
we find hut a small amount of ;,'-radation in the 
stru( tiire of the eye. and tr(»m fossil species we can 
Ifarn nothini.'- on tin- iieail. In this ^-^ cla.s.s w© 
should pnd.ahly have to descend far heneath the 
li'west known fo-sihleroiis stratum to discover the 
• .iflicr staire-. hv which he eye has heen perf. cted 

!n the ArticuiatA we can commence a series with an 
optic nerve merely coated with pi^rment, and without 
any other ; and Irom this lnw staire, 
nnmerous trradations of striiciure, iiranciniitr otf in two 

.... I . » I 1 .. 1 .1- . !• _ . I 

:-.i;. •:.:;:;;::;-;; ;y ;;;;;crc:;i iinCS, i.'iu iiC Siiurt u In e.visL. 

unL.l we reach a in»>derately hi^jh stiijre of perfcctiua. 
In .ertain crustaceans, fur instance, there is a double 

m .' ' 




roriK'n the inner one diviileil into fa»\ts, within earh 
of which there is a leim-«haj»etl f!w»-iliinf. lit otlier 
crustareans t'lc tran«i'.irent « oiiex whi< li are rf>,ae<l l>y 
T)!:.Mii«'iit, iiiii: »hif)i projierly ;i(t onlv by exilmiini; 
Literal p«'ririU of'hirht, are convex at their ii[>|M'r euii* 
and must act tiv ((invprt^crice ; ami at tlieir hmer • :iiir4 
there seems to he an irnperfecf vit .ous suhstauce. 
^^ ilh these fails, here far to«. hrietly aiui inijn feitlv 
triven, wliich -^liow that th^re is much i:raiiuate<i iii\er 
sity in tJie eyes of liviiiir irustareaiiH, ami hearing' ni 
niind h«>vf small the niiinher of Irintf a'lirnals is si; 
pro{>nrt:on to those which have heconi*' ex .net, I ••an 
see no \»*r\ trrt-at difTicultv (not more ' an in the case 
of many other stnirture't in helievinar that n.. iira 
seieciion lias converted th«« < pie app.fatus of an 
optic nerve merely coated with j lament and invested 
h\ transparent menihrane, into an op 'al instrument 
a- perfect a- in pos!>es»ed by any menil)er of the jfreat 
Articulate ilass. 

lie who will tfo thus far, if he '"nd on tinisliin-r thi"* 
treatise that larire bodies of fact.-, otlierwise inexplic- 
atile, can he explained by the theory of descent, ought 
not to hesitate to go further, and to admit that a 
structure even as perfect as the eye of an eaule niitrht 
Ite forme<l hy natural selection, although in this caso 
lit? does not know any of tin- transitional tfrades. His 
reason ouirht to cornjiier his nia;rii»ation ; thou>;h I 
have felt the difficulty far too keenly to i»e su'-]irised 
at any detrree of hesitation in extendinir the pnu'-iplp 
of natural selection to such st.irtlinu leiiifthH. 

It is --carcelv possible U) aM'id comparing th»» eye to 
a telescope. We km-w that this instrument h.i> l)een 
perfeited by the lontr-eontirnied etforta of ih<* liijfhest 
M.iman intelleets ; and we naturallv infer that tlie eye 
has been funned by a somewhat analogous process. 
5'"Ut may n«it this inference J>e presumptuous.^ Have 
« ' any riirht to assume tliat tfie ( reator works by 
1 uTr-iiect (i<ii ponrei!* iiKe Uio^e oi man.' il nt* iimst 

compare the eye to an optical instrument, we oLirtit iu 
in\at;ihatii>n to tal^e a thick layer of tran.sparent tissue, 






•AJth a nerve ueiiKitivc to lijfht Ix-utath, and then 8uj»- 
p<)sp every part of thi> layer to bo continually chanjriiig 
nlovvly in density, so as to Keparate into layern of diricr- 
eiit densitit-- and thicknesses, nl.iced at dilfcrent «lis- 
tanccH from each other, and with tlie surfaces of each 
lajer slowly chantrintr in luriii. Further we must sup- 
pose tliat there is a power always intently watching 
each sli;,'ht accidental alteration in the iransj^rcnt 
layers; and carefully -cU'ctinp: ea»Oi albTation wiii.h. 
under vancd circumsLince^. may in anv ^ay, or in anv 
df;rre«', tend to produce a distincter irii,';;e. \\ v mu.-t 
Huptio-.' each new stite of the instrument to h*' 
inultiphcd hy the million; and each to lie prc^-erved 
till a Ijt tier he produced, and then the old unes to he 
d»ixtr.(yed. In livinjf hodies, variation u.'l cause the 
sligiit alterations, peueralion will inullijdy tliem almost 
intiintely, and natural selection will pick out with 
unerrin-; skill each improvement. U-t this j)r()ces> uo 
on lor millions on millions of years; and during' each 
year or; millirjiis of individuals of many kinds; and 
may we not helieve that a livijiff optical instruineiit 
m ^lit thus ho formed as superior to one of ::lass, as tliC 
works ot the ( reator are to those of man r 

It it could he diinonstrated that any comjdex or^^-^an 
existed, which could not possibly have lifcn formed hy 
numerouij, successive, sli;rl,t modifications, my theory 
would al)s()lutely break down. Hut J can find out nii 
such case. No doubt many organs of which we 
do not know the transitional gradeti, more especially ii 
\se look to much-i>olated species, round which, acct)rd- 
intr to my tlu'ory, there has been much extinction. Or 
liiam, if we look to an orirau common to all 'he mem- 
•t-rs of a large class, for in this latter the organ 
must have been tirst formed at an extremelv remote 
period, since which all the many members of the cla-s 
h.i\e heen developed; and in order to discover tlie 

e.irly transitional gra.les through which the organ has 
.„ I.. 1, — 111 . 1 1. 

J .1 ., n; ^.:uliiu iitl>U lU iOOK tO '»erj uiiiiCiiL iiin e^llui 

tornis, loii^ since become extinct. 

^^ e should be extremely cautious in condudinif that 




■la orpaii could not have bet'ii formed liy transitiotiai 
grad.itioua of Kome kind. Numerous ca'<i^ could l>e 
irivou amoiiL'^'t tlio lower animals of the same or(;.tii 
performintr at the Kaine time wholly distinrt fun«"tions ; 
thus th<' alimentary canal respircH, digests, and excret**** 
in the larva of the dragon-fly and in the lish Cohite-.. 
In till' Hydra, the animal may he turned inside out, 
and the exterior purface will then dni^est and tiio 
Htoriia* h rt'-jtire. lu such cast-s natural eflection niii»-ht 
e<4sil\ specialise, if any advantage were thus ^--aiind, a 
part or oriran, which had performeil two function-, lor 
one function alone, and thus wholly chanjje its natu!»« 
hy iii-ensihle stt'ps. Two distinct ortrans gometim*'-* 
perform simultaneously the same function iu tlic sari..! 
individual ; to tive one instance, there are fish with 
jills or hranchi* that hreathe the air dissolved iu tlie 
water, at the sarue time that they hreatho free air iu 
:heir swimhUdders, this latter or^^n liavin^ a durtus 
pMcuniaticus for its Bupply, and hein^ divided hy highly 
vast ular partitions. In these ca-es one of the two 
or(^aiis mifi^ht with ease he modified and perfected so as 
to perform all the work hy itself, heing aided durnur 
tlie procft's of modification by tin* other or^au ; and 
then this other or^ran mijfht l*ti mo<lified for some othtr 
and (juite <li-tinct purpose, or 1k3 unite obliterated. 

Ilie illustration of the swimbladder iu fishes is ,» 
^ood one, In^cause it shows us clearly the hitrhiv 
important fact that an orfjan orijfinaily con.-trui-ted for 
one purpose, namely flotation, may Ihj converted into 
one for a wholly different purjK)se, namely respiration 
'Hie swimbladder has, also, been worked in a-s &ii 
accis>;ory to the auditory org^ans of certain f'sh, or, for 
1 do not know which view m now ^enera'ly held, a 
part of the auditory apparatus has been worke<l in as a 
complement to the swimidadder. All ph\ siolo^^ist- 
admit that the sw imhladder is hcinoloyous, or * ideally 
eimihir' in position and structure with the luric>* 
ot the higlier vertebrate annuals : heiue tliero 
st'cms to me to be no frreat ditTu ulty iu beLe' - 
ing that natural selection has actually convertei! a 




BwiTTiMadder iritu a luri^, or ortraii n^» .1 oxclusively for 

1 ran, iiidppd, liirdly doiifit that all vortrf.rate 
animals h.Hv;ii;r trim liiriir'^ liave dr^^cciidcd l>y oniiii.iry 
fi'iifratitin from an anrieiit protntypo, of wlii< li we 
kimw nntliiiiir, fiiriiislu'd nitli a tlo.itiiiir af)|>ar-itiis or 
■.wirnlilaildcr. \\'»» cin \h\i<. an I infer ;r<>m I'rdfevsor 
Ov»fu H ir.tfrostin:; di'scription (»f tlie-o parts, iinder- 
Ktiind the >«trai!u'e fart tliat every particle of fofxi and 
drink which we '•waUow has to p.i>,-s o\er the i<ritice 
of t!ie trache.i, with .■>onie ri-k of fallintr into the I'li^'s, 
Motvntlivt iiidni^' the hea;itifiil roiitrivanre \>\ which 
the trl'iilis is clcised. In tlie hitrher \'ertel.rata the 
'iraiK hiii" have wholly ilisa|)p»'ared the slif.a on the 

wi.-* of t)u« neck and the loop like course of the 
arteries -till markini: in the enihryo their former posi- 
tion. I'.ut it is coiicei\aMe that the now utterly lost 
hranch .H mijrht have lieen trradually worked in hy 
•satiirai sdec tiori for some quite distitict purpose : \n 
•he <itiie manner as, on the view entertained hy some 
i:aturalisLs that the hranchiie and dorsal scales of Anne- 
l.ds are homolotrous with the winp* and win^-covers of 
inse<ts, it is prohahle organs which at a ■. ery 
aM.ient period served for n-piration have heen actually 
converted into ortrans of flitrht 

!n consideriiifr transition-s of orp-ans, it is -o imjiortimt 

' iie^ir in mind tlie {irohahility of coiuersion from one 
tiinclion to another, that I Mill ^rive one more instance, 
redui.cuhited ciirijierles have two minute folds of skin, 
• ailed hy me the ovJi^erous frena, which serve, through 
the means of a sti( ky secretion, to retain the etrtrs until 
•he;, are h.itt hi'd within tlie sack, 'ihose (impedes no hraiit ).iji», the whole surface of the houy and 
sack, iiicludinif the small frena, serv in jr for respiration. 
Die I'.aianida' or sessile cirrijiedes, on the other hand. 
In •' no o\iirt'rt»us frena, t};e efrtr* lyinsr loose at the 
h,)ttoin of the sack, in the well enclosed shell: hut 
wiii y . .r. ,■ i,,r :€■ loMleii oiainiii*t«. iVow i Liiiiik no one 
will di-jiute that the ovi^-erous frena in the one family 
^r« struily hoUHilo^rou;! with the hrauchm" of the other 



f.imilv ; imlfvil. tlu'v ♦rnulii.ite ititofaili nllifr. Tlier**- 
lore I (!i) nut doultt that little foliN of -kin, «liicJi 
oritrinallv '*»'r\e»l as ovict'rou-* frt'n.i, l»iit which, like- 
wii4«», verv >li;:htly ai(l«vl tin* ;ict of rt'spinition, have 
\<t^'n iir:id\i:i\ly convfrttul l»y n.ilural ^^'i»•« lion into 
hrH!ir> lit*, sHiiiily tlirou^rh an increase in their si/e atut 
the iiKKteratidii of tlu'ir aiUiesive fjiainU. It :ili peii 
unculatt'd cirri[)«Mifts ha'i t«ecome extinct, ami tlie\ 
ha\e already suffered lar lunre exlinction than lia\t» 
ses*i!e cirrijiedes, who wduld e\er have imairined thai 
the hraiHliiir in this latter family liad or!j;inally existed 
as ortrir;-; (or jireveiitiiijf the ova from lieiii;; w.ixh<'<) 
out (it tlie '•ark r 

Althoiiirli we must 1)« extremely cautious in con- 
cliniiuL' that any t»ri;an could liol possihly h.i.e l^eii 
produced by successive tran-ilioiial irradations, vet, un- 
<ioul'tedly, irrave ca.>»es of difliculty occur, some oi which 
will l>e di<cu>sed in my future work. 

('lie of the 4rra\e^t is that of neuter injects, which 
are ott»'n \ery differently constnjcte<i from either the 
mah's or fertile females ; hut this case will \xf treated 
of in the next chapter. The electric or^'ans of fi-«hc» 
offer another case of <[)ecial difficulty ; it is imp<»sililf 
to conceive hy what step-; these wondrous or;rans have 
hee:; produiH'd ; hut, a- ( >v\fn and others have re- 
marked, their intimate .-tructure closely resemhies that 
of I'ommoii nuKcle ; and as it has lately In-en shown 
that Kays have an or;ran closely analoic'uis to the 
electric aj^paratu-, and yet do not, as Mattcucei asserts, 
di >cliHr«^e any eh ctricity, we must own tiiat we are far 
ti>ti itrnoraiit to ar^ue that no transition of any kind is 

1 he ele'tric ort^ans offer another and cM-n tiiore 
serious diiliculty ; for they occur in only about a do.-en 
(i^lifs, of which ^e\eral are widely remote in their 
affinities, iienerally when tiie s;ime orjran appear- in 
several memf)ers of the -ame class, estH'cially if iu 
meiiihers having very different hahils of life, we may 
attriliute its iiresence U> iniieritance from a tommon 
ancestor ; and it^j ah>ence in -oiiie of the tnemhers lo 

! <s 




its l(Kn tlimiiirli ilisij"i»> or nrituml ■itlccliori. Mut if the 
olcctric orff.uis hud Ihtii intifritnl from ciiio amit'nt 
prD^-i'riitor thus pnu idfd, we niiirht li.ive cxii.-t tt'd that 
all »'lt'i'tric f"i-lM"s Willi III lia\«< heeii spi'ri.iHv r<'!at»'d to 
iTicli otlicr. Nor dnr-i (.noloirv at .ill liail to tli»' lu'lief 
tiiat toriMcrly nio-t li>lifs fifi trie urt:iii>. whirh 
nuwt of tlM-ir irutdilu'd df-n-iHlaiit-^ have lo«f. Hh' 
pri'S«'ii(i' of lumiiioiH ortjaiM in a fi-w ir)«-('(t«<, hflnnir. 
iiitf to ditfi'r»'nl faniilifs and orders, otTi-ri a [laralh-l 
ca-i- of ditlii iilty. < UinT rases could he Lriveii; for 
iiistaiico in iilaiit-^, the very eurioiis (•oiitri\ arne of a 
ma-* of ptdlcn-tTaitis, honie on a foot stalk with a 
wtii ky irlaiid at tlie end, is the same in ( )i ■ liis and 
A'clfpias. :^eiieiM almost as remote as possilde atiioiit;>,t 
l^twerini: plants. In all these cases of two verv distinet 
sperii's furnislied with apparently the -ame anomaioiis 
o;^ran. it shouM he oli-tTved that, althoutrh tlie ijeneral 
appearance and function of the or^'an mav lie the same, 
yet some fundamental ditference can trenerallv he de- 
tected. I am ificlined to lielieve that itJ ncarlv tlie 
-ame way .as two men ha\e -ometimes indt penilentlv 
hit on the very s,ime invention, so natural selection, 
working' f'>r tlie irood of each heint^ ami taking: advaii- 
ta^'e (if analoirous variations, has som'-times modified 
in very nearly the same manner two parts in two 
oriranic hein^'-, wliicli hfin^rs owe hut I;itlt' of their 
^t^Ultu^e in common to inheritance from the -ame 

Althmitrli in many cases it is most difficult to con- 
jei'lure hy what traii-Itions ortrans could have arrived 
at their prc-ent state ; yet, coiwiderinir that the pro- 
{M>rtioii of liviii'j- and known forms to the extinct and 
unknown is very small, 1 have heet) astoni-hcd how 
rarely ,an orran vnii he named, towards whii'li no tran- 
sitioiial irrade is known to lead. I'lie truth of thi- 
remark is indeed sliown hy that ohi hut somewhat 
exa^rircrated c^non in natural liistory of * Natura non 
facit sallum.' We meet with this admis^iion in the 
writiiiiTM of almost every oxperienced naturalist; or, 
as Milne K/<1 wards has well e.xpre«««(-d it. Nature is 



!)IFH( I i;riK.s ON TIIKOHV 

175 iti variety, Imt iii::s.':inl in iiinovafidii. \V\i\-, 
• •n th« theory of Creation, nhouid thin U* so' Why 
'hoihl all th«» parts atul nr^'atis of tunny iii<l.|H'inlfiit 
h' /iiiT-', eath >;ii|i|)(>«*oil to have ]>vvn «»'{iarat»>lv rn-alctl 
f'T its proper plarc in nature, he so eomrnonly linked 
liiu'other hy jrradu.ited steps? Why hhouhi not'ire 
have tak.-n a h'ap from «itrJi('tiire to struet iiro .' On 
'he theory of natural srlection, we «'an eleariy iimler- 
-» itid vthv she sh(»i]!(l not ; for n.-ttnral s«-let iion ran 
3' t only hy takinij a<lvantatre of >h^ht stice* -yive varia- 
tions ; ^h.' ean nev»T take a leap, hut must ailvance !>> 
the sliiirte^t and sh)v\c>it stepi. 

'ir>j'in.<i of I'lttlf iifijmrfiit irufiortmire. — A» natural 
M-h'ciiiin a<-U hy life and death, -hv the jnewcrvation 
of individuals v^ith any fa\«»urahle variati-ii-, and hy the 
de>tniction of those with any unfavourahle deviation of 
strii.'ture, - 1 have sumelimes felt muih diffuMilty iu 
iinderstandiiiL' the ori;;in of nimple parts, of which the 
iiMporfance d(f<-i not seem sufllcient to rauso tlie pre- 
servation of suciessively varyinjf individuals. ! have 
sometimes felt as mueh diHieulty, though of a very 
fiitfiTfiit kind, on this head, as in'the easf of an orirari 
1- pi rtc. t and comjilex as the eve. 

In ih.- Iif't place, we are much too i^-imrant in re^rard 
lo the whole economy of any o>ie orjjanic heiii;;, to say 
what slij^dit nKKliticatiotis would Ite of importance or 
not. In a former chapter I hav«; jfivon instances of 
most triiliiii.' characters, mi,h as the down on fruit and 
the rohwir of its ih-sh, which, from determininj; the 
attacks of in-ect-s or from heinjf correlated with con- di;icrences, mitiit assuredly he acted r,n by 
natural selection. 'Hie tail of the jriraff,. |o„ks like aii 
«rf;ficKil!y constructed !!y-f1apper ; and it sfj'uis at first 
iiicri-dihle that this could have l»e(«n a<iai»te<l for its 
prevent purpose hy succes,>i'. e slitrht motiiticalion-. each 
better and better, for so triliiiiL'- an ohiect as driviru' 
away tiies ; yet we should i>ause before bein:r too posi- 
tive even in this case, for we know that the d.-tribu- 
tion and exieteuce of cattlo aiid other aiiimaltt in South 




ANSI and ISO Tf 1' CHART No 2 




^'l Ml 2.8 


iH IP' 2.2 

t 1^ 




t. ^ 





'er. New York 1*6 
-82 - 0300 ■ Pfnr,. 
.88 - b984 • :. 


ON I UK t)KI(;i\ OF bI'K(lKS 

America ali-uliiU'ly d"|'':i(l< on tlu'ir jhh.t nf r<'>i.'<tini; 
tli«; Httarks of in-^fct.". : -.o tl,;it itiili\ uiti.iU wliich coiilil 
by any nif.-in-; (IcUTKi tliftn^t-h (■> froiri tliese mimU 
piicinit>, w.iuid l>e alilf t(i raiiu'c iiitn iit.'w pastiinw and 
liiii>< iraiii .'i ^Trat at!'. .intairt.". Jt i- not tijal \\ni lar^T'T 
qua-lnijiols arc artiii'.ly iii'>trny('(i (cm cjit in »iiin«' rare 
ca-rs) !.v fli»'s, liut t'lcy arf inct-^-aiitly li.ira->st'(l and 
lln'ir h-tr(Mi;.'th rrdu'cil. ~n tlial thev are u\<>vt' >ijl>;»'( t 
It) iii-»<', i)r not so \M'li rnaiilcd in a iiuniiiij <ii'ai-ili 
t.(» ■^•'arcli tor fixid, (ir to c^fajic troin l)fa-t- of Jiri'v. 

( )r^'an-; niw of" triiiin^r inijiortaMrt* lia'.c [iroliaMy in 
KOinc ra>o- 1»»^(MI ot li'irli iiM|»<irLaiir(' to an »'ar!v |>ro- 
j.'t'nitor, aTid, after iiavin;; (ummi .slowly jM-rto tfd at a 
foriiMT pcriud, lia\« lic»'n tran-rnittcd in iicarlv tiie 
k;hiio Ntatc. alllimijfli now iM'conm id vcrv >lii.'lit use; 
and afiy act "ally innirioii-i deviations in their ^<tnlcture 
will always have been chctlvcd hy natural sele.-tiori. 
Si-,'in:j; liow iinjiortiint an oiiraii of locoino'ion the tail 
i^ in nio>t aquatic animals, if.-; treneral prc-cnce and 
ii'^k' tor many j»ur|K)>es in so many land aiuniaK, whirh 
in tht'ir iunii^ or ri»odituHl swnnlil.-.ddcrs hetrav their 
li'jnatir oriirin, may perhaps he tiiiis accoiiiited tor. 
A Acll-(le\ehiped tail ha\ in;r heen tunned in an a'juatic 
animal, it nii::lit suli^i'tjiu-ntlv coiiu' to lie worked in for 
all ^o^ts of piirpcj^c. a.s a li\ -llajper, an oru^■ln ot pre- 
hen-irui, or as an aid in tiirni;i:j-. as witli the do;:, 
thoiiiili the aid mii-t. he sliirlit. tor the hare, witii 
har-.tlv any t.iil, can douhle (jiiickly enoii::h. 

Ill the «-<'i-ond [dare, we may sometni.c-: attribute 
importance to characters wlii( h are reali\ of very liltle 
impi»rtance, and "liiih ha\e or'^rinated from <ju;te 
sei onilary can^e-.. ind» pen ientiy of natural si-lcction. 
W'e should rememiier ttiat climate, food, etc., prolia'dy 
li.i' e >ome little direct inlluence on the or^ranisation ; 
ttiat characters reappear Irom the la\s' o(' reversion ; 
that correlation of ^jfpowtli will have had a mo>t im- 
portant inthience in modii'yinir various structure-" ; and 
luially, that sexual selection will otu-n iiave larirels 
moditicd the e\ternal character^ (d' animaU havni;: a 
will, to .'ive one mile an aihantaj^e in ti;.'titin{; wiib 



another or in ch.irmiiiir tin; females. Mnrenvor whoii 
;i modification of structure lia.H |irimanly ari-t-ri from 
the aixive or other uiikiiown causes, it mav at tir»t 
have h«'<Mi of no advatit-iire to tlie Hjtetie!*, but may 
Muli>t'«|iifiitiy liave i^'esi taken advantaije of liv tlie lio- 
sceiidaiits of the spi-cie- under ruw conditions of life 
and with newly acjiiired haliits. 

I'o ifive a few in.-tance- to illustrate tlM'>e latter 
remark-. If txn'vn wcmI jM-cker^ aiuiic hai! e.\iste<i, 
and we did not kiMiw thai tl/cre M»>re riiaiiv hlai k and 
pied kinds, I dare say that v\»« should ha\o thought 
tli.'it the jfrj-t-n colour nas a heautifu! a(].ii)tation to 
iiide tiiis trt'e-fre^jiietitiiitr hini from ibj enemies ; and 
conse.|UetilIy that it vv;i.s a cliaracter of imporUm.e and 
mitrht have heen ar(juire(l throiit:h natural -election ; 
HH it is, 1 have no douht tfiat the colour i.s du^ to some 
ijuite di-tinc-t cause, pndiaMy to -exual selection. A 
irailiiiff h.imboo in tiie .Malay Arciiipelaj-o climl.- the 
h'ltifst trees I>y the aid of ex<jui-ife!y constructed 
ho(.ks clii-tered around the ends of the iiramhe-, and 
this contrivance, no douht, is of the hiirhe-t service to 
the }»!ant ; hut as we see nearly similar liouks on many 
triM's v»lrich are not climbers, the hooks on the Lainh.m 
ni.iy have arisen from unknown laws of growth, ami 
ha\e l)een subsequently taken advantat'e ot by the 
piaiit undertroin;,' furtlier modification and l»e<-oniinu a 
ciimher. Ihe naked skin on the head of a vulture i- 
treri. rally looked at as a riirect adapLjition tor waMowiri;: 
in putridity ; aiul so it may be, or it m.iv jio-^ihlv lie 
due t(» tlie direct action of putrid matter ; but we 
should lie \ery cautious in drawimr any such inference, 
when we see that the skin on the head ot the clean- 
feediiii: male turkey is likewise naked. 'Hie suturt^s 
in the skulls of youn^r mannnals have been advanced 
as a beautiful adaptati<in for aiilinj: parturition, and 
no doul)t they facilitate, or may be indisjien-alde 
tor this act ; hut as sutures oerur in the «kul!s of 
youuL' bir(is and reptiles, whieh liave only l> eseaj>e 
iVom a broken vni:, we may infer that this structure 
has arisen from the laws of j^rowth, and h;i.s U'eri 







f' } 

tiken advaiit.uro of in tlio parturition of the hi:jher 


\\ o are profoiirnlly i:rtntraiit of tlio raii-j's pmdiicinjf 
s'liL'iit anil uiiiiniinrtant vnriatiori^ ; ami «♦» arc immedi- 
ately made rnn-cious of tliis l»y rtiicitiiiiJr on tlie <litfer- 
enres in tlio bree<ls of our domesticated animalh in 
<liftei-eiit (-onntries, - nmre e>jiecialiv in tlio 1^% i!- 
i-ed rountries wliere tlii-re iia^ Iieen Itut little artificial 
Nfdecfion. ( ar.'fiil oh<er\ers are convinced that a 
d iFTip dimato allcct- the L^ro«th of the hair, and tliat 
^^ith the hair tfie JioriH are correlated. Mountain 
l.rf('(N always differ from lowlaml hreciH ; and .i 
Touiintainous country would pro>>alily aliect the hind 
liiiiii^ from exerci'iinu'' tliem more, and orw-ihly even 
the form of tiie peK is ; and tlion hy tlie la* of homo- 
loiroiis variation, Iho frnut limhs and even the liead 
would prol.ahly he atfected. 'I'he shaj>e, al-o, of the 
pelvis mi;rht affect hy pressure the sli.ipe of the head 
of the yoimir in tlie womh. 'Hie lal)orioijs l)reathintf 
iiece<-ary in liiirli re^'^ions would, we liavo some reason 
to helieve, increase llie si/e of the chest ; and a«-aiii 
correlation would conio into play. Animals kept hy 
"-.ivaij-es in different countries of\en have to strugj^le 
tor tjicir own suhsistencp, and would t>e exposed to a 
cfrtaiu extent to natural selection, and individuals 
witli sli^rlitly diifcrent constitutions would sticcee«i hest 
under di;!erent climates; and there is reason to l>elieve 
that idiislittition aiul colour are correlated. A trood 
observer, al-o, states that in cattle susceptihility to the 
attacks of flies is correlated with colour, a^; is the 
liahility to he pois<»iied hy certain plants ; so that 
ciloiir would l>e thus ^uhieeied to the action of natural 
se'iM tiou. Hut we .-ire fir too ii^norant to speculati" 
O!! the relative importance of the several known and 
unkiiowu laws of wuiation ; and I have here alludt-d 
to thern only to siiow tliat. if we are unahle to acc(»unt 
tor the characteristic differences of our domestic 
tireels, whieh nevertheless wo irenerally admit to 
ha\e irisfn t!irou_r), ordinary ireuf ration, we oujjht 
not to lay too iiiiicL stri<-is on our limnran. e of the 




rnu>iO of the hli^lit ai 

iai():r<ni>. (lirit-re.'K 


tHfcn i^pecios. I miirht have addiu-od for tl 

•es I 

p'ir|)(w« the differt>ii( 
. hifli 

"k«Ml ; I 


ns g<'inii- 
race* of mm. are so stroii:;ly niarkf.l ; I may add that some 
li'tle lii:lit can a|i[iaroiitly ho thrown on tlie orii,'iii of 
thf-ip diffprerice-i, chipi'ly t'hrouifh sfxual >;fle.-tion of a 
|i.irtirular kind, hut witii«»ut here t'literin:; on copious 
d»'Mils my reasoning would appear frivolou'*. 

J he foreifoinj? rpinarks lead me to «iv a few word>i 
on the protest lately made hy Hom« naturali-^t^, airaiiist 
the lit: itarian diMtrine that" everv detail of structure 
has heen j>rodii(ed for tlie pood ol its possessor. Ihev 
Kelieve that very many structures have heen created 
fur heauty in tlio eyes of man, or for mere variety. 
liiH doctrine, if true, would he ahsoluteiv fatal to riiv 
theory. Vet I fully admit thai many structures are ot 
no direct use to their possessors. Physical conditions 
|,n.hahly have had some little effect on structure. (,uite 
M.dept'ndently of any irood thus pained. ( orrelation 
or i^Tuwih has fio douht played a most importiint part, 
and a useful mo<lifi.ation of one part will otten have 
entailed on other parts diversified chanfjes of no direct 
iiM'. ;?o a<ain character.-, whicli formerly werfl u.seiul, 
or ^vhich formerly had arisen from correi.ition of 
irvi)\\\}\, or t om other unknown cause, may reappear 
from the law of reversion, thoueh now of no direii 
u--. I'he etfects of sexual selection, when displayed 
in heauty to charm the females, can be called useful 
only in rather a forced sense. Itut hy far the most 
i'nportant consi<ieration is that the chief part of the 
oivanis.ition of e\ery heintj is simply due to inherit- 
•T.-e ; and conseijuently, thoutrh each heinjr assuredly 
!« ^vf'il fitted for its tda.-- in nature, many structures 
ni.w ii.ive no direct rela:!..:i to the hahits of' life of each 
s|.ec;es. Thus, we can hardly helieve tliat the wef.hed 
'•'•"t of the upland tr„„se or'of the frijrate-hinl are of 

' ' '"^ ■-"•' ■-"^■"' :;;rr;:i , rarinni: rn-iie»e llial tfie 

sun.- hones i:i the arm of the monkev, in the for<>-le*f 
ot the horse, in the wintr of the hat, and in the flipper 
of the seal, are of special use to tlie-e animal.s We 





may pafcly .ittriliule tlKvo >triji'tiirps t^) inlif riUnrfi. 
Hut U> llii- pr(i;:fiiit()r of tlio upland ifoost) ami of tlie 
friir.'itp-l>iril, \vt'l»l»o«i fp«'t no doiiht wppf a^ UHefiil afl 
tfioy now ari> to tlie iiiif^t aipiatic ot pxiHliriu l.inis. 
>o we may U'lit've that the [)ri»:.M'nltor of tlie >'»-al had 
not a flippor, hut a font nifh five toes titt«'d for wnlkini? 
or ^rra.«|>intr ; and wo may furtlwr ^entiiro to h«'l fve 
that tlie -cveral hone^ in the linrtw nf tln» rnonkfv, 
horse, and hat, which liave hi-cn inhcnred from a 
'•omni(»n iiroy'eiiitor, were formerly of iiinre sjn'cial line 
to that iiroi:«Miitor, or its |iroirenitorH, than tliev now 
are to tlie-o aiiimals liavinjr '■uch widelv di\ (>r>.iri»'<i 
liahits. riieretore we may infer that tln'-t» several 
liotie' mi^rht have heen aecjuircd throii^'h natural «elee- 
.ion, ^uhiccted formerly, a.-, iKtw, to thf sever:il laws 
of inheritance, reversion, correlation of trrowth. etc. 
'■ ience ever\ detail of structure in every livinc creature 
, making- ^o:Ile little allowance for the direct action of 
|ili\sical cf)nditionv; »»iay lie viewed, either as havint; 
! een of special u>e to some ancestral form, or as beintr 
now of siiccial u«e to the descendants of this form - 
either directly, or indirectly throuuh the comide.v lawn 
'1 jfrowlh. 

Natural selection cannot possihly produce any modi- 
fication in any one sjiecies exclusively for the irood of 
another sitpeios; tliitii^h tlirou^liout nature one species 
incessantly takes advanbuxe of, and jirotiLs by, the 
structure of another. Hut natural selection ran and 
doe-s often produce structures for the direct inpiry of 
other -.pecies. as we see in tlie fans: of the adder, and 
in the ovipositor t\f the ichneumon, by wliich its eye^ 
are deposited in the li\inj.r bodies of otlier insects. If 
it ♦•ould be pntved that any j»art of the structure of any 
one species had been forned for the exclusive g-oid of 
anotlier sjKH-ies, it wouhl annihilate my theory, for 
Buch ciiuld not have been produced throutrh natural 
xelection. Althouirh many statements may be found 
ui works on natural history to tins effect, I canm»t find 
even one which seems to me of any weitrrit. It is 
admitttnl that the rattlesnake ha" a ^M)ison-fanir for ite 



own defeni-e ami fur the dpstructinn of its prov ; hut 
iH»ni#> .lutliorn hiippose that At the same time thi^ Miake 
in f urni-ht'il with a rattle for it» own iiijiirv, namely, 
to warn its prey to e»»-ane. 1 would almost as noon 
holieve tliat the cat curU the end of it.« tail wlien 
pr«'parin>f to spriiisf, in order to warn the doomed 
mouse. IJut 1 have uot space here to enter on thia 
and other Huch c.ises. 

Natural seltMtioii will ne\er proiluco in a tieiiii? 
anything iiijurious to itself, for natural ^election actn 
Mdely hy and for the trood of each. No oriran will Ite 
formed, as I'aley has remarke*!, for the purjtose of 
cau>iii'.' jKiin or for diiinjf an injury to its po>>e,ss<ir. 
if a fair halaiice l>e Ktruck hetv\«'en the trood and 
evil caused hy each part, each will he found on the 
whole advantageous. After the lap-e of time, under 
chani:in>f conditions of lif", if any part comes to ho 
injurious, it will be modified ; or if it be not so, the 
bein^' will hec-ome extinct, as myriads have l)ecom« 

Natural selection tentls «)nly to make each ortranir 
heifitr as |>erfe<-t a.«, or slightly more perfect than, the 
other inhabitants of the same country with which it 
ha* to strutrtfie for existence. .\nd we see that this ia 
the dejfree of {)erffcction attained under nature. The 
«Midemic produi;tioris of New X 'anil, for mstam e, are 
(•crfect one compared with another ; hut they are fiow 
r.ipiiily yieldintr before the advaficin<f legions of planUi 
aiid anifnal.s i.'itroduce*! from Kurope. .Natural -flec- 
tion will not produce absolute perfection, nor do we 
.ilways uieet, a.s far as we can judtre, with this fiitrh 
suiwlard under nature. The correction for the ai>erra- 
li<in of lio^ht is said, on hi<^h authority, not to be 
{.erfect even in that most [)erfect ortran, the eye. If 
our reason leads us to admire with eiilhuviasm a multi- 
tude of inimitable contrivances in nature, this same 
rea**on tells us, thoutrh we mav easily err on both 
sideu, tiiat some otticr contrivances are le^s perfect, 
(an we consider the *tiiii: of the wasp or of the bee 
a- i>erfect, which, when u-ed atainst manr altackiiifi; 



iuiiiial.s, carihot be witlnlrawn, u^luis to the backward 
Hcrratiires, and ho itieviUihly rauseu the death of thp 
iriKert by trariiij; out its vis«'ora r 

If we look at the stint: of tjie Ik-*-, a** haviiiff origin- 
ally existeil in a remote progenitor as a horinjf and 
serrated iriMniinent, like that in so many nu'mJ»crs of 
the name jfreat order, and whirli has he. :i niodifuMj hut 
not perfert,.,! f,,r \\< pr.'-ent j.^rpoM'. with the j.oison 
ori;rinalIy adapted to cause ffalls Kiih>e(jiieutly intensi- 
fied, we ran jierlians understand how it is that the iik<« 
of the stintr should so oltfi cause tiie insect's own 
death : f(.r if on the wliole tiif power of Htin^'in^' U' 
useful to the commiitiity, it will fultil all the re-juire- 
nients of natural selection, thouirli it may <ause the 
death ot m.rno few niemlwrs. If we admire ttie truJy 
wonderful power of scent by wlijch the males of many 
in>e. Ls find their females, vau we admire the pr<»duc- 
tiori for this sintrle purpose ot thousands of drone>, 
'vhich are utterly useless to the community for any 
• ■th.-r end, and which arc ultimately slau^riitere*! In 
their industrious and sterile sisters?" It may be ditii- 
ult, but we ou<rht to admire the savage instinctive 
iiatred of the quetn-bee, which urpes her instantly to 
■lestroy the yountr queens her dauuhtcrs as soon' an 
l»orn, or to perish lierself in the combat ; for undoui.t- 
<<ily this is for the pood of the community ; and 
maternal love or maternal hatred, tliou^h the latter 
turtunately is most rare, is all the same to the inexor- 
able principle of natural selection. If we admir.' the 
several in/mious ctuitrivances, by which the tiowers of 
the orchis and of many other ' jdanti* are fertilixnl 
ihrnutrh insert a^'ency. can we consider as equally 
perfect the el.iboration by our rir-trees of dense cloud's 
nf pollen, in order tliat a few trranuies may be wafted 
■y a < hance breeze on to tiie ovules.- 

<u>i.,u.iryo/'%:i.f.>r.~\Vv have in this chapter di*- 

>>e Lr-ed a-aiiist my theory. Many of them are very 
-erious ; bat I tliink that in the di>cuUion lijrlit Las Ihu n 



tlirn'.vn oil several f;i(tw, whirli om tlie theory <>f indp- 
ii»MiiitMit arU <•! «ri'atinri are uttorlv oWsciire. ^V e li.tve 
'•ecu that sjK'cipt* af any otie {xTicHi are ii<it iinlctiiiitoly 
' arial'h', ami are not liiike<l totrt'ther by a iniiliiluile 
of iutornuwii itf irrai!ati(iii>. j>arily Id'iau^f tlio nn ««'.«•> of 
natural >«'lri ti(>ii will always In* \fry >-low, and «ili .Kt, 
at any (nu* time, only on a vfry tew (nrni!* ; and jiartlv 
>>o< aurte the very |»riMcs- ot natural M-Uvtinn 
implies the continual sujtplantini.'- and extimtioii of j>re- 
re<linir and internu'diate gradations. < lo><'ly allied 
«|K.M-ies, now living on a continuous area, mu^t otten 
have heeii formed \*hen tlie ar»>a v»a^ not continiiou**, and 
viien the itinditioii> of life diil not in^enNihly ^Taduate 
may from one part to another. \Vhtii Iwo varieties 
■.re fornuMl in two districts of a enntinuous area, an in- 
•» rnieiliate \ariety will often he forme«l, fitted for an 
intermediate zone; hut from reasons as^itrned, the inter- 
mediate variet} will usually exist in'r numhers tlian 
the two forms which it coniieets ; «:onse<|nenlly the two 
latter, during the course of further modifcation, frorii 
f*xistintf in greater numhers, will have a trreat advanfaice 
over rhe less numerous intermediate variety, and will llius 
ireuerally sueceed in supplanting and exterminatin:; it. 

\\ e have seen in tliiv chapter how cautious we shouhl 
t>e in <-oiu ludiniT that the most ditlereiit,s of life 
lould not graduate into each otht-r ; that a hat, for 
iu-tan<e, could not have heeii Inimeii \>\ natural r-«-lt'<'- 
tion from an animal whicii at fir>t could only taiie 
ihroueh the air. 

\\ e liave seen that a >j>ecies may under new t«uidi- 
tiou.s tit lite ( haiiire Us h;ihit>, or have diver^itie^l hahits, 
Aith some liahiLs very unlike tho«.f of it- nearest con- 
treners. Hence we can understand, hearing in mind 
that each orf^anic Iteinc is tryin^,'^ to live wherever it 
ran live, how :t has ari-eii that ti ere are uplami uee>e 
Mth wfhhed feet, ground vvooilpeckers, diving thrushes, 
ui.i petreU with the hahits of auks. 

.•\iuiougii the ix'iief that an or^raii so perfect as the 
eve could liave heen tcjrmed l)y natural ^electiou. ia 
more than ent)ugh to stagger any one ; yet in the case 






of any orcan. if we kinnv of a l„ti^ s.-ripM cf t'nulationi 
m .-..rTii.leNitv, ear), ^'ood for ify po^M'-or, then ijri.i.'r 
rli;iM:.'mt' .•..ii.iif ioii. of lif,. tl.rr.. is „<, lotr,,.;.! j,„,,o^^i- 
I'ility III tlio arriiiir.'r.u'iit of ,injr n..„».ival,|t. <i«.;.-Trf of 
ptTNTtion throuu'li natural srlc, tion. In tJie ras^« in 
wliicli H.. kn..vv«,f no int^rmp.liat.' or traii<ifi<»;ia| nXMet 
«« slioiild No very <-a.ifioii« in con. huiins: that 
< on I.I liavo oxiste.!. for the Jiomoloir:.s of rnanv or,fan.H 
an. I tli.'ir nit.-rTni'.iJati. states -liow tliat WDndfrfiil meU- 
MiorplioM- in tun.ti.»n are at loast |,o<>il,lp. } „r iintanre, 
a s>*Mn-!ila.i.i«'r has apparpfitiy Wen convrrt»'<i into an luinr \uuu. I In- varne oriran havnii: i.erf..rme»l 
Kimultan»..,ii.lvMery.litr«.n'ntfijn.ti..rH,an.i th.-n haviriff 
l).'««n s,„.rialiM'.i for one function ; and tw.. very dis»iru-t 
orjrans havinji perfornie.i at the Mani« time the s;inie 
funrtion, flu- one having' heen i)erfe<ted wliiUt aide.! 
hy the other, must often have largely fa.ilitited 

\\ e are far too i;rnorant, in almost every case, to be 
enabled t.) a^-ert that anv part or or^'an 'is so unim- 
portar.t (<■ the welfare of a spe.ies, that modifications 
in Its Htru.tnre could r..,t have heen slowly accumulated 
hy means ..f natural sele.tion. IJut we may cnti-jently 
heheve that many nio.iifications, wh..llv due to the laws 
ot irr.)Mth, and at llr^t in no wav a<ivantai:eous to a 
sj.e.ies have heen taken advantage of hv 
tlie still fiirth.T modified descendants of this s{K.cies. W'e 
may, aUo, believe that a part formerly of hiirh import- 
ance has often been retained (as the tail of an a.|ualic 
animal hy its terre-trial descen.iant.s}, thouirh it has 
be.-ome of nich small importance that it .•oul.l not, in 
Its present state, have been a.-<i.iire.| by natu-al selec- 
tion,- a i.ower which a.ts s.dely by tlu' preservation of 
prctitable variation- in tlie strutrp-le r,.r life. 

Natural selection will produce nothiiiir in one s|>eciet< 
f.)r the e.xdusive p..od or injury of another; though it 
may well produce parts, ..r^'an's, and excretions hrtrhly 
iisi!;;i or i\fii ii,ii|s,„.„sai)ie, or hi::iiiy injurious to 
another species, but in all at the same time u.^ef>Jl 
to tlie r.v*,„.r Natural selection in each w, 11-stucked 




roiiiitry, tuuMt act chiotly throiii^fi tho fomix'tjtiiti of 
Oif iiilialiirant^ one h itii aiidtlicr, and fniiscqiioiitly will 

[irtMlijie jKTffi'iioii, or strTijrth tii the l»attle lor life.milT 
.i« . nnliiijf to tlif Htamiard uf rountry. Heme tl.»' 
irili.ii>itaritj* of one roijiitry, ^reneraily the »itiiaiUT one. 
Will titXvn yielil, h8 wp M'e tlit'V do yield, to the iiiha- 
liitaiitx of'aiintlipraiid c«'iii'r.ill\ l.irifer rountry. For in 
the laruMT couiitry there will have oxi>.ted more indi- 
viduals, ami more diversified fornin, and the fom|>etition 
will have Keen severer, and thus thestandanl of iM-rfec- 
tion Hill have l)een rendered hitrher. Natural selettion 
\*ill not necessiirily pro<lure ahsolute |>ert"e«tion ; nor, an 
fir as wp tan judjje hy our limitetl fiu'ulties, can al)S<ilute 
perftH'tioti ]i« everywhere found. 

On the theorv of natural selection we ran i u-arly 
iindersUnd the fiill meariini; of that ol<l <-anori in natural 
history, 'Natura non facit salturn." I'lii-i i-anon, it 
we look only to the present inhahitafits of the wtirld, in 
not strirtly correct, hut if we include all those of j« 
tinieH, it must hy my the«>rv \te strictly true. 

It is generally ackiiowledued tliat all uriranir heings 
• ave heen formed on tw<> treat law.s- -I inty of Type, 
Hiid tlie ( onditions of Kxistence. By unity of tyi)e is 
rT.eant that fundamenUil aurpemetit ifi structure, which 
we see in ortrainc hemirs of tlie siiine da.-^, and which is 
(^uite ir)de|ietjdent of their hahit« of life. On my tlieory, 
unity of type is explained hy unify of descent. The 
exjire^sion of conditions of existeru e. «o often insisted on 
hy the illu»trii)us ( uvier, is fully eftil. raced hy tlie prin- 
ciple of natural s«'!ection. For natural selection a( Ls by 
either now adaptinj; the varyini; part.* of eiuh iicin^f to 
it*i ctrtranic an<l inortfanic conditions of lite ; or hy having 
adapted them durintf l<)nt-{>a>t jH-riods of time . the 
adaptations heiiiji' aided in >(>rne ta-se.s hy use and dis- 
u>.e, hein;; sliirhtly affected hy the direct action of the 
external conditions of life, and heinij ifi all cases suli- 
lected to the several laws of trrowth. Hence, in fa«t, 
tlie law of the Conditioas of Kxi>tence is the hiifher 
law; a>i it includes, thrim^'h the inherr.ance of former 
a<i.iptation<, that of f'nitv of Type. 


en A 1' IKK VII 

I s - 1 1 .s n 

i;i»tlni-U c<in,i.»rMl.le »iUi I »lnu, uut in tlirir ....jtin- 
jintii-tfl j:r«.|ii.»ti-.J A|.lii.l.-.< >ii>l MiU Init.ii. In— 
!>• Mi.»ti.' iiiitiii. tt. their^'iti .N«tiir«l iiigtlmti ..( tl.r . u.k.". 
uttiil.. arhl puia^idc t»i-i, -M»ve iii,ikii.>;nitB Huv Iff lt» 
i^<l. I'iakiiiK liutiM t-imii. ultic* on tl,. thi-.rv ..f tlir 
hchiii.iij i.f in, mil u .NfuU-r or it< uk- iij»ccu' Saimoary. 

Tbk Mjlfject of iii>tiut:t nii;,'lit hav«.- \>f^^n worked into the 
I r.\ inns cli.ij.lers ; hut I liave thoiitrlit Dial jt wduld Iw 
mori. c(mv»;iiitMit to treat the suhjctt te|«irately, «'sih«- 
cially as ro Moiiil»>rfiil an iii.xtiiict aa that of thr Iiivc- 
i»eo makiiii: its rolls will proliahly have n.cjrn-d to 
niaiiv rc.Kirrs, UH a <litii«ulty siitricioiit to o\t«rlliroH- my 

**''''"'^' *' ry- I must preniist., that I hav». nothiiifr to 

do wiih Ihp oriiriii of the priniarv iiiontAl pow.Ts. any 
rnon- lliaii 1 ha\.' willi that ot lifw itself. \\ v arc con'- 
cerned txily with the diversitii's of instinct and of the 
other mental qualities of ariimals \H;thin th<> sam»> 

1 will not attempt an\ ijefuiition of iuvtinrt. It w.-uld 
!mj tM>y to show that several distinct mentiil actions are 
commonly emhraced l.y this term ; hut every one utuler- 
st-nd.^ wliat is meant, wlu-n if i^ <ai(l that instinct imj.eU 
IheiucKooto migrate and to lay lier ejfcs. in other hinds' 
nests. An action, which we ourselves >liouM re.juiro 
experience to enahle us to [lerform, when performed hv 
r.i: .-.;;.:::.;;. ri.wrc t.-j.o, -.iii\ t»v a \ t;ry vounjr One, witiiout 
any expei-i, n(e, and when |^«rformed hy many indivj- 
di;als Ml tl,c s.-.:,ie w..v. wiiliout their kn<)\\:n4r "t«.r miat 





P'irpOM- It i» pprfornuHl, is UMially muI to b'.« iimtiiirUvp. 
Fiut I could kImiv* that iinrip of tlicno rhanirtrrs .if 
iiiHtinrt ar** iiiii\«'rsal. A little do-*, »<* Tiprre Hiib^-r 
••inre.-isr-s it, of iinitrmpnt or reii-mi, often mmes JMto 
(.lay, »'\oii ill ariiinalH v.-ry low in the srale of nature. 

lie<lerirk ( uvier and wneral of the older metaphy- 
sicians have « onijMred instinct with liaMt. 'I his cuiii- 
parison pivea, 1 think, a reinarkilily arcurate notion of 
ihr frame of niifi I under whuh an instinctive action is 
[►ert.irnied, hut not of it« origin. How nnroiisrioiisly 
many hahituai actions are performed, indeed not rarelv 
in direct o|>|>o«.ition to our conscious will ! yet thev niav 
l>e nioditied hy the v*ill or reason. Hahits e'a.sily iM'come 
a«f.ociate<l with other hahits, and with cortAin |H«riod* of 
'.mc and sUl«»<of the iM.dy. When once ar()uired, they 
often remain consUtnt throutrhout lif»- Seven! other 
points of rese'nhlance between in.stinct-s and hahits could 
>e pointed iiut. As in repeating a neli-known none, so 
in nistinctfl, one action follows anoilier by a sort of 
rliythm ; if n |>erson Iks interrupted in a Hon|r, or m 
rept-atinjf auythin;,' hy rote, he is jrenerally forced 'o 
go iiack to recover the hahituai train of tlioujflit : st» 
1'. Hubor found it was with a caterpillar, which makes a 
• ery complicated hammock ; tor i( he took a caterpillar 
i^liich had «-oniplete<l iU hammi>ck up to, Kay, the sixid 
-Liiife of construction, and put it into a hammock com- 
plet«^ up only to the thinl statfe, tlie caterpillar simply 
re-performed the fourth, fifth, and sixth staires of con- 
-'ruction. If, however, a caterpillar were tiken out of 
■I hammock made up, for ii.>tance. to the third sLnce. 
;.rid were put into one finished u[> to the sixth ^1:0:0, ^n 
that miK li of its work was already done for it, f'r from 
fei'iiin: tiie iM-iietitof this, it was much enil)arras.sed, and. 
in order to complete its uammock, ^e«•med fon ed to 
sUrl from the third sUjfe, where it had left off and thiif 
tried to complete the already nnishe<l work. 

If we sujtpose anv habitual act win to become in- 
hrrite.i -and I tlnnk it can Iw •.I,ow,i thai this dop* 
sometimes hap|>eri then the re-.rnblance between uhat 
oripi'ially a habit and an instinct U'.onu-s so close 



;i> liiit to \tei diKtinjfuished. if Mozart, iri>t(>ad of i)layint? 
tli(> fiaiiofort*' at thrre years old with w<)n<ler»uily littlr 
pracrii-p, hail played a tune with no practice at all, lu« 
niiL''!:! truly he said to have done ^o in-tinctuelv. Hut 
it «,iiiid he the rno«t 'ieriuuM error to sup[io-e that the 
gTiMtcr iuinil»»'r of iijst;iict.-< have heen acijuired hv habit 
ill on<« ueiieration, and then transmitted t»y mnentance 
to Huci e<>dinc- ?eneration>'. It can he clearly >howii that 
the rimst •.vniidertul in.->titict>- witli which we are ac- 
•ILiainted, namely, tho^e of the lii\e-hee and of many 
^uis, could not [inssihly liave heen tlius aci)i;iied. 

It will he univvsaily admitted that in>:;iict,s are an 
important as cj)r[)oreal structure for the welfare of each 
•jpccies, under its present conditions of lih-. Inder 
chan^-ed condit:oni of life, it is at least p<i>*jlde that 
sii::ht riioditications of instinct miulit he proiitahle to a 
spciies ; and if it can he shcmn that instincts* do var\ 
t\e- so little, tfien I can see no diJFn ultv in natural 
selection preserviinr and continually accumulatiiiff 
variatiicis of instinct to any extent that may be 
profitable. It Ih thus, as I believe, that all the most 
complex and wonderful instincts have ori:rinateii. As 
moditications of corjKneal structure ari-e from, and are 
increased by, use or habit, and are iliminished or lost 
Uy disuse, so I do not doubt it has been with instincbj. 
Hut I believe that the effects of habit are of ijuite 
suiiordinate importance to the effects of the natural 
ielection of what may be called accidental variations of 
in-iiiicts ;-~ tiiat is of variations produced by the same 
unknown causes which produce .4if;ht deviations of 
i»i)dily structure. 

No complex instinct can pos>ibly he iirodm cd tbrough 
nitural selection, except liy tlie sl^w and »rradual 
accumulation of numerous, sliirbt. vet j>rofitable, 
variations. Hence, an in the ca -e of corporeal 
Mtri.'itures. we ouiriit to find \u nature, lutt the actual 
transitional ^rraditimis by which each complex iiiPtiuct iifcu acquired for these couiij he tdund only ui 
the lineal ancestors of ©;ich specievS — but we oujrht to 
find 111 tfi« collateral linen nf deaceiit some evidence of 




mich jrraiiztions ; or we oui^ht at least to be alile to 
«;how that graHatioiiH of some kinil are possiblt* ; and 
tluH we rcrtaiiilv laii <lo. 1 have })oon surpri><«'<l to 
tiiid, makiiiir allow.iure for the iii<tiiiftH of animal- 
having' Im'om Imt little ohservwl except in KiirojM> atid 
Nortii AriH'ri''a, and for no instinct hi'inL' kno«ii 
amo; iTst I'xtiiict sy»eci(>«, liow very trpni'ral!y uTadatimw, 
Icadiri ■' to the most comjilex institMts, can \»' discoveri'd. 
('liain^'s of instinct may sometimes Im* facilitated l>v th. 
same species haviiiir ilitfereiit instincts at dirierepji 
perind^ of lire, or at different seasons of the year, >>' 
wlien placed under different circumstatices, etc. ; in 
which cise either one or the other iiiRtinct mii.'ht he 
pre>»'rve ' hy natural Belectiori. And such instances of 
liiverMty of instinct in the same species can he tihown 
to occur in nature. 

Atrain ris in the case of corporeal -tnicture, and ron- 
fortiiaS: vith my theory, tlie instinct of each 'species ;•. 
e<><vi for itnelf, hut has never, as far as we can judir--, 
heen jiroduced for the exclusive {rood of others. ( >ne 
or the strontrest nistances of an animal apparentlr 
performintr an action for the sole (food of another, with 
whii )i I ,im acquainted, is that of apliides voluiitariiv 
yield iti:r their sweet excretion to ai-tH : that tliey do so 
voluntarily, the followintr facts show. 1 removed all 
the ants from a (jroup of ahout a d(»zen aphides on a 
dock-ji!.int, and prevented their att<Midance duririir 
several liours. After this interval, I felt sure that the 
ajdrdes would want to excrete. I watched them for 
some time through a lens, liut not one excreted ; I then 
tickled and stroked them with a hair in the same 
maimer, as well as I could, as the ants do with tlieir 
anteinia* ; hut not one excreted. Afterwards I allowtni 
an ant to visit them, and it immediately seemed. i>v its 
eajj'er way of rumiin^f ahout, to 1m» well aware what a 
rich flock it had discovered ; it then iM-tran to play with 
itj» Antent!»> riii tlie .iJidomeri first of one atihis arid then 
of another : and each aphi*. .as booh a.s it felt the 
anteniue, immediately lifted up iUs alnlomen and 
excreted a limpid diop of iweet juice, which was ea^rly 



ilevoiired hy tin- .i)if. K. in the (|uitt> ymiii,' .iphido* 
iK'li.ived iu this m.iiiinT, >hr»\virief that the .utidn wa.^ 
iiistiiH-tivp, and not tlie rosult of oxperitMii-t*. H.jt a- 
tho <vx(-retiou is extremely viscid, it is proh.iMv ;• 
t'oMveiiicnce to tlie aiihi(lf>i t«» have it removt'd ; iinu 
therefore jtrohal'lf the aj)iii<le«< do not iiistitictively 
eA.rete for tlie sole eood of the ants. Althousjh I do 
not believe that any animal in the world perloriiH an 
ai tion for the exrlnsive tjood of another of a rii.stinct 
Rpeeies, yet earli si)eries tries to Uike advanta^^'e of the 
iii^tiiiets of oflier-:, as each tikes aiivant.wre of the 
waker l»odily structure uf others. So a^-ain. in some 
uw cascM, certain inslincb< cannot ho con-dered aa 
aitsohitely perfect, hut a.« details on this and otner such 
points are not indi-per:-:'.hl.', they iriay he here [ii.^sfd 

As some deirree of variation in instincts nruier a state 
of nature, and the iniieritmco of such variation-^, are 
ii,.iis|)ensahle for tiie action of natural selection, as 
iiiiny inst.inees as possible ouiflit to he here ^iven; 'out 
nant of space prevents me. I can only assert, that 
instincts certainly d(» vary — f(tr instmce, the miirratorv 
instinct, Inith in extent and directiitn. and in its total 
loss. i>o it is with tlio nests of birds, whicli vary partly 
in depe.nlence on the situations cho-cn, and On the 
nature and temperature of the country inhaliited, hut 
uften from causes wliolly unknown to us : Audubon has 
tfiven s.-Noral remarkalile cases of ditfereuces in tiie 
ne-t.s otthe same species in the northern atid southern 
I'nited States. I'car of any particular enemy is 
certainly an instinctive (luality, as rnav he seen in 
nestliiii,' liinis, thoiijfh it is strent,'tlieiied hy experience, 
and bv tlie sijr'it of fear of tiie s.iine enemy in «tther 
animals. But fear of man is slowlv acijuired, as 1 
l;ave elsewhere slutwn, by various animals inhaltitmg 
fesert islands ; and ^c may see an instance of this, 
eveti in Kuirland, in tlie trreater wildness of all our 
larye birds tlian of our small birds ; for the larire birds 
have b.-.'u nio-t per.-ecuted by man. We may safely 
ftttriluit- the ^rreater wildness of our larife birds to this 



.Mii-f ; for in uninh.iSiti'd islarnls larijp hinl^ aro not 
ii»(»r«> ft-arful than muiII ; and the m.i-j)ie, so w.irv ii, 
KiilM.ukI, is tame in Norway, as is the hooded crow in 

I hattlie ^T'THTal (ii«|»(.s!tlun of individuals of tl-.- ^,tm.' 
^;>>s,ii.)rri in a state of nature, is extromelT div.rsiti.'d, 
(Mil 1)0 sh.iwn hy a multitude of facts. Sevor.ii ci^cj 
aUo, could hefjiven, of ncra«ioiial and strarii^e liaMts in 
..Tt.iin species, which niiifht, if advanUircous to the 
-p-.if"!, ^ive rise, throuirh natunil selection, to quite 
ri'Nr instincts. l{ut I am well aware that tii.-^e ir'Mieral 
-t.ifement-, without fact,s j:i;cn in detail, <-an produce 
!.ut a t.M-i.Je effect on the reader's min.l. I can only my assurance, that I do not speak without ^ood 
t'\ idi'uce. 

Ihi' possiliility. or even pndtahihtv, or inherit«'d of instinct in a state of'iiature will ],v 
-trciiirtlu.tied hy hric/ly consideririir a few cases under We >t'iall tlius also l>e enahlcd to se*« 
the respective parts which hahit and the selection of so- 
called a.cidental variations have played in modifyin-; 
• fie mental (jualities of our domestic animals. .\ numlK'r 
of curious and authentic instances could he jriven of the 
in) eritaiice of all shades of disposition and tistes, and 
i Kewise ot the oddest tricks, as.sociated with certain 
frames of mind or periods of time. Hut let us look to 
thi familiar case of the several hreeds of do^'s : it 
cannot he douhted that yoiinir pointers (I have mvself 
seen a strikinif instance) will -ometimes point ami eveu 
hi( k other d«»tfs the very first time that they are taken 
"tit ; retrieving is certainly in some dejrree iiilieritcf! by 
-e'rievers ; and a tenden.'y to run rou!id, in-^tead ot at, 
a ilo. k of sheep, hy shepherd-do^s. I cannot see that 
th-M> actions, performed without e.\perien<e hy the 
vi>!jri:r, uid in nearly the same manner hy eacli' indi- 
vidual, performed with e;urer deli<fht hy eacji i.reed, .-.nd 
»vitl.(eif the end heinj? known, — for the vouni.' ■•'..'•'.'■•er 
can no more know that he points to aid his master, 
'han the .vhite huttertly knows why she lays her e^-if« 
on the leif of t)ie cahhatre,— i cannot se« that these 








.trtioii" differ ossentiallv from trti»> iiistinct.«. If we 
were to «pe oiie kind of wolf, wIumi yum.ur and without 
iiiv tniiiiiiitr, a.« -^'op n> it sr«Mit»>d its prny, st:iiid 
rr>(.ti(.rile-.v. T k.' a --tat'j.-, and then -lo-.*ly crawl forward 
H-itl, ,1 |,.Tuli;ir un.t ; and aiiotluT kind of wolt ru^liimr 
ro.iM.i. ni<tra.i oi at. a h.-rd of d.-.-r. and drivinc tli.-m 
U> a distant ].- ;it. wt- >lioiiId as-urcdly .all thoj'f a.'lion^^ 
in-^tiii.tivH. I>'.i.i.-.tic in^tln;•t.s as t'hoy may b*> .all.'d, 
arp (•♦•rtainlv 1 vr less fixed or iiivari;iliK- tlian natural 
in,tin(t,s ; luit tli'<v have l...'n act- ,1 uii t.v tar Ifss 
rii.'ornii- scl.Mtion.'and !iav.' h.-cn trinMoitt-d tor an 
incnmi'aral>!v shorter i.tTiod, uinler Irss fix.d rondmonH 

of lift'. ... 1 , ■, 1 

Hmw ■^•rMn_'-ly th<'>i»' di)mtwtic in>tinftx, tial)il-, an»i 
di-M.- t o 1- art' iiili«'rit"d, and liow rnrioiisly tli«*y 
\>rrnuM' w.'i! -'howii u lifn diir.-rtMil l.rtH-ds of 
dn;rN ar.' .To-.Mi. TliM-^ it is knovMi lliat a rro^s with 
a tpill-(l'(L' l!a---a*f.M-t.'d for rii.iiiy trcnt'rations th," roiira>r<-' 
and ol,-t~ia<-v of -rrc. iiOUTi li ;' and a cnws witli a crt-y- 
ho'ind has LMvi-n to a wliule family of >l,.>idiiTd-.ioir^ a 
t.Mid.-n.-y to liunt liari's. I'Iu-m' dom.'.<tic ui^tni.t^, 
«-ii.'n Ihiistest.'d l,v'Tii-.o,iiir,r('<.'mld.; natural mslinrls, 
\v!);.li in a like "ni iiuuT h.-ronu' curiously blended 
u> ^'thor, and lor a Ioiil' i..Tiod exhihit tracps of the 
iiiHtim-t-sofr 'lerpan-nt: for exami-U', Ia- Hoy drMTil-os 
;i .lo;,'. wlio-o irreat-irrandfalhor was a wolt, and this .lo^' 
sho^ri'd a tra.o of it.s wild j.;.rtMiti;rtM>nly in one wav, by 
iio^ .•omiiiiT in a -trai-ht line to bis master when callwl 
I 'ome,f ic instini'ts are sometiine> spoken of a> action-- 
which havo become inherited sohdv from lontJ-continue<l 
and c .mnulsorv habit, but this, I thiik, is not true. 
N'o (,„e would ever have thoutrht ot teaclnnir, or 
nrohahly could have tinit'ht, the tumbler-i.i>,'eon to 
tumble -an a.tion wln.ii. as I have witnessed, is per- 
formed by vounur birds, that havo never seen a ^)iireoii 
tumble. '\Vo may believe that some one pitreou siiowed 
a -li::!it tondencv to this stramre habit, aii<i that the 
lotitccontinued selection of tiie be>L indiv;du<ii:^ in 
pucces.ive trenerations made tumblers what they now 
are • and near (Jla-vow there aro house-tumblers, as I 



hoar from Mr. Brent, whirh i-aniiot (iy eitrhtccri incliea 
hiirli without t'oiiiu' li.-.i.! ovt-r ht-rU. I't may U- (luiil)tt'd 
wht'thiT any om- would liave thought nftr-iiniiiir a ilojr to 
point, liail not M)mf I'ne doy naturally -hmvn a'nfy 
in this lin»' ; and this in known orca^iunally to lianin'ri 
.1^ I once S.-IM in a j.uro terrier: tin- a. t oV |Miiiitinir js 
[irohahly, a> man) h.i'c thoutrht, o?ily th<- e.\au:rerate«l 
[Mii^e of an animal preparintr to >jirin;r on its iirev. 
U iim the tir^-t tiiuleiK y to point was orite displayed, 
metl, M-lectinn and the inherited effects t,i ('urn- 
puUory training in each successive freneratmn «.iuld 
-oun complete the work ; and uncon>cious >election is 
-till at wnrk, as eadi man tries tu pro<-ure, without 
iiitcn.iin:; u. impnnc the hreed, doirs which will stand 
.ind hunt l.cst. On the other liand, hahit alone in 
some cases has surtice<l ; no animal i> more diUicult to 
tame tlian tiie yoinijr of the wild; scarcely an\ 
animal is tamer tiian the yi^nui: of the tame r.Vl.bit'; 
!iut I do not suppose that domesi.;- have ever 
i.e.n selected for tameness ; ;,nd 1 |.r(-ume that w,- 
mu-f attnhute the whole of the inlierited chaiiire from 
extreme wildnesti t(t e.\treme tameness, simply to hahit 
and loiiL'-continued close confinement. 

•N'atural instincts are lost under domestication: a 
n-niarkahle iu-taiice of this is se«-n in tho>e hreeds of 
t'.^U which very rarely or never hecome ' hroody,' 
that is, never wish to sit on their eiTirs. Familiari'tv 
alone prevenU our seeinir liow u!ii\ ers.allv and lar-ielV 
the minds (»f our domestic animals iiave l'.een moduied 
I'y d<.mesti<ation. It is scarcely possihle to douht that 
th.- Im\,. of man has hecoine instinctive in tlie dofj. All 
wol\ es. foxes, jackals, and species of the cat -eiius. when 
kept tame, are mo^t eatfer to attack poultrv. -heep, and 
piu- ; .ind this tendency has heen found 'incurald.- in 
d..j-s which have heen hrouL-'lit home ;t> puppies from 
'•••iintries,such a- 'i'lerra del i-ur-o an<J Australia, wliero 

the savaiTi-s do not ke=.p t}-.^.- ,^,,,^^^.^,\,, a;:i:;;;.I-. How 
rarely, on the other hand, do our civilised d(.irs, even 
«iien .|uite yountr. re.piire to he tau-ht not to att^Hck 
poultry, sheep, and pi^'s ! No douht thtv ot-casionally 



<lo makf ail attack, and ;in' tin n Jicatfii ; ;iti(| if not 
curtMl. tlx'v aro <lo<;t royt'il ; «o that li.iSit, witii somo 
dfLTc*' of sclfctiriii, lias prulrii.iv '■((!H 'irrcil in civilising; 
by iiili«'ritaiicf' oiir (lo;/>. < *n the ntlicr liaiid, voutiij 
cliiclxcii- Iriv c iost. \\liii!l\' hy lialut . fliat f»'ar of tlio do:; 
and cat \\h:ch no dnul>t «as (iriirij'-illv in>-tinrli\(» in 
liu'tn. in tin- same wa\' as it is »(» |ilaini\' iii-'i!!c*i\-f in 
yoiiiiL'' jilica-.i!/-. Mn'Mi.'^h ri'and iihdtT a 'icn. it is iirtt 
that chi''l\<'n^ lia\c ln»t nil toar, hut ft-ar niilv of doL's 
and cat^. for if tlic ht-n i;i\<'»s tlii> daiii:''r ( Ii'ickli", Mu'V 
\\i!i r-ni (nnrc f-pc'ir'.lly vhiiii^ tur'i'\-i from undor 
lior, and cuncfal tht-rn--' 1\ c^ in tin? -urii'ijtidin:,' irrass or 
t)iicl,rt>; and thi~ i~ «". idt'nti\- done t'nr tfic ui-tuicti'-'o 
[iiir[iii»i' ot;il,'o« inj;. a-i vvc ^cc m w '!d :.'f>>iind-t>i:ii-.. their 
nii'tluT !<• tly awa\-. I'ut tlii- !i-iin> t retained h\- our 
eliicKeus h;is In cnnio u-^ele--- under di'ine-tica' iiei. tnr tlu' 
Tnotli>'r-hen lia> alnmst l(,~t h\' di-i-e the power ot (liirht 

Hence, we may cMiicIude. that domestic instintts 
lia\e heen acijnireil and siatnral instincts ha^e heen lo<t 
partly hy hahit, and ]'i' ly hy Tiian >(dectin; and 
accuiini!a*in_'^ •iurintr succes>-i\e t'c'icration^, peculiar 
nieiital liahi'.- and actions, whi(di at t'r-t "'red from 
what v\-e inu--t in our iirnor.fice (m!1 an ai cidiMit. In 
-orne ca<es roriipMlsory hahit aio-ie has -iif'iced to 
produce sutdi inherited men' il idiai;::es ; in oilier cases 
roiiipiiUory hihit ha< done nothii-.r. ami all has heen 
the result of se]e<-tion. piir-ned hrih methoijicilh- aiid 
unconsciously ; hut ir miwt cases, pro)iahl\-. hahit and 
seleclion ha\e acted |M_ellier. 

N\ e shall. periia]>s, hest nn h-r-'nid lio'v iji-t nets in a 
stale of nature have hecoiiie ni..ditied i>v -elc tiin . hy 
coM-ideriniT a fen c ises | wili selec* ouU three, ret of 
the sc'cra! v^l!■cll I sli.i'! ha\ e lo d -■ !,-s in my luture 
\\'>i'k. nanitd\ , tlie instinct \vlii(li h' ul- the i uckoo to 
lay her eL'':s ni other hirds" nests ; the slave-makiris; 
instinct of certain ant< ; and the comli-makiiiir power ot 

tlie hi\e-h'.'e ; thi'se tw'i hittev iiistiei'ts h;i\ e i''ene!">!lv. 

and most justlv. heen ranked tiv naturalists as the most 
wttndertul of all known instincts. 

It is now coinnionlv admitted that the more im- 



Di'diate and Mnal raimo of ttio nirkoo'<« irmtinr* is, that 
■<lif lay« her '•>rirs, not daily, hut at intorval-J of" two or 
t}irt'«' davH . so that, it" she were to inakf h»'r own tioxt 
and -iit on licr own otfi;s, thoso first laid would have 
to he lef> for somt' tir7U! unmcuhatcd. or liu'n* wmiM h*" 
•■rtrs and yonnL' hirds ot' dificront airt's in tli»< -aTnenftst 
It tills w(T«' tilt' .as*', thfi nroccs.- of layiriL'arul hatriiitij; 
nn^'-ht ho incoiivtMiiciitjy ion;:, inoro t-fit'i'MJlv a- sh«* 
has to niiirrate at a ver\ parly period ; and Mm^ tir«t 
hitched yonntr .vould j)rohai)lv have to he fed hy the 
male alone. Hut the Ainencaii nickon is in' 'his 
nrediriment ; for she makes her own ne<.t and has etru'" 
md yoiitiL' s^^(■|■e^slvoly hatclied, all at he -ame tirno. 
It has heen asserterl that the Amen. an ruckoo oe- 
casioiially lays her Oirtrs in otlier hirc|< ne^t^ ; |„]t 1 
hear on the hiirh authority of 1 >r. I'.rewer. that 'hisJH 
a mistake. Nevertheless, I eould yive ^.ev.'ral instances 
i»t various idrds uhnii liave heen known oecasiojialiv to 
lay their ejji-irs ;n other hirds' ne^ts. Nuw jet ns supposo 
that the aneient protreuitor of our Kuroj.e;.n (•'ickn<, 
liad the hahit<< of the American ( uckoo ; hut that 
"cca-ionally slie laid an e^^t: in another t.ird - ne^t. 
It the (dd lurd profited hy this (na-asional hahit. or 
f t!ie you ntr wore made more vitroroijs f.^■ ad^antaire 
'lavint: heen taketi of the nii>taken maternal instinct of 
■mother hird, than hy their own mother's care, en- 
. inhered as ^he can hardlv fail to he hy ha\ inu"- e^-'irs 
iM'i younir of" different a^'es at the winiotime ; then the 
Old hirds or the ftwlered youiiir would train an ad- 
■>anta:.'e. And analoiry would lead me to hel:eve, that 
'h.' voijTif thus reannl would I'O a[.t to toilt.w hy 
nheritancp the occasional and alierrant hahit of their 
'iKjtiirr, and in tlieir turn would 1)0 apt to lav t !:c:r ei'-rn 
in other iiirds' nests, and thus he successful in n ann>f 
t!K'ir youiiix. l>y a continued proc»'>s of this nature, I 
I'elieve tiiat tlie stran-e instinct of our cuekoo could he. 

and ll.'K liixitl trti, ,,,,-■,*,, A I r>. I.I ll ..1 „ . .1:. _ 

to i >r. (iray and to some otlier oh-cr\er>. the l-.urope<an 
cuckoo has not utterly lost ail m.iternal luve and i-are 
for her own offspruig." 



'Hie orcasional hahit of hirds layiiiff their eetfs in 
otlicr l»inls' nests, either of the same or of a (iistiiut 
specu'-t. is not very iiiicoriiiiHui with the iialliiiaceie ; 
anil this perlianx explains the onirin of a sinjfular 
iiistiiK 1 in the allieil trmup of o>trn hes. F<»r neveral 
lien o-itrii lie-;, at h'a^t in tlie ia<e of the Arneriran 
sjiecies, iirnlf' au'l lay ti^^t a few et,'i:- in one ne>t and 
tlieii in another ; ami tlie-ie are hati lied hy the males. 
'Hiis ui«':nr! rii.i\' |irof>.il>lv Ixi arcounteil lor hy tho 
fact of tlie hens la\ wiiT a lar^'O niunlier of ej-i^s ; hut, 
."is in the <a-e ol the nitkoo, at inter\al» of ^wi, ur three 
(lays. Thi- in«tirii't, howescr, of the Arneriran o-trirh 
tia- not as ytt I.een perfected ; for a surpri^iui: fiumher 
of e:.''j;'« lii' str«'v*«'il over tlie plai.i>. so tiiat in one day's 
hiintini,' I pu;ked iiji no less than twenty lost and waited 

Manv lK»es are para>itic. atui alwa'.'" lay their e:ri:s in 
tlio n.'sfs of liee'4 <it other kinds. 1 his case is more re- 
niarkahle than thai of the cuckoo; for these hees have 
uot only llicir instincts hut their structure moiiifird in 
accordance xvith their jtara^ilic lial>;ts ; for they d-t iiitt 
possess the {lollen-ctdlectinir apparatus which would ho 
neressarv if they had to store food for their <i\»n vonn;;. 
Some species, lik»'wise, (»f Spheijidie (wa-ji-like in>ects) 
are parasitic on other spci-ies ; and .M. I aine h^is lately 
sho" n iTood reason for iK'liexini; that aithcniirh tho 
lachytes niLTa jrenerally makes its own hurrow ai<'l 
stores it with paralysed prey for its own lar\a» to feed 
on, yet that wlicn this insect tinds a harrow already 
made and .stored hy anitther splie.x, it takes advant;ufe 
of the prize, and i.ecoines for the occasion jiarasitic. lu 
this c;ise, as uith the suppiised case of the cuckoo, 1 can 
see no difhculty in natural seh'ctioti making' ati occa- 
sional hahil permanent, if of advanta;_'-e to the species, 
and if the in>ect who»e nest and stored food are thus 
fehtniously approjtriated, he not thus exterminated. 

Sltive-rtinking inxtinrt. — This remarkahle instinct was 
first discovered in the Formica (I'olyertres) rufesceus hy 
Pierre Hiiber, a In'tter observer even than his celebrated 





fatlior. 'ITiis ant ig sVisolutcIy dependent on its slaves ; 
without their aid, tlie species would certainly f>e- 
come extinct in a hin^fle year. 'Hh' males and fertile 
females do no work. The worker^ or sterile feniaU-*, 
tlmiiifl; most eiierjfetie and couraireous in capturitij.' 
^I.l\es, do no otlier work. I'hey are incajiahle of mak'nt; 
their own iirst.s, or of feediiiir tlieir own larv*. \V hen 
the old iiest in found inconvenient, and they have to 
III if rate, it i.-i the slaves whicli determine the mijfral:on, 
and a(tually carry their m;ist«'rs in their jaws. So 
utterly lu'Ipless are the ma«ter«, that when Holier shut 
'iji thirty of them witljout a slave, hut with pletity of 
tde fond which they like l>est and with their larva? and 
pii|»ie 'o stimulate them to work, they did notliinir ; they 
rrdild not e\en tied themselve.><, ami many perished of 
• lunirer. Muln-r then introducer! a siiit'Ie slave {V. 
tii<caj, and she instantly set to work, fed and hiived the 
-i.r\ Ivors; made some cells and teudtd the larvip, and 
jilt all to ri::^lit«. What can he more evtraordinarv 
tiiiii tlu'se w»'ll-ascertaine<i lacts.- If we had not 
k:: iwn of any otlier slav»>-makin{; ant, it would ha e 
Ihi!i hop«'le-.s to have sjteculated how so wonderful an 
in-tinct could have been perfected, 

.VtiotluT .-pei:es, Kormii'a sanyuinea, was likew'se 
tir-t discovered hy I'. Huher to he a (ilave-makiiiir ant. 
Ihis '-pecies is found in tlio .southern parts of Knirlartd. 
i'.n\ its iiahits liave iieen attended to hy .\fr. J . >!i;ith, 
"' tlie llritish Museum, to whom 1 am mucli imiebted 
tor inforination on this and other suhiects. Althout:h 
fullv tru^tiiur to the stateiiiefit.s of Hut)er and Mr. 
>initr;. I tri<'d to approach the suhject in a ■weptical 
fraiiie of mind, as any on'- mav well he excused for 
'iouiitinjf the truth of so extraordinary and odious an 
:i-tiiul as tliat of makiinf ^ia\es. Hence i will jfive 
•he oh-ervalions which I ha'.e myself mrole, in sonie 
':tth' detail. J opened fourteen nest,s of F. -arnfuiu'a, 
I'iil toiin(i a fi,''w slave*^ in hII. Males and fertile 
ri males of the slave-specie.* (F. fusca) are found on'y in 
'h* ir own proper commu'iitie-, and have ne\er been 
ol-ervt-d in tlie nestH of F. -.uiiruinea. Hie slaves are 






Mark Jiiul not atiovH lialf the si/« nt tlifir ro<l masters, 
HO that ilie Kiiitra.'^t in tlu'ir ajiprannct' is \«Ty ^'reat. 
Wht^ii tlu' in'st iM hliirhtly liii^lurtted , tlip slavi'H orru- 
Hioii.tllv «iim(> out, niid like thuir ma«it<'rH ar«« nim-h 
aK''''»''l and di'tcnd tim in-st : uhcii rli<« iip^t is mucli 
ili«tiir!«;'d and tiji' larv* ami puji^ arc <'\|>iis(.(l, fho 
«la\»'s \T(irk ♦'ufi-L.-fM ally with their tiia-tfrs in carryirnf 
tln'iM aw, IV tu a jda.c ot s.iloty. llcnri-. it is «lcar, that 
the slavf. trvl <|uite at lium*'. Duriii,' the riiKutlH of 
.iujM-aiid ./illy, t>a tjiree Hiicces'-'ive year-. I have watched 
fur many hours neveral ncst.x lu Surrey aim >u^«iex, and 
uever saw a slave eiili.-r leave or enter a ne-t. A.x, 
'lurm^ these montlis, tlie are very few in nufiiher, 
1 thoiiulit that ttiey Miitrlit helia.e dilterenily w h»Mi 
(iiore nimp'MiiH ; hut Mr. Smith informs ine that li«' han 
i*atilie<l i.iie nt'>.ts at various hours diirinjr .May, J .lO 
and .\utrusl. 'Mitii m ""urrey a;i<l llaiii).-(iire, an<l ha.s 
never seen tiie ^la^es, thout;Ii pre-ent in larue nunih«Ts 
in Auu^usl, «-ither l<'a\f or enter thf ne^t. Henee he 
considers tjir-n as strictly h«Mi«.«'hol(i Hlaves. I he 
mast<Ts, on the other lianii. may ite <onstantly seen 
hriiiuiiii^- in n.aterials for the ne^t, and fo(.<l of all 
kinil>. i)iirint.' the present year, however, m the 
month of Jiily, J came across a lornmunity with an 
unusually ]ar;;e sto. k ol slaves, ami I ol.-cr\ed a tew 
blav. -- iriiny-le<l with tiit-r nia.stur» loavuiLT tin' uc-.t, an<i 
mai. in m niov)/ the Name r(K»tl to a tall Sc(.t. ii lir iree, 
twenty-iue yards disuml, which they ascended to- 
ifother, pr'i'>ahly iu se.'jrt h of apimles or cocci. .Ac- 
corduiK to lluher, who had amide opportunitie.s lur 
obberyation, in Switzerland the slaves h'ahitually wnrk 
with their iiias',fr> in niatcinL' tiie nest, and thev alone 
open and clo-..' the doors in the njornini: an! e\enin^'' ; 
ami, as lluiK:! r\pre---ly Htate«, their j.nmi[»al oifice is 
to --e.irch for .iphidcs. 'i'liis ditference in the usual 
hahits of the masters and slave-s in the two tountrii-s, 
prohaidy de|>ends inerclv on the .slaves beinj.: cantiired 
iu jfreater nuini»ers in Swity.erland than in Kiiirland. 

t>noday 1 fortunately witiuvssed a mipratiou of F. 
sanruine.i from one uest to auotherj and it wa« a most 




iiiT»«rPstin<f spert.iflo to U'hnld tlic mn^tprs rarofully 

t a: ryiii;; (iii«u .1(1 uMM'iiik'' (".•irrifil l>y. as in \\\i- <m-«» <if 
' riifesriMiH^ tlu'ir •'In fs ill tlieir jaw^. Aimrlii-r (l:iy 
:.\ attf-iitioii wa■.^lrul•k liy ahout a -coro ot tin* -l.ivi»- 
: . iki'iH daiitititiL' till' s;iine -[! csiiirntlv iiol it) 
searcli (»t f(H)(l ; tlioy a[>jir«iarlM'il a:iil \vt>rt' v i:.'nriiu*ly 
r»'jiiilse«l i'v an iiiii»'|>«Mi(lciit ciiiiiniuuity i>t' tin- »laM'- 
sjH'i'ies (F. lU'ca' ; miiik^ a> inan\ a-. l!iri»«' of tln-^e 
aitt,«» cliii^''tnir I" ili<- IcL's of ih.' -1 IV <»-m:il\i;ii.' I'. *sni- 
^•iiitioa. Tii*' lattiT riitlili'silv killcil tln-ir »;iiall oj>- 
poiitMiN. and <arrit'<i tlifir dt'ati ImmIjw .is (<mh1 to th»*.: 
n.'st. t .*oiity-miie yanl- (ii«taiil ; luit liny acn* |m»>- 
\fiiU'ii iritm LM'ttiiii^ aiis- |>ii|i;flo r»'ar ai slau--. I then 
tliii; ii|i a -inal; panel of Mn* |iiip.c ol I. fii-^'a from aii- 
o'luT rii'-t, .mil |iut tiiffti (liivvii on a Imiv -i>«tt iit'ar ♦))»• 
iihii I' of roiiiiiii ; tln-v were ra^'iTU' ••fi/»>(l, and <'.irri('<i 
olF I'V tin* tyrant . «li() j't'rh.ijc raiirit-il tliat, at\fr ill. 
liu'v had hi'tMi \ u'turioii- in thi'ir lato coinlial. 

At tiic <ini • tiiiK' I laid on the same jdai-*' a «imail 
[iar> I'l of the |)iiji;»' of an«tt!nT mju'iIps, K tl.iva, vsith a 
f>'\\ of these JMtle yt-llow ants ^tiIl fliii.'iiic to the fnitf- 
i ;rn'«. of the nest I iiis speeies is .^onii-times. thmnrh 
'•i'"i'i\-, rnailo into -!aM--, as ha* heeii de-<cri''e(l t.y Mr. 
."^i.i.'h. Althoiitrii so siiKill a spcnes, il is very lour- 
au'MMiSj and 1 iiav«« •-e<Mi it fer(»eiou-ly attack other ants. 
ill I'liO iii-tanee 1 found tu my surprise an indepeiident 
lommnni'v of K. Ihaa iKiiier a sto.-ie heneath :i ncst of 


deiiUUy disturhod hotli Hitst^, the little atits af.i> ke« 
♦i:-'ir hi^ neiirli'Miiir.s with s>,-j,ri-ini?- «*oura.'(«. .Now , 

tilt? slave-'iakinu F. satitruinea ; and when I aeei- 

- lurious to asiortaiM whether F. santrmn»»a <oiild 
liisiiiimiish the pupa' of F. fii-ra. wlii 'h they hi!''; 'lally 
make in'o slaves, from those <»l the little and h.iiims !■■. 
t' vva, which they rarely <a]it(ire, and if v\a.s evidejit 
•' '' t' f\ did at once distniirui-h thi'iii : for we lia\e 
r en that tliey eairerly and in-Liiiitly seized the pup;** of 
t. lusra, \vh»*rt>a.s thev were much terriiied when the\ 
came across tin pi:p*, or e\'>n the earth from the nest 
of F. flava, and quickly rau away ; hut in ahout a 
•quarter of an hour, shortly after all the little yellow 






arifx li.iil <T.-i\vh'il .iway, they took heart and rarrie*! 

off tllC Jll||»>»*. 

( )rie ineiiiii;/ I v i-iltd another <(»uiniiinity of K. <«u- 
iT'iiiiea, atiil toiiiid a iiurnher of th('-.e aiil>< returiii!!^ 
hoiiif and eiit<-riiiir tln-ir in-t«, carryn;; the dead Kodi""* 
of K. (ii^i-a (•.hov\ ill;.' that it wa.x iiot a aiiif ration) arui 
iiiimrruii.4 |iiii>;e. I trari'd a l<ni;f hie of aiitx hiirtheiieil 
willi iioiify, Iiir ahoiit tnrty yards, to a \ervth;rk <liirn|i 
of heath, v*lii'tice I -av the hi-^t indiu' (if K. phu- 
iriiine;! eiinTirt", <arryiiiL' a pupa : Imt I ua^ not ahle m 
tiid tlif (le-ulatfd iie>.t in Mie thii k htatli. Ilie nc-t, 
howf^iT. inii-t ha'.e h»'en ehxe at h.ind, fur two 'ir 
thrt'"' imliv iduaU of I', tii-ra were rii-ini.c ahoiit ni t)ie 
crealeNi .itritafiori, and one wa« jM-rched iriotioiih'^- .v;*ii 
it* iiwn pupa iti iLs rmnjt h on tlio 'op of a '■prav of heath, 
an iiii ci'e (it de-pair, over its ra\aLre(i home. 

N'i( h are thi- t.icts, thoii::li thev 'iid not need con- 
firrn.ition hy nie. in reiT'ird to the udndcrful instinct of 
iiiakiritr sla\t>-. I>'t it he oKser\-ed \v)iat a cdntrit-t tlie 
instinctive liahits of \-'. s,iiiiruiii,.;i present wit!i those of 
the K. riifescci s. The hitler does not huihi 
its o'Aii lies!, dues nut determine its own micralions. 
i|ii('-< nut coiicc; i.iod for ;t>elf or its yoini;.'', .iiid (.iiiuot 
e\tMi feed it-cif; it is ahsolntely dependent on its 
iiiiTiieidiis -l.tx,.^. I'oriniea s.ini;iiinea, on th • other 
liaii'!, pn>.v,>v.(.^ much fc\N('r •"laves, and in the early 
part (it the summer extrcmeh few : tiie ma>ters deter- 
riiMie \\]f]\ and wliere a new -hall he formed, and 
when tliey mi:.'-ratf. Mio m.i^ters cirrvtlie >lave-i. HoMi 
in Switzerland and IJiLrland tlio -la\es -cimm t(i ha\o 
the exclusive care of tlie lar\.e. and tlie masters alone 
•Xi^ on •.j.ive-makinir expeditions. iti >»;t/.crland tiie 
slaves and ma-?cr> work tdtretlier, ni.ikii./ and hriiiijin;; 
materials fnr tlic ne^t : Iiotli, hut chieliv the >laves, teiul, 
and milk as it m,iv he calleil, their aplmic- ; and ihu.s 
lifitli colle('t food fur the community. Iti Knirland the 
!oa>ters ahme u-u.illv leave the nest to collect huildini; 
fiiatcriais.iiHJ ioo(i for I ii em -fives, tiieir slaves ;inii iarv w. 
So that the m.i-ters in this country receive nuich !e<»« 
service from their -slave« thati tliey d«» in Switzerland. 



Bv what nicy* th»' iii-timt ot F. •wiinfuiiiea oritriii.ite<l 
I will not preU'tifl to roiijertiire lint ax ;uit-, which 
irr 'lot il^vcv-niakprx, will, a« I li:i\ c mn-ii, carry orf 
liii|i»» of otli«»r •i|>«'(i»"*, if xcatt^'HMl ru'ar tlu'ir iirst-, it 
M |»o»j*iliU» tliat ■•Mcli ]tu]>if nriifiiia'.ly sturiMl iw tiimi 
mikrht IxM'onift d«ni'I(i|M^il ; ami the fun-icn ants tlni«* 
uiiinteTition tliy reare<l wouhl then .'nll.r.v tlii-ir proper 
.U".tiiict.H, ami <lo what work tlu'V rouhl. If tht'ir 
liri'seiire proved useful to the 'iji»>«it's whu li h;nl •••i/»'<l 
•lu'm- if it wi'TO iiioro advantatfrou-i to this s|»rii»'s to 
rittturB workers than to jinnreate tliern the hahii ot 
' 'ilectinj; pup* oriirMially for food iniuiit hy natura' 
-rlertioii ht ^Vrt'iiL'thfMO*! atnl rendereil pernianeiit Tor 
tiio very ditferent purjio^e of ni-^iiijf slaves. W hfu the 
iii-itinct wai* once acijuired, if larried out to a nuirh 
If- exrerit even than in our itritinh I'. s.uuriiioea, which, 
I- we have -^eci, ii less aided liy it>i »la\ es than the s-itne 
«pe'ics in Swit/erland, 1 can -lee no ilit'ii t;lty in na'urai 
>.dectiou increasintf and modifyinj; the insti-ict — alwayt* 
"Upposirij; pacli nioditicatioii to he of use to the specie^ 

•iiitil an ant vas formed aw at>jectly dependent on iU 
-la>cs a.^ is the Formica rufesceus. 

I'fll-innking in*t\iirt oj tK»- ihtr-Hrr. — i will not hero 
•liter on minute details on thiM suhject, hut will merely 
j-ve an outiine of the con.dusion.s at which I have 
Arrived. He must he a dull man who can examine the 
exquisite ntructure of a comh, -o KeaulifuUy »<i ij>ted to 
Its end, without enthusia>tic adtniration. W e hear 
rVini mathematicians tliat l>ees have practically <oi^ ed 
I recondite pri.hlem. and have made their cdls of the 
inHpcr >lia{»e to holil tlie trre^itest po>-sihle amount of 
liotifv, with the lea^l p«»s>i!de consumptinti of precioui 
wax in their con^tructuni. !t ha- Iteen remarkf'd that 
a -kiltul workman, with tiltir;.' tools and measures 
would tinil it very difficult to make ceils of wax of the 
true fnrm, thonuh this is juTfectly etfected hy a i-mwd 
ot hees working in a dark hive. (irant whatever 
instincts vou please, atjd it seems at first .piite incon- 
ceivalde {low thev can make all the neceHSiiry aujfles 



aii'l planes, or oven jK-neive whoii tiiey are corrtctly 
m;i(lo. JWil tlii> iliilicully is not nearly ^■o tfreat as ii at 
fir->t apjK-ar^ ; ali tlii« [)»Mutifiil work can l»e shown. 
I think, to foll'^Aiioina luw very eiiiiojc instiiici.-,. 

1 •vas lf(l to invesiii.Mtf this siilijcrt l)v Mr. ^\'at»'r- 
h().iM', i\lio has .sliov*n tliat the fonn of tlit' ceil staml^ 
111 ilo-c oil to ;lie jirt's»>iit i* <tf :ul;oiriiii;,' ccis; aiwi 
tho following; vitMT may, [(.'rhaps, he i (tii-ul.Tcii only am 
a iiiodifiialxoi of' h;. tiicory. I^-r us- jo.ik to tlie tc'ri-al 
l>rirn'i|)!t. .,; m i.iiUon, and ^cr uheUu-r Natii.-c does 
not reuMi to ui iier ni»'tho(i uf work. \- fod o?' h 
b.'iort scrie- we )ia\o liu?iiMe-tM'e>, HJii.ti u^i- the:rohl 
rocoons to lodd honey, -urneliinev adding' t<» tlu'in s'nort 
tiihe-^ ot Ma\, and lik".\:M- miikio:.' -.-ii. irate a;iit \ery 
irre^^ular nouKii-d c-Ils .,:' wa.v. At the other end of 
the stiries «.- hav. Lhe .ells ol the hi\t-''e!', |.!;ii d in a 
douhio laxor: e.udi cell, as is ucU - known, is .an 
ln'.\.it:onal [oi-m, wit), tti..- hasal e-ltres oj' its si.\ r-ules 
h«'v»'lh'd so ;..- to lit oij to a [lyramid, formefi ot three 
rhoMihs. 'J'lio,-- rhoinh.s h;i\i> lertairi an-les. and the 
tiiree which toi,ii ihe i-yrainidal h.ise of'a sintrlc ccH on 
o!u> side oJ tlie com*', enter into the coniposition ot the 
li.ises «d thiet; auium'ii;; cells oii J' e oioiosite side. in 
the ser.ox in tween the e.vtreine |»erA'ciion of tiiectdls 
o,* ti:e hi.e-heti aud tlu- siruidicity ot thi->c „f the 
hiiinhli, «f ha\e tile cells ot the" .Mexican MiMjioria 
domwjLic^, carefully tlescn!>ed and tiuMuctl h\ I'lerre 
Huber. 'J'he Midijiona it.self in iiiterniediate in struc- 
ture hetvTm-n the hive and liunible iiee, hut tntoe n'-arly 
ris'ated to the latter: it lunns a nearly regular waxen 
cooih of cylindrical cells, in which the youni^ are 
hatched, and, in addition, .some lar;.'^e cells id" w.i.x for 
holdinir honey. 1 hese iatler cells are nearly spheruai 
ao.l ut nearly cijual .--izes, and are a^'^^jrc^atcd into an 
iriciTular Mias-i. Mut th(> nnjiortaut iioint to noti;'e, i^ 
that till so celN are always made at that de^rree of 
nt-Hirne-s to e.icli ntluT, they would have intersected 
or t)rokeo into each other, it" the spheres had heen com- 
pleted ; hut thi^ IS never permitted, the In^es building 
perfectly flat walls of wax between the spheres which 




'Jnis tend to intersect, fleiico each roll consists of an 
• iiitfT spherical jM)rtiou and of two, three, or more 
[)t'rtertly Hat Mirtaces, according as tlie o«'ll .Kii'-nirf 
two, lhnt,\ or more oihrr d-ll.-. When one cell coniC!) 
iriio contact wiih three- ollicr cell^, *\hich, from tlie 
Vi.herc^ l)»'iriir nearly of the sanif size, is very frequently 
;i .ii nt'cer-^arily the case, the three liat .sur .i<es ar.- 
uiiiiea itit(» a |»vr;imid ; and tliis pyranmi, as lliiber lia- 
r-iiiarked, is iii:inik'>Hv a trross imitation of the thifc- 
s.aed pyrainiihii haesot the cell ol ttio hiv«»-l)ee. A* 
1! the ceils ol tiie hi\e-b«H}, -o here, the tliree plane 
SI. Places in any one <ell nccessiirily enter into the 
ci nstruction ui ti:ree aiijui/iinif cells. It is «/nvioun 
tiiai the Melipona skives wax hy this manner of I/Uililiiiff ; 
tir th»» Hat w.'iils hetween the adjoining cells are t.nt 
iliiilth', hut are of the same thickness as the outer 
s; uerical port:()ns, ai. i yet each ihit poition forni> a 
[)art of two cells. 

llcHectiiitj on this rase, it occurred to ine th.ii ii t:ic 
.Mdipona had m;ide it.s sytheres at fcome tfiveu il, stance 
from each other, and liad made them of equal sizes and 
had arrantred them symmetrically iti a douhle layer, the 
roultiiii: >tructure would proha'nly iiau' heen as [lerfcct 
a, the comh of the hive-hee. Accor<iiii^iy I wrote to 
l'(nf.--.or MiUer, or ( amhridire, and this ;:eoim'er has 
V mllv rea:i the follouini^ sLaU-n'Cuf, di.ifii up 
: om hi^ informadun, and tells me that it ia .-Lrutly 
.urriH t : — 

li a n.iml>er oi equal splieres he descri!r^l wiih their 
ci nircs phii t.-'i in two [)ai;iiifl layers; «ilh thu li ntid 
■ i t :u!j -j'hero at the disLanco of radius x ^' 2, or 
:\niis A l-ill-l (or at some h-sser distance), frurii the 
•xnlren ot the si.x surroundiim .^phereti in the .same 
hiyer ; and al the same distance from t!ie centres ul 
I'he ad'oinini; spheres iii the other arul pa.-allol layer; 
iht u, if planes (if Miiersection hetwefto the -e\ei<i! 
spliere.s in hoth lavers he formed, there will r-'sult a 
d<»ut)ie layer of he.xiuional prisms united to^etlier by 
pyramidal l>ases formed ol three rhomhs ; and the 
rhouilw and the Hides ot the h< xa!;onal prisri.r< -tui iia/e 



every nriL'le identically the same witli tliel)est measiire- 
montH which have been mude uf the cells of th»* 

Hence wp may safely coiiclMfle that if we 'ouM 
slicli'Iv rno'lify the instincts aln-afiy |k»s»ssp(1 l»y th»- 
MelipDiia. and in tlieniselves not vcrv wonderfiilj tlii^ 
licc wiuilrl make -j -tnicture as w<pii(ifrfiilly |>ertVct as 
t)i,it of the hiv>-hee. \\'e must suppose the Mdipona 
to make her cells truly sphorical, and of equal »i^rs ; 
and this would not he very surprisiiitr. sp«^niL' that -.he 
already doe-j so to a certain extent, and >oei!iir what 
pertectiv cylindrical hurrows in wood ruanv i[i*c.-Ls can 
fn.ike, apparently \r, •uminir round on r ''xed point. 
\\ e itiii.-t supp(»se the Melipona to arranre her cells in 
level layers, as she already does her cylipdrical ''idb : 
and we must further supjiose, and this is the t:reatest 
ditluulty, tliat slie c^ti somehow iudtre ai'curately at 
what distance t(» strand from her tellow-lahourer- wlieri 
several are makinjr tlieir srdieres ; hut she is alreaily 
-o far eiiaided t(, judtre of distatice. that she always 
descrihes fier spheres so as to intersect largely , and 
rhen she unites t.hp points of intersection hy perfectly 
?iat surfa. cs. \\'<. liave further to supjwwo/hut. this is 
no dithcjlty, that after hexatronal prisms have Iteen 
formed l.y the intersection of adjoinirnf sjdicres in the 
same laye-, sho can proloajr the hexaL'on to any len^rth 
re'jui>ite to h(dd the stock of honey ; in the sanu- way 
.T< the rude humhle-hee adda cylinders of wax to the 
circular mouths of her old cocoons. !lv such I'louitica- 
t.ions .(f in-tincL- in themselves not very rtunderful,-- 
liardh more wonderful than those winch truide a 
t>ird to make its n^'st, — I htdieve that the hive-hee 
tia^. acijiiired, throuirh natura. seleition, her iriimitahle 
arc}i't('<'tural powers 

Itiit this theory --an he tested hv experiment, 
(■■.dl.'wiiijr the example of Mr. leiretrneier, 1 separated 
two coiiil.-. and put hetween thetn a loiiir, thick, siiuare 
trip of wav : the l>ees iiistiintlv he^'^an to excavate 
niinhte circular pi*s in it ; and as they de«'pened the-^e 
little pit'^, they uiade them wider aiid wider initil thev 



were couvert»'d into shallow basins, app«*ariiitr to the 
eve perfectly true or jmrts of a spher*', and of about 
the diameter of a cell. It was most interestiiijr to me 
td t>twerve that wherever several hees had detr'ni to 
<'\<\i>ate tliese ha>ins near toiretht-r, they hau be^run 
tiieir work at such a distance from eacli other, that by 
the time the basiiH had acmiired the above stated 
*idth (!.»'. about the width of au ordinary cell), and 
Aere in depth abnut one sixth of tbe dianiefer of the 
-phtTc of which they forme<l a part, the rini> of the 
ba>uis intersected or hrol<e into each other. As soon 
i.-^ this occurred, the bees ''eased to excavate, and 
lieu'".an to build up Hat wu!' of wax ori the line-; of 
'Mfer-ection between the l)ii.«uis, so that f;iih iie\,n.'i>nal 
;iri><in w.v> built ii[ion the scalloped eiij^e of a sinnoth 
iia<in. instead of on tlie str<ii::lit edire^ o; ;i three--ided 
pvrainid as in the ca-^e of ordinary celi-. 

1 then jtut into the liive, instead of a tliick, scpiare 
piece of wax, a thin and narrow, kinte-e<i_re(i ridire, 
coloured with vermilion. 'Jhe bees instiintly beiran on 
both -i.les to e.xcavate ! 'tie basins near ;o eacli other, 
in the sjime way as before ; but the ridtre of wax was so 
thin, tliat the buttons of the l»asins. if they had been 
excavate<l to the same depth a.s in the former experi- 
ment, would have broken into ea<"h other from the 
oj'po-ite sides. The bees, howe\er, did not suffer this 
to liappen, and they stopped their exca'.ations in due 
time; ■-•o that the liasin-^, a.«i soon as they h;id U«en a 
little deej)ened, came to have ilat bottoms ; and tliese 
llat bottoms, formed by thin little plates of the 
vermilion wax having been left untrnawed, were 
situ.ited,as far a.s tlie eye could Jud^'c, exai-tly aloriir 
the planes of imaginary intersection between the basins 
on tiie opposite sides of the ridije of wax. In parts, 
oiily little bits, in other parts, larire portions of a 
rhombic pl.-ite had been left t»etween the oppo-ed !ia-ins, 

l..,» ll... ,. .»!' i'>,.n, *\^n •< t<,.»».. rnl .£•'>»<> ■•*' »l,;>i.r^' l.irl 
■•■:-. .. J : T.- " .. -; r-. , : ! ** ::i • ii* . t t ■ • I't '. -.a Ftt t ^..,.» ... .,...._- ...... 

Hot been neatly performed. 'I'he bees ri\u«.t have 
worked at very nearly the same rate on the opposite 
side.-' of the ridfje of vermiliou wax, a.s tiiey circularly 



iriiawed awa\ and decpene'l llie basins on lK)th sidesj iu 
order \i< lin.o suci'oedcd in tlius leaviiji: fiat plate* 
hctwpfii flie lasiii-, iiy slojipinp work a'oiitr tlio intt'r- 
tnt'diat*' [ilaiies or pWuics ot iiitcrsoiti'in. 

( on-idcrinK ln'" i!«>xi!i!»? tliiii wax is, i d(» not -see 
tliat there is any diflirLlty in lli(^ Itcs. v^liilst at w<irk 
im tlie tuo sides ot a t^trip of wax, penciviiitr wlicii 
tlicv lia\'^ trii I'.u'd tlie wax away to the jimjicr tliinncss, 
•111(1 tlicn s^ojijiuic llH'ir work. In <i:diriary combs it 
ha- appi-arod to me t' tli»' bees do not al'-«ay8 Piu'i«'od 
m workiiiiT at exactly the" rate trnni the opjios-»(> 
hides ; for I have noticed ha't-comph'tt'd rhombs at the 
Itati- (if a iu-t-comnieiiced cell, which were slii,'htly 
< (incavc on one sidf», \viiere I suppose tiiat the ln'c^ had 
evcavate(l too juickly, and coinex on the opjiosed side, 
where the bees had "urktwl less (pnckiy. In one w»-ll- 
Tnirlcd iii'«t-'i!ice, I jnit the comb hack into the hi\e, 
and alhiHi-d the bee- t. e<* "'i workitiL' for a sliort 
time, atui UL'ain examined the cell, and 1 found that 
the rhi>nih:c plate bad lieen roni!'!eted, and bad hci onic 
pfrirftiij fict : it wius alisoIutei\ iiujios^-ible, fr<i!ii ihi' 
extreme tliinness ot the little rhombic i>late, that they 
« Olid liave elfected this by tr'i:i"'Mi;r away the convex 
side ; and I su-pcct that the bet"'' in '•uch cases staixi 
in th»( opposed cells and push and bend tlie ductile 
ftiid wai ii: wax (whicli as 1 have tried is easily done) 
intit its proper interniediate plane, and thus datten it. 

I'rom th(3 ei)>eriinent of tlie ridi^c of \'ermilioii wax, 
we ( learly >ee that if the bees \*ere to liuild for 
thenis(d\f- a thin "all of wax, tlu". co'ild make their 
ceils tif tlie jiroper sha|'e, by staudiiii; at the |irop«'P 
<listance from enli other, by ext avatiiiu'' at the .s^inie 
rat.', and by endeavourinij to make et|ii,il spherical 
hid'owv, but ne\cr allov.ini'- the spheres to 'oreak into 

each o'her. Now bees, as may be eh--irly seen by 
«-xaininiii:r the ed^'^e of a growintr comb, do make a 
ruiiLrh, circumferential wall or rim all round the ( omb ; 
■iiid they ^iiaw into this from the 0]>p('-ite sides, always 
workimr circularly a.s they deepen each cell. 1 hey do 
not make the whole three-sided pyramidal l>ase of any 



oiiPCf'li at tho s.-ipif timt'. hut only tliPone rhomhic plate 
which stands on the extrrmo ^rctwin? marifin, or the 
two jil.'ites, a- t)it« case inay i'o ; aiu! thev n»'\er loin- 
jilfte t'lM' iipjier e(li:'*< ot" the rlioiii'iif |,Iato<. 'intil th»' 
Iie.\a:.'(inal walls arc tntntnem-pd. Norno <»t tln'x- >tatr 
iiirnts (iiifcr from truo- inaiU' by tlio iu>tlv celcliratrd 
cMfr Muher, tint [ am lOininred of their accurary ; 
ai.ii if I liad >[ihcp, I couM -Ikiw that thov an* rniifurm- 
alilt' willi my tht-ory. 

Hiih«n's statcnit'nt that the mtv f;r<t (•«'ll i^a 
I'vcavatt'd f)iit of a litll»» jiarailol-'^iiiffl \vall of wax, \a 
ji'it, as tar as I have soeu. strict] v i-nrrert : the first 
t .'inirK-ncenuMit liaviriir alwav- hecii a littlo Jiooil of 

wax ; hut 1 wili not liere i'-.-.U'v on these de'ail 


scf liow irniuM*'"* a part excavation plays in the cori- 
-tnictidii of til' s; hut it wn:ild ho a (.Tcit »Tror to 

>!ipp<',(. tliat t'l H es caiuiot h'nld up a rouL'h wall of 
v*a\ ii! the proper position- (hat is, aloii_'- tli'' piano of 
intersection between two adjoininjf Hpht-res. I liave 
-'"MTal '^pet-imens sliowinir clearly tli it tiiey can do 
tfiis. K\en in the rude circumferential rim or wall of 
«ax round a trrowin-r iMmh, tlexnres may sometimes be 
(■'i-crved, <orre^pondini.r in |)ov!tiii!i to the phines of tlie 
riiomhic iia-al plates of futnn- rell<. Hut the rourh 
wall of wax h is in evory ea«e to he finished oif, hy 
liiin:: lar^'ely ^'iiawed aw.iy fn Imth >!iies. The ni.iuneV 
ill ^\iiich tlie bee- build ;•* curious; thev alwavs make 
ti:i' first rou^rh wall from ten to twc-itv tinn's 
tiian tlie exce»ivelv thin lini-lied wall of the cell, 
xvhich will nltim;itely hi' left. \\ e -Ii ill understand 
hnw they work, h} suppo-iiiir masons tn--t to pile up a 
hroail riiiire of cement, and then to he:; in cuttinir it 
away eijially on both side- noar tin- jro'ind. till a 
-loootli. \cry thin wall i~ \vl\ in tl,,- rniddle ; ihe 
Til i-on- always pilinjr up the cut-away cement, and 
aiiiliiiL'' fre-li cement, on the summit of the riflire. W'e 
-hall thus liave ;i thin wall steadilv trrowinir upward : 
l>ut always « -owned by a ^'ij^antic copin;r. From ail 
tlie cells, both those just commenced and tho-^e com- 
j>leted, beinjr thus crowne«i by a stroujf copinj^ of wax, 




the Jices ••an cluster and crawl over tlie comb without 
injuriritf the delicate liexairoiia! -.alis, which are only 
about oih; rdiir-luindredth of an Mich in thickness; the 
(dales of' the j)\ ramirlal h.isis \,c\ui: ahoiit twiie as 
'.hick. Ily thi- sinirular manner of huildinjr, strerifrth 
is cditinually u'ixen to the conih, with the utmost 
ultiTiiat«> e«-oiiuiiiv of wax. 

it -eenis at rir^t to a>\ii to the dJIIiniltv of undcr- 
staiidiiiir liow tiie vrUy. are made, that a multitude ot 
bee- all «ork r(i::.'thcr ; one hee after uorkinyr a <h(irt 
time at one c(di ircdnir to anotlicr, mi that, as fluher 
has <tareil, a seore of individuals work even at the 
. omineiicerio'iit of tlie fir>t cell. I was ahle jiracticallv 
to >\ut\\ this fact, hy coverin:: tlie »'di:.-> of rh'e 
hexajronal walN of a Kin<:le lell, or the extrcnu" marL-in 
of the circumferential rim of a urovMnt: <-(iinh, witli an 
evtiemtdy tiiiii layer of melted vermiiion wax ; and I 
iinariahly found tlial tlio colour was mo>t (Iclicately 
diffll^ed l.y ttie hees -as deli.-ately as a painter could 
lia^e d(»ne with his hru>h hy atoms of the coluured 
wax havini: hiM-ii taken from tlie ^jiot on which it had 
been ]ilace<i, and worked into the trrowinif edtrt's of the 
cells all round, 'i'he v< ork of construction seetiis to bo 
a sort of balance struck between r7iany l-ees, all in- 
stinctixely standing at the same relative distance from 
•>ach other, all trying' to swccj) e<iual spheres, and then 
buildiiitr up. or leavin^r wn^rnawed, the planes of inter- 
section between these spheres. It was re;tlly curious 
to note in ia>es of dithculty. as when two piece^ of 
comb met al an aiiL'lc. how often the bees would pull 
down and reliuild in ditferent ways the same cell, 
sometimes recurrin^^ to a shape which they had at first 

\V\wu bees have a place on which they can stand in 
tlioir proper positions for workintr. for in-tance. on a 
slip of wood, placed directly under the middle of a 
comb t'rowinir tiowriwards so tliat the comb has to K-e 
tiuilt over one face of the slip in this case the l)ees 
can lay the foundations of one wall of a new hex.i^vni, 
iu its strictly proper place, jirojectin^ bey(»nd the other 



completpd coll-^. Jt sufHics tint tho hees should Im» 
eii.iLioii ti) stanil ;it their piopfr rrlativf distAiici's from 
t'Hi h oth«T ami twin th(» u;ills <>t' tii.' l.i^t romph-ted 
cfllv., ar:d tlieu, \n .-trikititr ima^'iiiiirv sphtTtw. they 
t.i'i hiiil.i up a wail iiiteriiji-diatr ht'twet'ii tuo adjoin- 
ing' spheres ; l)iil. a.s far as J have seen, tliey never 
KiiaH away and tini>h oti the antrie- of a cell t.lla laru'e 
J. art hotli oJ that cell and of thi- adnuniiii: reil.s hn- 
• >••♦ ;i hiiilt. 'I"iii< capaeity in Kee- of hiyiniT down under 
.'.Ttaiii circum.staiices a routrh viall iii it-, proper plan- 
t.'tvM'eii two just-roiiunenced ceils, is important, as it 
hears on a fact, whii h seems at first (piite Miti\er-i\e of 
the lorciroiiiir tlieory ; namely, that tlie eells on the 
e-vtretne mar-in of wasi>-c-oinh> are sometimes --trirtlv 
hex.-iiTunal ; hnt I ha\e not s[).-iee here to enter on tlii's 
kuhieet. Nor does there M-em to me any treat ditfi- 
•lilty in a sin^h- inw,.,t (as in the case of a'ljueen-wasp) 
ni.ikin^ liexatronai cells, if >he work alternately on the 
iiisi<le and outside of two or three cells commenced at 
the name time, always st-mdiiiir at the jjroppr relative 
distance from the parts of the cells just heiruu, sweeji- 
!!i-'- spheres or cylinders, and huildinir up intermediate 
[•iiiifs. It IS even conceivaMe thai an insect mi^rht, 
M rixinjT on a poim at whuli to «-ommence a cell, and 
ti.. 11 movin*? outside, hrst to one point, and then to 
n>e otlier pointj^, at tiie j. roper nlalne distances fr-.m 
tiic cuutral p.,int and from each other, strike the 
J.1..IMM of intersection, and <o make an isolated 
.'ie.\;itfon : hut I am not aware that anv siicli ca^e has 
i>een ot.served ; nor would any t:o.i.l f»-\h.ri\ed from a 
■iiiit-ie liexaifon heiut.' huilt, as ni its construction more 
ninteriais would he retjuired than for a cylinder. 

As natural selection acts onlv hv the ac-umulatiou 
ot >^li;-'-ht modifications of structure or in«.iiuct, each 
jToiitahle to the imlividual utider it.s conditions .'.f life, 
t may reasonahly he asked, iiow a louu^ and trnidualed 
-uce.-Mon of moditi.'d architectural instinct-, all 
•eiiuintf towards the present jx-rfect plan of coiis'truc- 
iion, could have profited the proirenitorH of the hive- 
'"• ' 1 think the answer is not diflicult : it is knowu 






that UtM'> arc nfU'ii li.inl jin>s-tMl to m-t surfirient 
nectar; aii'l I ;ii.. jiifnrtiicil liy Mr. I circt iiit'it'r that it 
lia'^ Im'cii »'\iM'rimt'!i';illv tniirnl tint ii" L'--^ tli;iii trum 
Iwclvf til lillfcii |i(iiiki!n o} (li y arc < nn^uinf^l 'ly 
a lii\<' 111 Imt-^ fi.r liif scrrcin-i i.i iMth |i<iiiiiil nt wax : 
til tluit a |iriiili.'i()ii-; (|ua!iiitvoi tiiiid m<'tar mu-^t W 
ntlii'itrd ami ntM-iniicd l.y ilio I'ft's in a hivo tor lli(- 
-fcicti.'ii (•{ tin' nav iii'c('><ary Tor tlie coiistriK lion of 
tln'ir riiiiil'-. Mii;i'M\,'r, many Im'Cs liave tn rfm?iin idli' 
tnr iiKinv ii.iv> fiiiiiiiu' 'li'" ,'r<trcs8 of sn-rt Hon. A 
larL'*' store <it lionrv is !i;<ii>it'n-a'il(> to -iipjiort a lartT? 
-tock ol' ln'f- (lunri'.'' tin- \vi(il»T : ami tlie ^oruritv ot 
Ihi" !ii\t> i< l\']ov. II iiiaiiilv to dt'iM'f!.! on a laru'e luinihor 
lit hccs 1,1'iii^ >ii|.j)oit(d. Hciri' 'i;i' -avmu' "?" wav liy 
lar_'.'l\ •..!'. in;i lionr\ rimst In- a nn-t iinj'orlan; »'li'in<>nt 
of' ^:n ri'-.- in any tanul\- ot lit'cs. ( '1 courso tin' sun-fs-i 
ut any >j>»rii's ot Wtf may hi' dcjiondi"' on thi' nunilx-r 
ot its jiara^iU's or other rm'niU's, or oti quite di>tnu't 
rauM's, ami <o I'O altoL't-tlier imhmi'mlcnt ot" the 
ijiiantil}' of lio'ii'V w lii'h the lu'es could coilect. IJut 
let us sujipO'^e that tins latter circum-tanco detenu incd. 
a^ it jiroliahlv ottcn docs dctcrrnnic, tlie numhers ot a 
liunihic-l'ce which could exist in a country ; and let 
u^ I'urtiier s'i|»[,o-e tliat the coinnninity li\(>ii thri>u;rh- 
out tlic uiincr. and citn«e'|uently reijuired a store of 
hot;cv : there can in this ea-e he no dmiitt that it would 
he an adxantaire tn our hunihlc-hee, if a sli^'ht n'oditica- 
tion of ]ii r ni^tinct led )u'r to make her \vai<'n celU 
near to^jetlier, <o as to intersect a li!ile; foravsall in 
coiiunon even to two adioininir ceI!^, would sa\e some 
little wax. liciu'c it wiuild confiiniaily he more and 
more ail \ant.ijcous to our humhle-1'ee, if she were to 
make her cell- mo'-e;ind n, ire regular, ne.uer totretliiT, 
and a_-re-ated into a tu.i-s, like the cells of iho 
Meli]ioii.i ; h»r in this ca-e a lar^-^e pnrt of the houndinjf 
surface of each cell would -erve to iniund other cei'-, 
and much wax \Miuld he s;i\ ed. AiTam. from the samo 
cau>;e. it would ito ad\antai:cous to the Meiipoiia, if 
slie were to make her cells closer toLM'ther, and more 
reirular in e\ery way than at j>re-cnt ; for then, as we 



}iavp RtHn, tho splionral siirfares would wholly Hi»- 
;i|.j"'ar, «iirl would ,ill l>o rpj)la««*d hy |dniip •'urt'accs ; 
r'l.d tlip MtdijMiiia would niak*^ .t conili ;ts (uTtVrt ns tliat 
;,♦ tl.t" liivc-!n'o. i;»')iiiid th;> -t;i_'»' '>( jif>r!V(ti(>!i in 
ar<"hit<'< turt', iiriMirril srU'itidii cinild nut U'.ni ; fur the 
o'lili of tin* liiv»>-l)('c, fiH f'nr as we i rtii -ce, is aKsoluNdy 

(K-rfc-t ill OCdllnDii-lIiir \v;iN. 

'Ilius, as i h^lic. c, till' must woiidorful ut all known 
•-t'licts, tliat of tlio lii\ c-Imh'. can lio • rp'.ainrd hy 
I atiiral sclt'ctinii lia\inL'' tnkpu ad\;i!it,'ii:(» u* nuniprou^, 
«ucct<si\j., fihi^lit moflitira'ion> of -irnpU'r inntiiirts ; 
natural sclprtioii liav;ii:r hy >io« dj-iTccs, niore and 
irioro ji'Tifftly, led t)'p l.t'c- to sweep tMiual spluTos 
il a rivon distance from cacli ollipr in a douMe 
!i\f'r, ami to Imild u]f and t•\ca^at»' the wait along 
th'' jiiancs of int(Tsr<-ti(.n. I'ln' I'ocs, nt coiir-p, no 
ri'iirp kriowiii.T tliat tlioy swpjil tl;»'ir splicrcs at one 
i-a'-ticular di-tam-c from oacli otlter, tlian tlu'v kriuw 
uliat are tlie several aiitrlcs of tlic lioxajrona! [iri-nis 
and of tlio Ka>ial r)ionilii(! idatp-*. i'lic moti\<' puwcr of 
the process of natural solcctiuii liavinir hcen economy 
u* wax; that iii'liviilual nwjirrT' ulii'-li sa-tcd least 
honey in the secreiiun of wax. havinir suci-eeded he>t, 
H!i'i liaxinii tr.insiiiitted hy i'llK-ritiiiice its newly ac- 
(jiii'-cd econoniiral iiisliiirt to new swarm-;, wliich in 
til*' r turn will ha\e had the host cliance ot >ucce«<ling 
■n the struirt:!*' for exinteiu'e. 

No douht niaiiv irjstiiicts ot vc-ry difficult explanation 
c<'i:'d lie (>p]>(ise<i to the thcorv ol iiatur:'' ^election. — 
ca-c«, i:i w'h ch we caiiiiot sec liow an iMBtiiict could 
po-^hlv hive oriirir.ated ; cases, in which no interm"- 
diate trradatiotis are known to exist ; cases of instinct 
ut a]i]nre!itl\' such trin ri;; imj)ortanc<'. that they conid 
h.trdlv have hetii acted on hy natural seleclum ; case<< 
of instiiict.y almost identicallv the same in animals lo 

for their similarity hy inlieritance trum a co Timon 
parent, and must therefore helieve tiiat tlie\ have 
tn-eij ac(juired hy independent acts of natural sel-ctiou. 



I will not here enter on tJu'se >.»-\er.'\l <.i«t-, hiil will 
confine myself to on»» s|X'ii,il liiffirulty, whi« li .-it fust 
aj>j>car»'<i to mo in'ii|n'r;ililf\ ami .ittually fatal fn my 
wiioic tlii'ory. I alluilo !o the lu'iitcrs or -^torilr females 
in in'«ei't t;ommuinti«'> : for (li»'««e neuters often liitfer 
wiilely in inhtimt nnd in htrurtnre from Ixitli the niaics 
ant] t'crtile females, an<i yet, from livini: >«teriie, ihey 
ciinnul propatrate their kind. 

i he Hiilitoct well ilps««rves to he di>>ru»-e(i at irreal 
leiii/lh, but 1 will liere Uike only a Mni:ii' oavp. that 
of worknit: or slenio aiiLs. How the v*t>rkern ha\e 
V)oen reiiiiercMJ sterilt? in a difHculty ; imt not much 
ifreater tlian that of any other striking monifiration of 
HtriKtiire ; for it tan !>»■ ^liown that some in-»*<t^ and 
other articulate animals in a -state of n.'iture <»<'asion- 
ally hfiorne sterile ; and if such insects had heen 
social, and it liad l>efn profiUihle to tlie coiiirnunitf 
that a niiiiilter should ha\t' l»eon annually Imrn cajialde 
of work, hut incapahh^ of procreation, I can see no 
ver\ jrreat dilliciiltv in this heintr effected hy natural 
■.ele«-tiiin. llut I must jm^s over thi* preliminary diffi- 
<ult\. The trreat difficulty lieh in the working ants 
differini.'' widei\ fr'>in iioth the males and the fertile 
females ifi structure, as in the -iiape or the thorax and 
in Irfiiur destitute of winj^v ami sometimes of eyes, and 
ir» iiislim'. As far a,s in>-tinct almie is concerned, 
tlie prodnrious dirfercnce in Ihi- resjiect hetween the 
workers and the jtertVct ft-rnale-, would havf hcen far 
hetter exemiditicd l>y the hue-l>e«'. 1 f a Morkii!:f ant 
or otiier neuter insei't had been an animal m llie 
<ir<linary state. I sliouiii ha\e unhesitatiutr'y as'-^uined 
that ail its characters had been slovriv acquired (hroutrh 
natural selection ; namely, hy an individual haviujf 
been born with some slight profitable modiiicatiou of 
• tnicture, tlii- bciii:: inlier;te<i by its otf-pnng, which 
a^ain \aried and were at'^ain selected, and so oimardn. 
liul wiih tht! workintc ;int w** have an in>-ect differins; 
jfreativ from il.s parents, yet altsolutely sterile; so that 
it couid never hase transmitted successively acquired 
mtxiifications of structure or instinct to its progeny. 



jt may "fll ^e a.ikwl liow i^ it jimsmMo to reroticile 
tl in rase witli tlie t)i«>ury nf iintnral '<i»le«-tiori ' 

Kirxt, let it 1>« r«'riieinl>or(»d t) wo liave iririumer.iltle 
ins'.iiicorf, hufli in our .lntnostir jir<H|iicfi.<n-< aixl iti 
tlioso in a nt.if»« of nature, of all H<»rtx of riirf«»r»Mire« 
of" Htrurture wlii.ti hii\a hoconio (Mirrol.ited to certain 
.iL"'?», ^iiil to either «'x. Wo li,i\e ditfrrfnt-e** corre- 
iiifed not c»niy to one sex, loit to that short imtIikI 
al'Mse wlien the rejiriniuitiNe svsti^m is iutivo. us iti th«' 
iPMitiai pliiin:itrt» of manv lirds, arnl in tlio ho<ike<l 
ta".*s of the mile salmon. We have even slu^ht Hitfer- 
ei'.cos ill tlin horns of different l>reed«» of cattle in 
roiatif)!! to Hii .-irtificiallv imperfect state of tJie tiifiln 
•^•\ , tiir oxen of certain Kreeils lia\e loiirer !ior:m than 
Hi other breed-, in conijiarison with the lurns nf tjio 
hulls or co\v« of the>« H.iriie hreed-i. Heiito I can 
•^ee no real diDiciilty in any character liavinjr liecnme 
correlated witli the sterile comlition of ce- uiin tiiem- 
hen< of I'lsect- communiticH : the oifficuitv li"s in 
iHiderstandinir liow «uch rorrelatoil rnodi'icatiniiH of 
structure could have >>een slowly acrumulafcd hy 
natural -election. 

This difficulty, though apjiearin^f insuperahle, in 
lessened, or, as I believe, (li>apj>«varM. wlien it is r»^ 
!nembered that selfM'tion may be appl'"d to the family, 
as well art to the individiial. and may thus irain the 
desired end. nius, a well - liavoured vei:etaMe is 
cooked, and the individual is destroyed; but the 
horticulturist oows needs of the same stock, and 
co'itidontlv expects to eret nearly the .same variety: 
breeders of cattle wish the I'.esh and fat to l)e well 
marbU'd to^retlier ; the animal lias l>eon slauL'hterefl, 
but the lireeder foes with confidence to the >ame 
familv. I have such faitfi in the [lOwers of -elert^on, 
t> 1 do not doubt that a breed of cattle, alwiys 
yieldiiitr oxen with extraordinarily lontr horns, could 
be -ilowlv formed bv carefulh' watchitnr which indi- 
vidual liulls and rows, when matched, prr>duct»<l oxon 
•*:''; the loniri'-t horn- ; and yet no one ox couid ever 
iia^e propagated its kind. Hius 1 believe it ba-* been 



Willi BOiiil iii-rcL-H . .1 -ii^'l.t (riOiIiIn-.-ition of stniclure, 
or iiiHlinri, riinelitol with th«? >t<'ril« niriditifm of 
Cfrt.iih ii.«.-ifil)t'rH of" tJi« cnrniniiiiitv, hi<i hfcri aiL.iii- 
tau«'"His to llii' conunuiiily ; i diim-ijih ntly tfi«« M-rt 1»» 
ma!««- ,V"I iViiialos of tii«' same rtiiMriniuitj ti<iiir:-li«»«l 
•ti<i iiaii>roilt»-,| to tli»!ir ferl;l« oi^(»riiiL' a ti'ii(i««iii'v t<. 
protiiice >t<*ril«' tinMiiliiTs liavinj; the -Ninue tiinduici. .nn. 
AipI I t.rlif'.i' th.iL liii- pr(ii'f«'4 li.n '.fcu r«'|.»-.itc.l , 
Uiilil III. it |>riil;t.'ioii>i ;iiiiouul <il ililh-Kvi. « ln-lwreii the 
fcrlilo .iinl iiTih' t'eriiulo of the -iiim' -[lericM han heeii 
|»n>iiiii I'll, \*l,ii'h w« M'c ill rii.iny "ncial iiiscctx. 

Milt we h:'.. »' imt a^ yet toijclipil uii lh<" < liniax of tlic 
(lillifii;\ ; :. Ill .■|\. tiu! I'.n-l iliat thi? nouters of se\er:il 
&iit'. liniiT, I it iiiiiv trom iIk- k-rtilt* f'fru.ilfi .iinl 
rnalt'-, Imt iroin carli oilier, sotiieUiiie-< to an 
im:r»!(lilile U»'4!;rfe, .iii.l ,ii»- tluis divuied into or 
even flirei' '■.i-lc-». 1 lio ia»t(»-, inrirfovi-r, do nut 
Ifeneraily tfr.idiiate into »'aih tittier, l«;it are jierfVitly 
well defined ; hei.ii: ;i-* distinct ircun e.ti-h oflier. .ts are 
any tvvo spet.e-. of :lie same tieiui-, (»r ratlirr as any 
two i:<-nera oi the -^anio family. Thus in Keiton, there 
are wuikintr ■irid -oldier neuters, with javvs and in>.linct« 
extraoruinaniv ditferent : in ( ry|i!ooeriis, the workers 
of oi;e taste alone earry a wonderful sort of -hield on 
th»:r heads, the ii-,e of w hirii is ijiiite iinlvnown : m 
the Mexican Myrineeueystus, the workern of one caste 
uever leave the ii»'st ; they are fe<l hy tlie workers oi 
another c.-isie, and tncy have an enormoi: Iv de\tdoped 
alitluiiien >vliich accretes a sort of honew siipjdv.njr the 
place of that e\» reted liv tlie aphidei., or the dcmiesli ' 
cattli' as thi'v mav he cHlled, vftiich our Kuropeau &ntM 
Ifuard or iinprisdu. 

li v.ill indeed he Ihousrht that i have an overweernntf 
confiiience in the principle of natural selei-tion, whfu I 
do not admit that sucii wonderful and well estahli-hed 
(act^ at once annihilate my theory. In the simpler 
case of neuter in-ecLs all of one caste or of the .same 
kind, whicii ha\e iaien rendered by natural selection, 
as I l)«'!ie\e to he (juite pos.sihle, different from the 
fertile males and females,— in this case. v*« may safely 

t - 




. >i.rlii(le from tlio .iiialui:y of onliii.iry v!iri.itit»ii>», thnt 
.• .<li nui:t«'->-n»', ^licht, pruht.iltit' riKMlii'n .itioti iltii not 
[.rdlijililv III tirst apiiiMr in all tin* imin itlnal • • r.ti-rx in 
;in« saiUf in'-t, I'lit III a It-w alniic ; aiiu tliat tiy the 
!i iii;-ruiif;iiij''<l M'leifioii of tlie* [Mtcnt.- »liicli 
Mro'lii-t'd niixt iifutiT"* v.ilii tlu! |>m t';;.i!.tf iiioii.tii a!:<'ti, 
il' tilt' hcutrri liitiMiatfly (Minf to lia^f tin- (le"*ire«l 
aractfr. < 'ii tin-, virw we nii;:ht o( ra.-iniially to titid 
;.fiit»'r-ins»>ft.- ot tin' -a'lif Sjifiii's, in tin' vaiiin iir-t. 
I>i ('-I'iitiiiir crailatmn-. nt »triictiirt* : ainl tlii-* «•• >lo iin<l, 
.■••I ollt-n, roiisiiliTiiiLr liu.v low in iitfrii.-«'i 1 ^ nut of 
i'.iirojie hnvr hcni carffuiiy »'3kaimiirti. Mr. I'. >iiiitli 
h.i!* Miov*n Imw surprisinL'ly tin* nrutfr-. ot -fxrral 
r.iiii>h ant-i itilftT from tarh nthtr m -./.f ami »iiim'- 
tiuics in rolour ; and di .1 'he »'xtriMti«' form- tan 
M'metirnes li»' |i«'rf»-i-lly linked toj^'cilirr hy imiis idnaln 
t.i' »Mi out of thf sam« in>l : I liavi- riiy>t'lf •■omj.tri'd 
;■. rfoct irradatioiis of this kin<i. It ottt-n happen-* that 
till" lander or tho «-malli'r -.i/a'd workers .are tiie most 
•inmerous; «ir that holh larsje and >mall are numerous, 
Mih those of an iiiternie<iia'e si/.e scanty in iiumhers. 
bormic-a fla\a iias larjfer and •.mailer worker-., vvith 
soiTie of inlt-riiiediate f\/.f ; ami, in thi-i «pecies, as 
y,. V. >niii.i. h;i.s oi)sfr\e<l, liio lar;^er workers ha\e 
..)!nple eyes (ocelli), which tli<uii.'h sm.iil can lie pl.onlv 
1 -t;n^'!i>Iied, wher«-as the -mailer v\orker> ha\e their 
iicelli rudinn-ntary. ilavint; carefully di-.--ected several 
-pecimeu- of the-e workers, I can aflirm that the e\es 
a e far more ruiiimentary in the smaller wnrker-. tiiaii 
I II he accounted tor merely I'V tlieir pn.poriionally 
le'-er si/.e ; and 1 fully (ielie\e. though 1 dare not 
a--ert so |Misitively, that the workers of intermciliale 
-i/e have their ocelli in an exactly intermediate con- 
d ' ion. K > that wf here hav^ two hodie- ot sterile 
workers in the ><ime nest, dilf'erin;: not only in si/e, 
hilt in their organs of vision, yet comiei-ted hy somt 
tew memhers m an intermediate condition. I may 
(l._'re.-s l)y addiiiir, that if tiie .-smaller worker- had oeen 
the most useful to the community, and thoM- males and 
fe'iiaies hao ite.-i enrit i'.;ialljr selected, which produced 




more mirl rmiri' ni 'lie ^iiiillfr ivorker^, iintii ail the 
workers lia.i <()riH! to lie in tlii-^ cdiii ;ion; >v(' slioiild 
then \i:i\i' li;nl a -[mtm's of ant witli !:(Mif«>rs \«tv iioarlv 
ill \\\f -ainr rni,(i:MMii tlio-c (tf M '.rniii'a. I or fln» 
worker-- ot M} iiiin' t haiC lint owu ruil'Tr.ciU.'J of ocelli, 
tlion!.''ti the Tiiali' and teiiiali- ants or tiu> C't'ij-i lia\e 
wt'll-rlevelniici] 0( el li. 

I inav iiiNc one other ca-^e . >-o coiitideiitl v did J 
evjM'et to fiiul u--aiiati(Ui-. ill iiiijiortaiit points of strtic- 
tu" '!v\eeM the dirieieiit ca^'e- of m-'iters in thn !*aine 
>»•'-.• that I i:l.iiily ii'w'iiled nivselt o: \]v. K. >miih's 
• • '• - of TiMtiieroii-' >tM>ei;ner.»; froiti f!ie -arne rie-f of the 
im; i\"a. ' AMuitinii I (It V est Atriia. I lie reador will 
JM I li.-.p", til -I ai'ji-eciHle tiie arnoi;!it of d'^ftTencp in 
' lic'C woi'ker-i. t,y iiiv iri\intr ii>'t the aetual iiiea^urp- 
!iieiit<, hilt a st rut 1\- accurate illustration: t'le .iit»,>r- 
fiee was t!ie ^aiiie .•»•» if we w«'r(> to sec u m' of worKfiien 
loiildih;/ a ho';-t« (if whom nianv >vrre tivf feel tour 
imdies luirh, :<nd nianx' -iivtee;! leet hiL'^h ; hut we iinist 
supiiose that the lar^'er workmen hid h<-ads tour iii 
stead 111 three line- as hi^j- as those of the smaller men, 
and ia\*s nearly live times as ii;!,'. The jaw-;, mnrp 
<ner. >i: t lie '.vork iiiL' ants of the several fiitfere<i 
womlerMi ' ! V m >-h ipe, ai.i! m t(:e furin and Tiuniher of 
the teetii. IJut the important tiict tor i;s is, tliat 
thouLdi the workers ran he trrouped into rastes of 
diih-reiit si-es, yet ti'i\- trradiiati- insensihlv ipto each 
other, ris does the \Mdelv-<lirterent structure n* 'lieir 
JHWs. ! speak contideni'v on this latter jioint, as 
Mr. lj!''Ko(k made d'aviinirs tor ri.e nith the camera 
luiida oi' the iaus ,\|.iih I had dissected troiu the 
\\orker- of the --eM'rai -;/es. 

\\ ith the-e 'aits i cfore nm, j he'lext* that natural 
selection, i'l. acting oi; the fertile par. "its. could form a 
species whiidi should reirulariy produce neiiters, either 
all of l.irj'o si/e ■Aith one lorni of' -ia. or a!l ot^ s;n all 
si/e W'th laAs |;a. !!;;.: i w i<!el\- different s||-ii<'ture; or 
iasip, , an*; wirs i^ (*"ir x'i'iiiav or tiorn'uii\', wiit* sd <»r 
worl ers of one si/e and »'ruoture, and sinniltaneouslv 
another set <d workers of a tiilfereiil size ami structure; 




a ^r.iflua''><' "prios havintr t>f»Mi tir-t tormt'ii. a.- in tho 
case of t}ie drivpr atit, and tlieii \)iv extn"ii»» forms, 
tmm iM'iii^r ♦i'*' n>'>"^t useful to tin' roinnmiiity, haviiij 
tjoe.'i,ir»'<i 11 irrc-itcr and trreator riiir!ii.t'r> thrrMiirli 
tilt' iiatiir-i! -ii'ii't iiiu! of the j.Hrt'nt-; wliuh {.■■»-iif..itoii 
•'';cm : until ijorie with an intoniu'diate stnictuiv wcf 

'11. iH, a-i I i'plif'vt^, tli«> vvorid.Ttul f.'iot o; two <i;'- 

tUH-tlv (h'tint'ii iastt'< of stt'rih' wnrkcrs existiiisr in t.-H' 

"aine 'ne-t. Imtli uiHciv liiitprcnt f'rotM t'acli I'lhcr aiitl 

from tlitMr jiarcnt.-, ha-* ('riiriiiat*"!. W f t;'.:i 't'O • "^^_ 

li-ffiil lli^'ir |»r(M!ii"-tioii n.av lia-.o '<<ri-'.\ lo a -' c:.!. 

••«iirin,-ir,!!y nf i';vt>ct>, on •he -an>t> pr: n'Mf>it' tha' t!"- 

.'ivi-ina of lal»":r 1-= usetMl ta tiiau. As •i:.t> 

w.>'k iiy inhcnttMl iiistinrts an«l !'y mluTitcd ori'-ans or 

incU. ami iK't !iv aojuiroil kiiowlcd;:*" and nianurac 

'.I, red instruiiH'i.i- :\ ;'i'rN>'-* d'.vi-inn of la'.tiur fouhi 

lu- .'trecf.'d with tht-m oulv liv tlii' vorkors lieiiit; 

-tfriie; rrr had thev ln'cn fertile, tliey ■^<nl\<\ !ia\( 

.iiterrro>>i<-d, ami tlieir iiis'Jiicts and ««trin'ture womK' 

have he.nine tdended And uatnre has. .i- I I'elieve. 

etfet'ted tln-i admirable division of lal^our m trie (M.rn- 

ripin'tie- of ant-., hv the means of ^election. 

Ku* I am !M.und to 'eoiifess, Miat, with all rnv faith n 

th;- [«rHn-ii''e, 1 nhonld never ha\e antirj'ated thai 

natura' -eleitioii could have heen etfinenl \n H" h't-"}! 

a eiiree, had not the ca<e of these neuter iiiseet^ 

oniir'.iued ine of fie faet. I h;i\e. therefore. di>.-u-;-e' 

tln-i rase, at some i.ttle liut wholly in-utfiiient .enifth 

I'l oriitr fo ^how the power of natural ^election, ami 

likewise heeause this is hy far the most s»tumis spei'in' 

d-i.icultv, v\ mv lhe<iry has enc<iuiitere(i. I he 

i'.'i»e, also, is verv interesting, as it proves that wit't 

animal-i, as with plants, any amount or ni.idifnatio'. 

in structure ran he eilf-'-teii ItV the a. euniuiation of 

numeruMs, -.I;_'ht, and a.- we mu^t ea!l them aceidei.tal 

variations, wliicli are ni anv manner proii'.ahle, uitti 

iM.i e.\eni>e or ii.ioii iiaViiitr vOnie iii.i; }•:•'.<■ • *•'■ •• 

aiiMiiiit of e.\erei-e. or halnt. or volition, in the utterh 

rue members of a ooiiiMiunitv i-ou 



dv ati 




the Ktru.'tiirc (ir iii-ti^ict.'* of tlio fV-rtilc menihors, which 
aioiir 'i-;ivi' (it'-^( fill! ants. I am Mirpri^pii that no one 
has aii . iiu'ed tliis (icrncustrativo ( i>f- of H.-utcr iuseit.-, 
aj.:a]ii>-l Iho woli kiii>,\!i (iortriii' ot i.aiiiarrk. 

^■'////'/<•,■r7. I lia\(' t'h'i('a\ (iiireil I'i;i't1v m tliis c!iafitf>r 
to -how iliat the nu'iital (jualitiiw ot our tiniiu'»tif 
aiiiiiiils vary, aim thai the variations ar«' inlierit»'fL 
Still in<ir<' hriclly I have atti'nijitcfl to show that 
in«-ti!nt- v.'iry sli^^litly in a «tatc of nnt'ire. No one 
will (ii-piite that iiisiincis arc- of tin." hi^iK">t iin(,ort- 
aiii-e to caih animal. 1 iien'forH I can >»'e rin lilhiulty. 
iiruier fhaiiLnnj.' conditions of lifo, in natiiial selection 
a<-( ii'tii;lafinir -litlit niodirii-ations of instinct to aii\ 
extci.i :n any usetul direi lion. In some ca.-ie>- i.alnt 
or 11 f anil (Ji-n-c have {)roh:i!'ly con.e into jil:;v. I 
dii not |;;-olend that the "act.^ y-i\en in this ch.tpter 
Ktrcn;.n!o.n in any tcreat ueL"<'e my thoorv ; hut none 
oJ t!io case> of d'llii'ulty, to the host of my jiidL'ment, 
aninhiiasi- it. On the otner liand, the fact that in- 
stincts .ire ml a] way- ahvdutely perfect and an* liahle 
to ni:.-takc'; :- that no iu>linct h.i^ I'cen pf iced for 
the cvclu ive good of oilier animals, hut liiat each 
ai inial takes achaiita^e <if the in-lincts of others ; 
- tiiit the canon in natural hi>''iry, of 'Natnra non 
facil saltiiiii, is applical.le to instincts as weil as t<i 
eoriHireal structure, and is plainly cxplicalde on the 
foreiroing views, hul is f>therwise ii.evplic:ii»le, :i!i 
tend to i-orrohorate the theory of iralural -clectiua. 

I ills thcorv Is, also, strcntrthened hy .-ome few other 
fact.- :u reijaM tn ;n-;tiii''ts ; as hy that common case or 
clo>ely aliieil, hut certainly distinit, spei'ies, -.vhen in- 
fiahitii.:: di-tant ji.irU) of the world and liviny under 
ci'iisideraidy dit'^Tent conditions of life, vet often re- 
l-unin'r nearly the same instincts. For in-tance, we can 
undcr-tand on the principle of inheritance, how it is that 
the till ii-h of .'^oiith America lines its nest with mud, in 
till* .-.iiiif [•••ruiiiir manner as uo«'s our t>riti-ii ihrusii : 
how It I.- that the i ale wrens (I'mtrlodytes) of North 
America, hiiild ' coek-iiesU*,' to roost in, like tlie inalas 




f iiur (lUtinct Kitty-wrens. -a hahit whi.;ly iiriHkf tliat 
)f :iiiv otliL'r known !iir(i. Finally, it may not lit' a lni:it-al 
U liuclion, liut to my imairmation il is* tar niort' <ati,-;a<'- 
'..■ry to look at <i.cli in>tini-t-i a^ the ynunir curivoo eject- 
!j-- it** tn'.tiT-lirMi.hfr-. — ant-i making '•lav»'«, - lin' lar\«> 
>t iclnHMiinouitli*' U'criuiir within the iive hodio ofcater- 
iillars,--not as specially endowed or crfaU'd instinrts, 

■It a- -,],:ill <-rin-M"ijiieni'es of one ireneral law, loading 
•-o tiip advaiit fiin'iit ot ail orj^anic hoinir«, nai..r!y. 
-> ult:[)iy, varv lel the htrouffest live aiui the weakfst 


< ii A 1' J !;i{ \ni 



(tJi!!"'-*'- I '-!vr.,i,i the ft.rili' f llrst r.-"< v.^ .f '.v-U- 

ve.I l.y il-.. , .,1-1 aw, ,' ,ity 

^i '■■ r.rility n ,t a spfcial >-ri'..\u,rtii, i.ut inii.ittnUil 

t^n '' :i -IS' -rmises if th'- st.rjtx <■! (Irit onis-se* kn<l 

of hyr:;- farull.-lism \>i->.wfei; th- .■(T.-rtii ..f r-hanRp.! con- 
dltl-ns ..f life n,„i . p.isii,!.. K-rUlity . f vari.tie* wlu-n rr..sse.J 
•ml ..I tliiir ii:..ii-r<-l rr-prl'iK ti-t iinivenwl Uyt.riils ami 
n.ougrel* ••.niparc ! ii:.iej»-i, irntly ..f their fertility-Suuiniary 

Ihk vifw u't'lit'rally eiitcrrairu"! ''v iiatiir,il;>t^ n fiiat 
"l^ccic-.. wln'M nitcriTo-M';, li:i\i» licci <jK'<-i;i:ly cndo'M'd 
wuh the tju.ility of stmlity, ti urdtr to [ircvrnt. tlipcitri- 
fiisioii of" 111 ..ii:.i!iic forms. Tliis view ct'rL-iiiily ^eeids 
.it fir>;t [•robaliic. for s|i(Mios vviti;i;i tlic same fouiitrv 
■tmlii l;!rili\ have kept tii>r!iicl ha<i thev heei, . apaMe 
of crossinL' tret-lv. Tlie iiiiportanre of the fun that 
h\i.ri(l«< are verv iretierallv sterile, ha-, I iliink. Keen 


miii'h umler.'-ate'l hy some late writers. On itif l! 
')' iiu!nr(ii ■>'-i,,tii>n thr C'/.v^ r.v fsfn'nriiii ivij>i>rtiiut . uinv- 
rnnvh <I1 fh*- stfrjitf^j iif' hi/'.ri'lji t-DUid not piisslKly Kp of 
nriu (t(h^:>itiiijp to (hrm. nwi tlwrt-torp muni uot fun^ 

^>frri t!(-<jHlrr,l f,ij tfif <;nttinni'/l J)ris>Ti::;\,,i, nt' SIKTfX- 

xirt' profit'if,.!' '!iu^feg of' xtfriiutj ! hope, liowpver, to 
be ahie to .sh"^v that sterility i- not n -j.e.;.i:'v ar.juire(l 
oreii(lo«e<i .|Li,iIit\-. toit is i'!<-idem;il ou other a.'.|4irei) 
■ iii'frences. 

ill -rea; itii: tiii-^ siiii,eit, two ri.i>.>cs ,,> tuts, to a l.iri^e 
p\'rrit iiunlaiiieiitaliy (iiffereiit, ha\e L'-i'iien.llv been ori- 
foiMi.le.i toir,.tl,er ; iiameiv. \\ic sterility of two sju'eien 



when cro8»e<i, and the sterility of the hytjrKi--* pro 
■l.K fil trom tiiem. 

I'lire *j>eri»'s have of course their orirnrii^ oi r('[iri>(tui- 
LJoii ill .'i jterft'it rniniiliuii, ypt when uiterc r()>se'l l'ie\ 
iirudijce eitiier \\;<^ or no otf^princ. llyliriii-. ti'i the 
ittier haiui, have their re|ir<xlu( tive or^r-ins funciiDnaliv 
liiipdlent, as ii.ay lie cU'arly seen in the state ot the 
male element in l»uili [>l.iut>t and animal.-. ; tiinutrl' the 
ortraiio theniM'lve.x are perfect m struilure, as lar as the 
!iurrosc<ij)€ r*'.''als. In the firHt case the two ^exiial 
"lementh wiiKii (/o to torm the ernhryo are perfect ; in 
;lie second cjise tiiev are either not at .lil 'lf\ei<tiH'd. ur 
are imperfectly deveh)peil. 1 ins distinclinn i.« imporUmt, 
wtieii thecaii^e of tlie sterility, which is coinmon \n tlie 
t«<i cases, hat* to !>«» cii!i-<iderisl. I he di^iiiiction iia- 
lir()i>at)i\ heen sliirr<-<i ovrr, owin^ to the sterility in 
..ii'li cases heiiiic loi)ki-<l mi av a npecial eiidnnment, 
liesnnd ilie priivince m our rea-'oniuir pov^cr^. 

i lie fertility of varieties, that is t»t the torm.. kno^vl, 
uT believed to have descended trom coriitnr)n p.irenin. 
wi.en niterero^sed, and like<*i»e tiie ferluity of their 
;nonL;rel ()f'"sprin^, is, on iiiv theory, of e<)i-ial iiiiport- with the sterility of species ; for it -eem- m make 
a iiroad an<l clear distinction l>etween varieties ano 

".pC. iCS. 

lirst, for tlie sterility of species when c^o^M■l! aii<i or 
lI.c r hyltrid offsjirinir- It is inipossitdt' to m'ii1\ the 
-eseral iiicmoirs and works of tliose two con-^cientioiis 
and adriiirahle oi)servers, Kulreuter and <f.irtner, vvho 
aimosi devoted their lives to thin suhject, wiihctut tteiiiii 
(l»'»'piy impressed with the hijrh trenertiity of some .Ifirrfe 
oi -lerility. Ki Ireuter makes the rule univcr'-al : i.ul 
the;, he cuts tlie knot, for in ten c^i-e^ in which ht 
found two forms, considered ity most authors x- distinct 
spe'ie**, quite fertile together, he unhc^itiititii.'-ly ranks 
them as varieties. G.'rtner, al»o, makes the rule 
e.iu.iliv universal ; and he dispute* the entire tertilitv 
of K 'ireuter s ten cases. But in these and in many 
other cases, (iartner ib ohlieed carefully to count the 
•ie«ii,, ill order to show tliat there is any detfree of 



wteril'tv. Ht' always ronijirircs thf nirixiiinini ii'irnh'-r 
of >-P( 'i-* yirndiicci] Ity 'w.. ^jifvie- wIumi <T(is«cf| mid hy 
tliPir ]ivl»ri(! nfV-prin;.'-, witli tli« averai^o iiiiin!i»*r pro- 
(liKTil l»y liotli jitirc jiaront-sporira in a stiite ot iia'.ure. 
Iiiit a K»*ri(»ii;i cauH* (iT <Tri>r =f<'iiis to mo U) }<o ]i»'re 
introfii!«»«(l : a |»laiit to n*' Iiy'»ri<iiM'(l t;iii<1 In* castra^p*!, 
aTiii, wliat is oltrii nmrt' in.itortant. niii^it l>e ^«'r!ii(l»»d 
ill DriltT to |!rM\ cut jidllfri 'ifMntr liroiitrlit to it !iv n^»'rt« 
!r(jin othor |il:iiit.'i. Nearly all tlic plants ox|»<»rimpiit- 
iscd on l>v (iirtiior wore pottod, aii'i apparentjv \<f>re 
kopt iti a <'liaTnl'»>r in liis hou'^o 'f"!:at ili'^«<» prf»<"f<sp« 
;ir<> nfU'i; in ■'] riuw 'o tdo O-rtilitv of' a ii'ant (•a!:not 
'■I' <iuiriit<'ii; for 'i'TtinT l;:'. ("J in li'- s.uii' .■i'>i'-ir a 
-core <;♦" ca^ f> of plants wlm-ii lif ca^lratoil. and rtr-tili- 
■•iaM\ fpr1ili-''d «itli tlipir o^vm poi!i"i. ami («'x<'liidintr 
-i'l ("ISPS r-uili as tli'» l/pcruniinosa', in ulijch tl.prp is au 
irkno\v]'"^::pd ditri-'ull v in tin' Tnanipula'ion) li.alf of 
' Vii st> tiN'Piitv plarit- lia»i \\<<'\r ffrti!;t\- in some (Ipjtcp 
unpaired. Morco. cr. as ( J ,r»nt'r iJurir^iT Bc^t'ral vpars 
rpppatcdl\' ij"os>t'd tlip priinrosf* a;id (ri\v>!i[), whicli 
wp ha\o sindi o-fKul reason to i^clMnp to t'P \aript'»'s. 


oi:]'.' 'iin'c ur ♦"Aii'p >Ji|.v"Pi'ii('i! in irPtlinLT fprtilp 
sfi'd ; a.^ ho found tiic roniTMon red •;;i(| iijiip piin- 

pf'iicl-; (AiiaL'';iilis arxcnsis and 
l'»'-t Uo{ani-t-< rank 


as \arii'tips, a'lsolutt'lv -UTf:*- to 

iTP'lipr ; aTid a"- in- caiiu' to tlip Kame coii.'li -loi in 
sovcral otliei' .maloiro'is t*ris.>s ; it stH'm- to riir tliat 
wp u\uy M 'II hp pcrinittfi! to doulit wiictlior many 
"tliPr --jP.'icv are rrall'. "o stprilp. wnen inter. rnssed, 
■IH ( i.irt IMT 'ndio,'. es. 

It. 1- pertain, oji tlip onp hand, tliat *}ip sterility of 
\ anions spp<'ii'«i when prossed is po {!!''^rreet in (ie>.-r<'t* 
aiid frradnatps a'-v-»v so insensildv, nnd . nu tlie otjipr 
hand, that tlip fer'ilit}' of piirp sjiecips \^ -ii easily 
a'ipetpd !)y '. ari(»ns pireunistancps, that tor all f>rartiral 
purposes it is inn>t ditlieult to say w'lprp [iprtect fer- 
tility en.ds and stPrility hetriiis. I ihnik no lietter 
• '\ !,|pn<"»' oi thix c-an he rp<juirpd than tliat tlio two most 
•'\p"r;>Mie('fl ohsprvprx who havp c\«'r livpd, namely. 
Kolreiiter and tiartnpr. slionld have arri'. p<i at <lia- 



. 1 

•notrii'nllv ojtj>f>«it»> r<)7ii'lu-<i(>Ti> iit ri'mni to the very 
-.".;.♦' sjtfc'.p. It ;s :il-«t ino.>.t iii^lnn'tive »<• • > i> — 

|i\t I li.ivp in>t sjiice )icrp to piittT oiMir'ii "vj- 

dfic*' adv.iiMM'd l.y our l/cst l)olai:isU o' "u 

wliftlicr rcrtain (iduhtful f<irni«« kIioiiIcI iiv r.r.i>^>->'. ,(s 
<j>t*<'i»"< or varif'lips, wi:li tlie evidonre tVimi Jt-rtility 
■i(i«luc-e'l }iv di'l'Toiit hyWridiscrs. f>r hy tlif» .iih» anitior, 
T'l fxin'rinxMi's nia«i<' d^rinir <iifTer«Mit ytar)». It can 
1^ l)0 ^!lll'AIl that !i»MtliPr sterility nor fertility atftml.H 
1 i\ ill ' (li-liiMlioij l»elHoe!i spenos aiul ^ irieties ; but 
( it tht' oviiiniic from tiii-; ^ourcp i.'Ta(lii:it«'> away, and 
i- (iou'ttnl ill fhtxHuu' <lf'u''rpp as \n tlu» evidoiire derived 
■rii;ii (it'cr cnn-titiitinnal and stnuinral riilifnTices. 

Ill r.'uir'i to iIh' stiTilitv of hyliritjs in >--iicif's-;ive 
■j.iH'ratioii^ ; tlinu^rh (J irliicr wa« piialilod to rear <ome 
)i\ iirids, I'arct'iily trtiardiiitr tlicrii from a rross with 
.I'htT jturc {i.iront. for -'\ or «(>vtMi, and in one casp ror 
■f t;o!if>r:i!iiii>, yt't be :i-t'rts jio-^itively tliat their fcr- 

• I'tv never iinTciseii, hut trtMi'-rally trr-'ally i:(>(rea-;Oii. 
I (lo not lii.ui't lliat ihis iy usuaUy the ea-p. and that 
•hi' terfilitv oi'ten ■.uiiiiflily decr.a-e-. in tho fir<t fo'"^ 

[ ciifraMoiis. Nevertlielos-; I Ix'iieve th it in nil tlievo 
er[vf'rii!ients tlic fertility has lieen iliniiiii-hed !^y an 
ii:(leTieniie;it caii-ie, namely, fr< 'ii e!n-e :;if er'ireed'iiir. 
I l:av(« eolicited so lar::*' a hody ot tact-, shownii.'- 
•1 it olo-c iiiterlireediiiL' lps-en« tortilitv, and, on the 

■tiier liaiid. thai aii (u-<-asiot!al cross wivh a di-tiiict in- 
cjivid'-al or variety mrrca-^es fortility, t!;at ! caMiol douht 

h" eorrprtiu'-^ oi 'liis ahiei-t iini\<T-al heKel amonu''Ht 
l.f.ders. li. toid-; aro ^(.'ldonl r:'.i-»'d hy experiim-n- 

• ili>f.s 111 en'at ii'itiihpr» ; and a>- the parpiit-sppeies, or 
.♦tier allied livhrid^. L'eierally ;:row ii. the sariH> trarden, 

the visil> of insert- niu-t he careluliv prexented during 
tpo floweriniT sr-nson : henre hyhriils uill ironeraliy U> 
i! -tilised diiiinir eaidi treiieration hy their own indi- 
vi.liial jiollt'H ; and I ani eonviiu'ed that l)ii- would ho 
in 'irioui to their fertility, alrerniy le«.-erii'd *■; tl eir 
iivttriii or'^rin. i am s!retiu'Uii'"<''i '" ''■■' «."inituou 
Iiv a riMiiar»watiIe statement re]>ea;e<i!y niad»» l»y 
(iartner, namely, if even the le^ss tertile hyhrids 




li<« .'irtiiiiMiIlv fcrtili-o'l with !:\l)ri(I |MMlfii of tlie same 
kind, their trrl.i.ty, imlvvil ti- t.iiuuiii: tin* fn-ijuput ill 
elte( t> ol tn.iiiijiiiiatioii. soTiiiM !iii»'> tU'cHUMliy«'S, 
arid <;ot's on iii'T('.i«i[ii: Nnw, m .iriM.i IiTlihsjiiiuii 
((iiUfii is a-« iiPt'ii taken hy ciiance la- I know from my 

■ ex[tenenrf) Irnrn the aijiher> ol aiii»rlitT liower, as* 
i.iim ti,,> antlier.-' ot tiie linger it-oif wliiidi is to he 
lertiii-i'd ; so that a rro^^ iietwi-en t^o iloner-, thoiii:h 
prtduid . oil the Name phinf, would lie thu- Htieitt'd. 
Moreiiver, whi'i.fViT (<i.'n))licated evperitufnts are m 
proure"!-*, so iMretiil an ul-server an ii iitner would h ive 
M>traled iiis h_\ i>rid-, aii'l thi^ would iiave uisuixmI in 
earli trfiif'ralioii a«rossHiih a poih'ii from a di.-t'iict 
fuwer, eitticr iroiii liie same jdant or Irom another plant 
u tiie K.i!iie ir, hnii nature. And ihu-^, the >' raiii^e Jailot 
the Hicre^'i^e of fertil.ty in the sin ce-sive jreiieralions ot 
iirtijuiiii/y i>-rtuistii hyhrid- riiav, I heiieve, he accoiinted 
tor h\- clioe interhreedm^ .ia\:nij heeii avoided. 

Nir.s let us ti;r;i to the r«'-iiils arrived at hy the third 
nio-i ev|itrienci'd h\'liridi-«'r, naiiieh', the Hon. and 
Uov. \\ . lieriiiTt. i ic 1^ as e!n|i!:atic III Ins fonidusion 
liiat some livi)rids are perfect!) Jcrtiie a-s fertile as the 
,in;-e parent -^pO'■ie■- a- are Ivdreuter ami (.i.irliier 

■ .lat >uine (iejree ot sterii.tx lie;.\een sp»>cies is 
4 iiii:\er>ai ia"A o!' nature, lie eiiicrinitaiived on >oiiio 
ot tlie \er\ same ^pe. ie^ a.-- did d.irtner. I'he d.iter- 
enee in tiieir re-iill'- rt.ay. 1 tlnnk, he in part acrounu-d 
for i»\ iierherts trreat fior' u ul; ural -kiii. aiid hy ins 
ha\ inir hotii(iu>es at hi- iMiiiiinand. * 't iii> maiiv iiii- 
]ii>Mant staU-fuents I will here irno only a sii:.:le one as 
a'i exaniph', namely, tint ••e\ery o. nh- iii a pud of 
<. rniurn i-..'i(:i^e fertili--ed l'\' ( . reNoI'i! irn produ''eii a 
plant, \*iiicii Uie say-^; I never vaw to uv. ,., in a i a^o ui 
It- natural teiund.iiion.' So that \vr i.ere tii\e perfect, 
or even more tiian commonly perteii, icrtiiify m a first 
cro>- liet'.verii i\\o di-tiiicl speCie>. 

I'll!- ca-e of the ( riiium leads nu- t<> refer to a most 
smj' ;.!;!., nam»i\, tnat iiier<> are uiur. .titiai plants 
of I crt.iin species ot l<<dielia and of -oine otiier t.'tnera, 
wbu'ii can t>e far more ea-iiy fertiliseu ii\ liie ptdlen of 



another and distinrt >;ppcie.s, tlian bv their own jiolltMi ; 
and all the iiidi\ l(ilI,^',^ of ii»*arly all the spofios of llip- 
piM-trijin M'tMD to In in this j»r«^dira.iuMu, lor tli»*?;o 
iiKints liav»' Ikm.'ii foutnl to yi»'ld mm'(I to flu* |i'il!.'ii of a 
;ii'tiiict >|K'i ii'-, tlioii;;li <jiiito stcrilt' witii tl'T own 
liolh'ii, iiotwitli-tHiHlini;' th:it flifir owii |M>llcri \v;w 
rniiiid to lie jM'rft'itiv irood, tor it fcrtili-^jMl distinct 
-J.... ■!(•«. So tlial rcrtaiii iriili\ iiliial plant- ami all the 
VI li\i(liial> of certain specie- can ;irtiia!l\' i'e h\liri<li-ed 
micli more reaililv tlian the\' can l>e x-lf-fertili-ed I 
I i>r instance, a hulhof llippca-t mm anlicurn producetl 
f 'ir tinners; three were tertiii-cd hy llerhert \Mth 
ih'ir own polleti, and the toiirth \vas «.uh-e(jur:itly 
f. rtili-ed hv the judlen of a coinpmiiid h\l»rid de-cruded 
:r(i!i» tiiree other and di-tiiict -jiecies : the re-ult v^as 
that * tlie ovaries of the three fir-t fhiwer- -oon <'ea-ed 
'n ''r(n\. atid it'tcr a u>\y das- [leri-lu'ij eutireh', whereas 
til'' pod iinjinuii iteil by the pollen of the hyliriil made 
\ ii^i'Toiis irrowth and rapid proijress to inatiirily. :iv<\ 
III. re trood seeil, whi<h veiretate<l freely.' In a h 'ter 
'i> iiic, in li'.Mt, Mr. llerhert tohl me that he had tlieri 
nu'il the experiment duriui; five years, and he con- 
;;niied to try it d'uinL'' -everal >;uli-e;;ieiit \ears, and 
ilwavi with the satne result. I hi- r'e-iilt has. al-n, 
K'cn (.intirnied hy other ohscrvjTs in tlie ca-c of Ilip- 
pi'ri-truii A-itli it- -iit>-L''eriera. and in t!ie c;i-e of -orno 
lit! IT ^renera. as l/)he!ia, l'a-.-iiiiira, and \er'>isciim. 
.\lthMMt;li the plants in the-e experiments iMicd 

per.'cctlv healtliv and althmiirh hoth the o\u:c- and 
p'lUcii ot the same lloucr were j>erfectly t:ood uitli 
re-pei't to other -pecies, yet as they were tiinctiunally 
imperfect in tlicir murnal self-action, we must intt •• 
that the plants wi-re in an 'innatural -tate. Ne\''rtht*- 
It's- the-e facts -how 0:1 »hat slii'lit and mysteritm- 
can-es the leaser or trreatei *'ertility of -pei-ies wlien 
cro--ed. in comparison with tru same specie- w iien stdf- 
fertilised, >-ometimes depeml.s 

i he practical evperiinei'Ls -f tujr^iciiltunsts. thoiiyh 
not made with scientiiic preci-i ui, «'• s^-rve -ome notice. 
It is notorious in how eoniplit 'tod a uif-. iier the speeiea 




of l't'I;ir_'.>iiiiiiii. Tilt li-ii. ( ulrodl.iria, IN'tuiiia, lUifxlo 
d«>!i. ctr., liri\»' i't-rii crnsvcl, yd in.iiiy «)f tlicse 
hyliri'l^ M'l'.i tii't'h-. I itr itist;irn-«'. llcrJ-crt .T^^tTtx tliat 
a livliriii tVnm ( .ilrcolari;* iiitt'irntuli.i .iiHl plaiitatriiica, 
vjMTU'-. iiMi't \n'if!\ i!i--irMilar in l'i-iht.iI liitut, ' re- 
prcxlu. .'i| it>fll as j.frfc.tly a- :t it hail l'i'»>!i a natural 
sMfif's tVotii |)ic iinMiiitaiiis of ( iiilt'.' I )ia\o takiMi 
«ii't.<' 11 ilii- In a-fcrf.iiM tin- <l<';:i-(<' uf fcrlilitv it" sciriie 
1(1 till' cotMi.lcx rru-sf- nt' |{ Ii'mI. nirii'lroii-. ami I am 
assiiro'i that tiri!i\ ot thi'iii arc |(rrti-rll\ tcrt;lt'. Mr. 
( . NiiMi'. Iiir I'l-taiicc i'i;uri!i>- nic tha' !if rai»i'< -storks 
for tr rail in:.'- troin a hvhriil hft\\i'«'n KImhI. I'untiriKii 
anil t ata«hnMi-f. arnl tliat thi- li\ IiphI "s..,'.!, a- trcrly 
a- It !■. posvihlc to iniaLMni'.' II nl li\ hrnl-. whfi fairly 
tn>.i!i''l, f'lni' nil ilfinM~iML' in l'i"-tility in <'aih mic- 
(•i-.,i\o L'l'nr'a; mn. a-" <iir1nfr tH'licvr- to hi- tlic ra-o, 
till* fart uiMild ha\t' hi'fii iioforioii- to nnr^.-rv rniMi. 
f !.)!-tiiM;lturi«t- rai-i> 1 irL'f ImmU ot t'lf >aint> hyhriils, 
■ind -iirli aloMi- arc fairly treatt-d, tor iiy iu-t-rt aL-'f'ncy 
the M'\("-al iniiividiiaU of thi' «;arn«> li\hiiil variety are 
alloucii to fri'i'lv cro-i "ilh cai-li othi-r, ami the in- 
jurious iiitlui-iK-i- of clos,. intt'rhrci'ilin;: i-« tlius pre- 
Ncntt'il. Anv one inav rcniily ronvimc tiinisi-lt of the 
ctlii-iiMicy of insert -aufni'v hy exaniiniiii: the flowers 
^,^' the iiiorc stcrili- kimh of hyliriil riiiMiiMiemlrou-i, 
whiili proiiiii'f no imljcn, for he will tiinl on tlieir 
•-!iunia>; (ile'itv of }>oIleri hrout'ht from other liowers. 
In reL'-inl to animals, iiinrh feuer exjierinient- have 

) II caretiillv trie-l than witli iilants. It our systematic 

arran:.'-eii;eiits can he trusted, that i< if the t-enera of 
animals are as lii-.tinct froii! earh oiher. as are inetrenera 
of plants, then we may inter tliat animal- more m iilely in the s'-ale of nature can i>e more easily 
iTosst'd than in tlie case of plants ; hut the hyhrids 
themselves are, 1 tliink. more sterile. I doulit whether 
anv case of a perfectly fertile hybrid animal can lie coii- 
sid"'ed a< thorouirhlv well authenticated. It should, 
liovse\er, lie home in mind that, <»wniL' to tew ainmals 
hrc'-.linir fn'elv under contiiiement, few experiments 
have iieeii faiilv tricl : for iiisUmce, the canary-bird 



li.i" Immii rro>«>-»Mi with nine otli<>r fiiiclio>, l>iil h« ii(»t 
otif <•! llu'-f" iiiiii' ^jit'i'ij'x iirf«'(i« fri'«'ly iti ronMn'inriil, 
^i have iKi riu'iit t<> rxjieit that iht- tir«.t «Tn«..-.»'> i»«<t»«tH'ii 
ihfiti and ih»' (.mars, ur that ihoir liyhrifi-*. >liiinlii '•»• 
j.rrtVrflv f«Ttil.'. .\;:.i!!i, '»ith rc-p^Tt tn the (Vrtilils 
ri Mii(«'»i\<' L't'iHMati(iii> (it the iiinrt' t»»rtilr h\hriii 
iiiitiials, 1 hardiv kiii>« nf an iii-tainc in «}ii<ii t\vi> 
aiM;lu*> ol the sjinu- liyhriii havj- I>»m'1i rai>-<"<l at the 
- riif titiif from diirtTcnt p irt'ii'.'-. »<) as tu .inml tlio 
'!i »'tf(Mt> ol rl(ist> iiit»'rhr«'fdiiit:. ' 'n th«' (i(\ 
• rnt h«Ts ami -i-tiTh ha\t» usually beon it<»*>»m1 hi rarh 
-. net-oil. e L'tMifiatiKU, in npjiositioi; tu th«' cnti-tantiy 
rf|'i'at«'d ailtiii>iiitli>n «it' v\rr\ )ir('»-d«'r. Ami in tlii> 
. •.!-♦•. it 1- not at all surnri-iiL' that lin- itihcrt-nt 
-triility in th«' hyhrid- -houid iia\e ironf on incri>a>int;. 
.1 Ml- \M';f to act thii-. and pair hn.iht'rs and si>t»'rs in 
•iic <a-i' lit' anv pun- anuiial, wiiicli Croni any cans** 
i, ni tilt- ha-i UMidt-nt v to stt'rility, thf hri'>-d would 
a--i.r»'dly I'O lo-l in a \t'ry Irw j/f ii('rat;o:i-.. 

Althouirh I do not liiiow of any tiiomiijhly \v«'l! 
ai.tinMiticated ta-t- oJ' pfrtVctly t'tTtiU' iiyiiiiil aniinal->, 
1 havft sonu' reason to h^Iiinc tliat ih«' hylind"* tmni 
( irviilijs \;i:rinali>* and Ht'e\f<ii, and from I'h i-.anus 
...lrhiin> vMtii I'. lon|uatiis and with l*. M-r.-itolur ar«r 
■-Tlfitlv t'lTtiU', 'llu-re is no doiiht that tin ~»- thrr«i 
1 ;i»'a>aii't>, nanu'l) , tin' ••omrnon, the true rin^^-netkod, 
.iii': !lie Jajian, inti-rcross, and an- ht'iomimr hlcniU-d to- 
;:i-t!n'r in the woods of several parts of Knifland. The 
l,\liri<is fniiii the ronimoii and ChineM' uee^e (A. 
r',:;noide-), s|ieries which are so ditferent tliat lliey are 
_-e:Mrallv rani<ed in di-;tinct jjenera, have olten hred in 
liii- I'ountry with either pure pareiil, and in one -intrle 
ui-fance they ha\e hred intir .vc. Thi- wa> eHerfed I'V 
Mr. Kvtoii. who raised two hyhriiU from the -aine 
parents h ;t from different hatehes ; and from the>e 
luo ldrd> he rai>ed no les>. than eii:ht hyhri(U (trrami- 
I iiildren of tlie pure iree >) from one iie-t. In lm,.a, 
iiowever, the'-e iross-iired i:ee>e niii»l i>f iai Inore 
fertile; for I am assured li\ two eminently rapahle 
juiltre>, namely Mr. liiyth and ( aptain Hutlon, that 


ON IHK OFtrcilN' OF 8|'K( IKS 


>#hoI« flork» f>( tlie-**' fros<«'<| yrr^o irt* kofit in vKrimi- 
part" ot till' ((iiinlry ; :iti'l .is tht'V arc k»'iit f'ltr prdfit, 
wlioro ii»'itln'r [nir*' |>.irt'iit--|)f>'i('s ('xi^tf, they mii»t 
r.Tt.iiliI V 1>«' ll!iriil\ •'••rt:'ii'. 

A (liM tr;ri«- wiricli m .ciimU'il \*itli l'.ill.i>, li.u* t>«'f»ri 
lartrt'ly /irccyiti' 1 \<v ntiMlern ii;itiir.ili<t«» ; iiHtiwly, tlint 
nu»Nt III (II ; <l(imi».tic ;iiiiTn;il- \\;\\" fi»«>i-i'iiii«'ii fVotn two 
or tnori' ^»iiil -i»i'<ip», since n»iinii;iiu'l»'<i t»y inu-r- 
rrossirit;. ( 'ii tins kii--.v, tin* .•iliori;:iiiil -nn'rirx r -i-t 
eilliiT lit iT-t li;ivc iiDiilurcl ijiiiU' fi^rtiln hytirid^, or 
till' liyliri.l-^ iiiu«t }i;ivf l.fcMtiii' in >.iili-i'i|u»'tit jfi'iuvi- 
tioiH <|wili) tVrtiU' iiii'liT liouH'stnvitiiM. I li;s |.-»!»»'r 
altiTiiativi' »iM'iii-« to iiii» tlic nmst jiroiiiliii'. iini 1 .irn 
:iitliii(' I to lii'Iii'ii" ill Its truth, ;tllh<Miirli it r»'-ts on nn 
(lircrl i'\ iiii'iirc. I hcl'.",»'. tor iiHtanrp, tliat our <h>irs 
have ih'-v.iMiili'd from -f.crai vvjhl <tcM'ks ; vt . with 
[MTliaji- till" t'xi'rptiuii ot rcit.ini inilhTnnus (iomc^tir 
lioirs of >oiith AniiTiia, all :iri' (|uitc i»>rtil«* toiri-thcr : 
ami ai;il'i;\' ni.ikt's mi' jrca'l}' ihtuiit, wlicthi-r the 
•.(•vi»r;il ahi.ri:,'iii il -|ii'rii'v nu lid at hr>t liav«» trci'ly 
lirt'il toLTi'tliiT ami li.avc |iri«ilu.'C(l .juiti* fi-rtili' tiyhriils. 
So ;i.'-aiii thiTc i>. ii'a>.on to h<'!i('\i' that our lOiropcin 
ami thf liiitntii'il Imliaii ••attic art' ijuitc tiTtih' ti'ii-i-thi"- ; 
liut trmii tacN iiiiiniiiiiiiratfil to iiii' hy Mr. Blytli, 1 
tliiiik thi-'. iiiiist hi' con-MliTt'ii as di-timt >pi'ci«vs. On 
Miis \ icw ol ! ii(> ori^'in of iikuiv of imr <ionii'--tii' animals, 
we iiiii»t I'ifhcr tri^i- up tli(' i"'lii't oj the aliiinst ii:i!- 
vi' -!■■ iiity of (li^tim't s|ii'cii'- of animals when 
(TO— ('(i ; or we nui-t look at sterilitv. not as an in- 
ih'lilih' ■ h iiii-teri-tic, hut n- one eapahle of heinp 
reiiiiiM'd hy (lumr^tication. 

I'iii;iil\-. lookinir to all tlie a^rertaineii :att- t<\i tin' 
inti'rcro*-'!!:^ ot plan's and aipmals, it iiia\' I'e i oncliided 
tliat -.oine ilejTci- of ^terilit\. h"th in first crosses and in 
livhriil-, i> -in evtremely ireneral result ; Imt that it 
cHTUio! . nnder our present >tate ot kno« ied^'e, he con- 
sidered as atiMilutelv tiniversjil. 

Ijiirx govfrniiiii (hf Xrri/ity of first t'rosxt^s and of 
lli/hrids.- We will now consider a little more in detail 

i : 



th«- nrcumfUiticfv .-ukI rule- iin\et:]iuii tii.' ^.tonlify ol 
tirnl cnisscH ami ut h\ Itrids. < hir thiet"«>lM«'<-t will \>v to 
see whi'tluT or not the ruU- iii<lir;itp tliftt -jtf . if 
*}.«•«■. alU li»'»'n omluwr.l witli tlii- iju.ility. iti onlfr to 
{•recent thnr iTo-o-inr ami lilemlintr locetlier in uttor 
I "ii^ll^il>Il. I lit' ttiiidv* iin; rulr-* ami tooi bi-ioiix .irf 
I I t tiv <ira\*M ii|» t'toin (iirtner- a«liriiral>lf wirk nii \ho 
lij |jrilii<^atio!i ol |)i.uit>. I have lakt-ri njiuli |.aiiiH to 
i"'«'rtaui how far the nil<'?< ajii'ly to animals, ami con- 
-. .»T.j.ij Ik'W M-aiity our kriowieil;;*' is in rrirartl lo 
h\ti!.ii anmipJ'*, 1 liav«' Immmi siirjin-fd to tiiid lio4» 
iTfiiiTallv tin* !*amf rules ajiplv to Ifotli ixiiii;tli'm-. 

It lia-j l.«MMi already remarked, ttini the (le::ree of 
t.Ttihtv, h.tlh of hr^t t rirfsfH and ot' h\, hrnl •>, tradua-.e-f 
liHin zero t<> ;>f;If»t fertility. It i> «i!rjir)-ii.L' in how 
i!i.i:iy curioii'* w;ivj4 this tjrailation ran l>e 'hitn!i l<i 
f\''t ; hut oi'lv the tinre^t outline ot the fart- tnti 'uere 
Si« ifiven. \\ iit'M [lollen from a plain or due tamily .h 
].] i«ed on the <lii.'nia of a idant ot" a diMiiict tannly, it 
('\erts no more iiiMiieine than "o much inoriranic dii-t. 
Iroin this ai'soliite zero of" fertility, the jiolien of differ 
. lit "iKcies of the same L'enus aiipiied to the >ti:.Mna of 
-ome «»ne sperie", yields a perfect crailation in th» 
in:.'. her of seeds jtrodured, up to nearly complete or 
even <juite complete fertility ; and, as we ha\(' seen, iu 
trtain ahiiorm il tia-es, even to an excels oi fertility, 
he\oiid that v^hil■!i the ].!aiit n own pcdien will produce. 
r •> in liylirids them-ehes, there are soine wliiili np\er 
l,.ive pn,,!, red, and pruhaSiy ne\»'r would proiluce, 
even with the pollen of either pure parent, a ^'inl.'le 
teriile seed : hut in some uf tiic-e la-es a tlr.-t trace of 
lertiiily may he tieteited, hy tlie pollen of(uieofthe 
jiure parent-species cau»insr the o? the hyiirid to 
-^iher earlier llian it other'.vi--e would li.i.c duiic ; and 
'he earlv vuthering of t he flower is «ell known to lie a 
- irn of ' iii'ipic'it fertili-ation. From this extreme 
:ci.Toe of sterility we have self-ferr:ii-eil hvliriii- pro- 
duciajr a ^rreaier and K^oater numher of seeds up to 
lT:e<-t fertility 

Hybrids from two Bpecies which *rc .ery difticuit to 



cro<w, and whi<-li rnrolv proHiico ariv off^jiriiifir, are 
K-enerally very ^iU>rile ; Imt tlie parallfli-in li«'twccTi tlip 
'iirtii iiltv of niakiiiiT a tirst cross, ami llio storility »t flie 
hvuriil^' thus product-fr • two cla.-st's of' fait'^ *hi(h ire 
i,'»*in'rallv contuunilt'fl Uiir"'lior :■< by no m<vins stri-t.. 
I lnT»! ar»» niaiiv cast-s, in v incli two p'lrj' Hpt-ni-y • iii he 
Hinted witi' inui.iiial fa<-!lity, ;»nd iwm.J'ko uunifrourt 
hv(irid-'i!T-.,>rinir. Vft tln'-e )iyt>rid-i ire 'fniarKa'dy 
«terilt'. < ''I tlie nt!;er liaiid. there are «pei-ies '-vliKdi 
ra!j We (•r<>--.eil verv rarely, or witii ertreine diificulty, 
lujt tlio tiv'Tids, wlien at last prodin-fd, are very 
fertile. Kven within tlio lirnita ot'tlie same irenu^, ror 
instamo in Di.itilhti.s, these two opt(o--ite ciL-es oii-'ir. 

I'lie tertility. Ixith nt' tir><t rrosM's ari'l ot hybrids, in 
more easilv atfectefi by iinfavoiirabie coMilitio!;-. tlian 
is the I'ertiiitv of pure sjMMies, Kiit ttie deu'ree ot 
fertility is likewise irniately variable ; tor it is not 
aN.i\-> tiio -aine when the s;iTnc two sjHM-ies are eros-ed 
'ludiT the ^arne eirciunstanees, but dei>ends in [iirt 
upon tlie fonstitiition of the individwals whieh hayij'fn 
to have been chosen for the expernnent. ^«o it is wi«h 
bybridw, for their detrreo of fertility is often found in 
differ (jreatlv in the -everal individuals raised from seed 
out of the -ame eapsulo and exp'ved to ex:\ctly tlie 
same cotiilitions. 

Hv Uu" term svstematie affinity i» meant, the re>ein- 
blarice between spet-ies in utrueture and in lonstitution, 
more e-pe< i.illv in the structure of parts wbicli are (jf 
hiirh pliv-iolo^'iral imjmrtance ai'.d *hicli diib'r li'tlo in 
the allied species. Now the fertility of ririit crosses 
Vh'tweeii spe4'ies, and of the hybrids produ<ed from 
them, is lareolv iroverned by heir systemauc atfinity. 
Ihis is clearly -liown l)y hybrids never having been 
raised between species ranked by systeiuatisLs m 
dUtinct famlien ; and on the other band, by very 
closely allied speeies generally uniting- .tith fariiity. 
Hut the oorre«iK)ndenco between systematic affinity 
anil the f:i4-ilitv (d'crossiin; is ()y no means strict. A 
multitude of cases could be eiven of very closely allied 
B]>ecies which will not unite, or only with extreme 



dilfiiMiltv ; and on the other hand of vpry distinct 
)in'ci«>s whirli iiiiit»> u itli the ulni(>>t facility. In the 
s;tnie fHriiily thfie may W a tr*Mius, a.s Dianthus, in 
which vtTv many >j.c. ies tan Tni)>t r»»a(iily l>e iTossvd ; 
fuid aiKitli.T -t'l.iis, as ^lit-iic, in whirh the most 
i.prst'vcriii!.'- ethirts }ia\H taiU'd to [.rodiico h»'t\MTn 
r\lr«'nicU ciuM' >|.ofi««.>. a single hyt>nd. Kv»mi vsitliiu 
tl.o limit's of tho <iino e»-inis, we nu'ft with tlii^ -ame 
.lirteri'tii-e ; Inr iii>Uincf, the many s|)e«ii's of Nicotiana 
have i'l-en more lar;r»'ly .-n.-i-od' than th.' species nt 
ihnost aiiv iitiicr irenus ; '■ut (iarfntT tumid tiiat N. 
aciiininara, v^il;cil is not a particularly distinct si.ecien, 
ohstmately faUed to fertiii-e, or tr» he fertilised hy, no 
ie«s tliaii eitrlit otlit-r sjie, les nl Nict)liana. 'very many 
ai'alotfous facts could he iriven. 

No ftiie has lieeii ahle to point out what kind, or 
what amount, of diiiereiice in any recnjrni>ahle cliar- 
acter is suriicient to prevent two species erossiiuf. It 
can he hliowu that plants most widely ditfereiit in hahit 
and ireneral appearance, and haviiitf strongly marked 
ititlereuces m e\ery i)art of the Hower, even in the 
i.olleti, in the truit. and in the cotyledofis, can h« 
crossed. Annual and perennial plants, deciduous ami 
evertrreen trees, plants inhahitini^- ditferent stations and 
!itte<l for extremely diiierent cHmates, can olten l»e 
crossed with ea^e. 

Uy a reciprocal cross l»et"fen two species. 1 mean the 
ca-e, lo' in-tance, of a stallion-horse heinir first cros^eii 
wth a female-ass, and then a male-ass with a mare: 
tlipse two ^pec1es may then 1»« said to have heen recii>- 
rucaily cro»e«i. There is often the wide-t possible 
dii'erence in tlie facility of makiiijr reciprocal crosses. 
J^uch ca^es are hi^rhly important, for they {•r(»ve that 
the caj>acitv in any two species to cross js ot\en com- 
pletely independent of tlisir systematic affinity, or ot 
any reconni-alde ditfcrence in tlieir whole onranihation. 
( >ii the other hand, these clearly show that ihe 
c.ipacily for cror;>in>f is cOuucetcti With eiJiie-tit'-itM'-f-'i, 
diiferences impercepiihle hy us, and confined to the 
repro<luctive system, lliis diifereuce iu the result of 




I 1 ■ 


r»'i i[)r(ic.-i! (TO^i-i's l>«'tMe«Mi tiit^ >.irii(« t«o >{) wa^ 
loiJL'' MiT'i (i(i-('i'vi'(l hy Knirciitor. In t''i^<' an :ii>itaiiop : 
.Miniliili< jalajia ran cavils he N'rtili.-<'(i liy the pnllcn nf 
M. Iniiifillora, and tiir )ivliri(l> thus pr(i(l!|i'c i .ire 
sii!ii.ii'iitl\ f'rrtili- ; liut 1\ Iii-iitrr tried more t!i:. . t'.vtt 
liiMnlrcd time-, (lnri;;i' ci^lil i<il!o\\ iiiir voars, t»> ftTliiise 
rt'i'i|irncally M. iDiiL'.lli'ra .\itli l\\v |h)1jpu <ifM. lalajia, 
and Mttcrly tailed. ><'\»Tal other fi|'ialiy -trikiiit: *'a^e!- 
ndihi 1h' iJi^t'n. Thiint ha.'- i)h-i']\ cil the aaiiie ta<"t 
with I'ertaiii -<'a-;N I'i'ds ui- I'lici. (i rtacr. iiir)re'j\er, 
Iniind tha!. this difierenet' .4" facil:t\ in luakinur re- 
(•i|>riMal rr<i>>es is exlreriiely • nminnn in a h'--<er decree. 
He lias (iliservrd it e\eii helueen f'urrns >n « h(s»dy 
rolated (a^ MatUiirda annua and trhihraj tliai many 
lM»taiii-ts rank ihein only as varieties. I', i>. al.-o a 
n'lnarkahle fact, tliat hybrids raided from reoiprocal 
cT(»->es, th(Hi::h ni tour>e i-dinpoiinded ol the very same 
two species, th« one sj)pcies lia\ iiiij first heeri used aa 
tiie father and then as tlie mother, t'eneraUx ditler in 
fertility in a small, and oicasioiially in a hitrh deirree. 

Several other singular rules could lie tfiven from 
(iartinr : lor instaiH i*, some species ha\e a; 
power of c-ro-sin:r with other s| ec ie.> ; other >p"cies of 
the same jn'iius have a remarkalde power of impres.sinir 
their iikci.ess on their hybrid otrsprinir ; hut the>-o two 
powers do not ar ;ill m^cessarily ^o t<i:rethpr. There 
are certaiii hybrids which instead of havinir, a.-' i.s usual, 
an intermediate character between their t^To parents, 
always cli)~v''\- re^eiiille one of them ; and .such 
hyhritls, thnui^h externally so like one of tln-ir pure 
parent-~:>ecies, are with rare exceptions extremely 
steiile. So aiT-iiii amontrst hybrids whi( h are ■isiially 
iiitci II ••di.ile in structure between their parents, ex- 
ceptional and abnortiial ii'riividuals sometimes are bnrii, 
whii h clo-ely resemble one of their pure narents ; and 
ilie^e hvliritis are almost always utterly ^teriie,e\ en when 
the iitlier hybrids raised from seed trcm the siinie capsule 
have a coiisideraide det^ree of fertility, i iiese fads show 
how ((mjpletely fertility in the hybrid is indepeiideut of 
its external resemhbnce to either pure parent 




,V i': 




("oiisiilrT intr tiu' -Ji'viTal r\i\(^ now sri\pn. whitli 
(.'•vprii tho lertilit;, of ur>i cn^-sos and (it' hy'hriiis, ue 
-;c(' tlia* wlu-n forms, whiili inust iie • i-iisuiorfd :i^ tr<'0<i 
\u<\ iii-t;nct -[io<-it<, art- luiited. tlieii UTtility t:r:>il nates 
t.iiir zero tn ;'>'r!('i-t f»Ttility, or even *o 'Vrtilit) iimU^r 
'•■:,;. in (Moiditiniis in ex>"t'ss. 'Hiil their fertility, 
I..'- (ic* lifiiit/ t'Diuit'iitly -.u-iccptil'le to Livourr-i'le and 
i.i.i:i\(iur,iiik' ton.iuiiiri-i. is iniuitcly \:in:ild»\ i iiat it i« 
\i\, nil means aUvavs ilu- siinie in d»-i.Tee in tlie fir-t rros.s 
ciiid in the liyiirids jirraliu-ed from tiiis tnivs. '1 liat the 
t.rtility ot hyl>rids is not rehited to the ilr;:ree m 
*liich thev in cMtrrial appearance either 
parent. And lastly, that liie facility ol making a hr^i 
ini>s between any two specie-' i--* not always t'o^erned 
I:.- their systematic aff.nitj or de?ree of re>enihlancr to 
i icli (ither. Thi" latter ^titcment is elearly proved hy 
toiipt'ical cros'-e.s hetween llie same two species, |i»r 
,111 ordiiijr as the one sj»e( ies or the other is used as the 
I ither or the motlier, there is generally some diiTer- 
tiie, and occasionally the widest po^^illIe diiier nee, in 
!.c facility of effedintf a union. i he hyhrids, inor» 
<:\i':-, pro<iuced from reciprocal crosses often differ in 

Now' do tliese complex and sinjrular rules indicate 
t' species have lieeu endowed vv,th sterility -imj.Iy to 
I .event their hecomintf confouiHicd .n nature.' I thuilt 
I it For why nhuuld the sterility he «o extremely 
(1 liferent in detTee, when various species are cro.s,se<i, 
, M of whicli we niuj-t suppose it wnuld he ♦Mjually im- 
p'litaut U) kt» p from blenduitf to^^eiher.' W ity should 
tiii' de^rree of sterility he innately variable in the in- 
dividuals of the same specie.-.' \\ hy >hould some 
species cross with fa. ihty, and yet produce sterile 
h\ tirids: and other sperit^scro^s with extreme dithculty, 
and yet produce j'aii iy fertile hybrids.' Whyshould there 
f'tien be so trreai aditierence m the rejiult of a reciprocal 
cu>ss between the same Iwo species .' ^V'hy, it may 
tM II tie asked, has the produeliuii of hyonds Dcen per- 
n.ilted : to ffrant to species the Bperial power of produc- 
ing? hybrids, and then to stop their furtlier pro(>»^tiou 



^- ^*::-'r;; 

•'i.a^;^:/.^:i-£Si. 'J'.% i &--M 








\>y (litfoHMil (ietrroes of >t»!rility, not -iriitly r(>l.•^^<•d to 
the facilitv nf the first union lielweni their jiareriti*, 
ec('ni>< to l>e a str.iiiire arr.'iiiirenu'iit 

I tie t'oreiroiiitf ruN^s and fVii t-, dm 'hi- othtT h;iii<i, 
-ipiie.'ir to rue I'U-.iriy to iiiiii'-;i;t' th.i' tlie -iteriiitv tioth 
of iir^t i-ro>v('> aiiil ot ii,liri<i<i in sinijilv iiicnitMital or 
liept'tuieiit on inknown ilirf:>rence<. i-liu'lly in the r»'nri>- 
rliictive xy-^N'tii-;, ol the '^jiecie-i wliirl, -ire crosvod. I he 
•litTereni es 'nitiif ot >io peruliar hihI liitiitt-d ,i nature, 
'iiat, in re"i[iroi;il ir<>-M-s 'letwfrn t«o -pi'ii*'^ flie ni.ile 
«<;xu;il f'li'iiien! of tlic one \*ill nffjMi tVi-elv act on the 
tetnale scxu-il i-i.'nifnt of Hie mMut, hit riot in a re- 
versed direction. It «ill lie advi«.aide toexplini a little 
more ttiliv l>v:in example wliat I mean hy sterility ')ein(r 
incidental on other ditVer*»in'Hs, and iii't a •"piM-ially 
endowed qualitv. As the cajiacity of one plant to be 
ifrufled or hudded on anotlier i^ >^o erjtirely unimportant 
for it^ weli.ire in a staU* of nature, I pre-ume that no 
one will >-iipp,we that tiiis capacit)' is a "jifi-iuHy en- 
dowed i|u.ilitv, !>Mt will a<lmit that it is imidental on 
differences in the haws of trrowlh of the two plants. 
\\ u can ■.ornetimeH so« the rea-*on vvhy "ne tree will not 
t.ike on ah 1. 1 her, from diirerences in their rale (d'trro-* th, 
in the hardness of their wood, uj the period <d the flow 
or nature of their sap, etc.; hut m a multitude of cases 
we can i--i^'n no rea-on wh;ite\er. Oreat liiversity '\\\ 
the -iize of t^o plants, <»ne heintj woo<iy and the tdher 
herhaceous, one lieiii;^ e^cnrreen and flu- other de- 
ciduous, and .idaptation to widely different cliniates, 
does not alwav" prevent tht^ two f^raftinu'- toilet her. As 
ni hvi'ridisiif :on, >o vvith trraf'tinj.', tlie caitacity in 
limited hy sv^tetnatic atrniit\ , for no one ha- heen ahle 
t») trratt trees 'ouelher h« ionirinir to (piire <li->tinct 
familiesi ; and, on the other hand, tlosely allied species, 
and varieties of th" same species, can usually, hut not 
invariahlw he irrafted with ease, liut this capacity, as 
\n hyhriilis.ition, is hv no means ahsolutelv K'overned hv 
Hystematic affinity. .Mtluuiffh many distinct ^'eiiera 
within the same family have been trratted to;rether, in 
other ci>es species of the same ^,enu» will not take oa 



each other 'Hie j»par can l>e irnifteti far more r^ailily 
on the '^'iitire, wIip h is ranked a.-* a dixtinct ir»«miH, than 
on the ipple, which is a niemher ot" tlie same jrenii.H. 
Kveri <iitirr»Mit v^riotie-s ot tlie pear t-ike with different 
dejrrees of facility on thequinre ; so do different varie- 
ties of the apricot and peach on certain varietiej^ of »}i« 


As (JirtTier found that tliere was soinetiiiie-* an innald 
difference in different in 'ii'^duch nt the saino two 

apecies m ( ro-^sui^ ; 

•«o SaL'aret believes this to he the 

case with d'r?erent individuals nt the same two specie* 
in Vieinif jf rat ted tcirethor. A-s in reciprocal erns-es, the 
tacilitv of efi'ectiuij an union is nftfti very far from 
e'lual, so it sometimes is in trraftinu' ; <lie common 
jrooseherry, for iiiitanre, can- t he g-rafte<l on the 
currant, whereas the currant \*ill take, thouifh with 
difficultv, on the pooseherry. 

We liavo seeti that tlio stflnlity of hvhrids, which 
have their reproductive ortranu in an imperfect con- 
dition, in a very different case from the difficulty of 
uniting- two pure species, which have their reproductive 
or:-ans j»erfect ; yet these two distinct cases run to a 
certain extent parallel. SomethinjT analoirous occun* 
in irratlinjf ; for lliouin founil that three species of 
Kohinia, which seeded freidy on their own nM)ts, and 
which cnuhl ^>e srratted with no d fticuity on 
another spe. ies. wlien thus frrafte<l were rendered 
harren. I >n the other hand, certain specieji of >^orhus, 
wht>n erafted on other si)ecie«, yielded twice as much 
fruit xs when on tlieir own roots. We are reminded 
!)y this latter fact of the extraordinary case of Hippe- 
rv'^trum, i,*)!telia, etc. , which <«eede<l mucli more freely 
when fertil>'«<l with the pollen of distinct species, than 
when s«'lf-fertilised with tlieir owti pollen. 

NVe thu* sw, that althouirh there in a clear and 
fundamental difference between tlie mere adhesion of 
^r;i!te<l stocks, and the union of the male and *"emale 
elements in the a«*t of reproduction, vet that there is a 
rude deirree of i>arallelism in the results of jrraftintf and 
of crouHUi^ distiiHt specie!*. And as we must look at 

I i 

i I 




th»* ciiriuiiB aii(i coniplcx laws jroverriinjc tlie facility 
with which irtM's can he i.'r;ilLe<i on eJich otiier ;is in- on unknown (iirlcrencoH in their vfirt-tafive 
fy.-lt'iiis, ^() I ht'iieve tliai thi- still more connjln lawn 
^ovcrniMir tlic tin liity ut lir>t cross*** are incijeiital on 
.inkiiowii (iiilVrencfS, chicfl) in their repri»uuiti\e 
•iy>.'.'Mis, I ht-f (iiiicr»'nco>', in hoth ras^s, follow to a 
teruii Hxtont, its iniiiht have ln-fn e\|ii'i ifij, systen.atic 
ahiinty. nv wliith «'\pry kiu<i of re>enihi.-i!,re and dis- 
Biniil.irur t)ctwcen urtranic hoin^s in altcrnftteti to he 
ex[ir('sHe«l I he hi' ts tiy no niean:i KCt-r . to me to 
1 idirat»» tlint ih( j^reater or h-sser difiu Uily ot «v.ih»'r 
^raitii.j; or croK^inff lojrcthor \arious spct iph Iiju' heen a 
siteciai f»n<iowineut ; altiioiipli in the can© of cni-tsinjf, 
tli»* (i.tfu ulty i>* an imp<iri.;nt for the endurance and 
Hi.ihiiity of sjtecihc form.-, as in the rase of ^^aftiuJ{ it ia 
uunni»oriant for their welfare. 

('anxfii of the Strriiity of fimt i'romes and of Hyhridn. — 
We may now hiok a little closer at the prohahle causea 
of the sterility of first crosses and of LyhridH. 'Hicse 
two ca>es are fundameutally dirfereut, for, as iust 
remarked, in the union of t«o pure specien the male 
and feinaie sexual elements are perfect, whereas iu 
hyhiiiU ihcy afe impertect. Even in fimt crosses, the 
ercalcr or h-^er diiliculty in effecting a union aj>- 
pareaily defteuds k.iu ^everal dist>mt lauses. i'liere 
i.uif.t sometimes l»e a phy -ical impossihility iu the male 
clt'iiiciit reaching the ovule, as would he the ca>e with a 
I'i.tnt havini,' a [d^til too ioiiK for the poileu-tul)c-. to 
reach the ovarium. It has also been observed tliat 
wiien poilen of one s|>ccies is placed on the stiirnia of a 
di'.uiictly ailied sjtecio, thoui:h the pollen tube« pro- 
trude, they do not i>e:ietrato the sti^matic surface. 
AtThin, tlie male eleiiuut may reach the temale element, 
but he incapaiile of causinsj; an embryo to bo dt veloped, 
ttji aiipniM to ha\ e been the ciise with some of i buret s 
experiment* on Kuci. No explanation can be ^-iveu 
of these fact«, any more than why certain trees cannot 
Xtv ^aft«d on others. I,A8tly, an embryo may be 




developed, and then perish at an enrly period. llih 
latter ;ill/»r:iativo has not l>oen "ufTiciently ;itt^n(1pd 
to ; but I t"*lievp, from o!i>»»>rvations roniniumiat*<1 to 
mo by Mr H«'witt. who haH had trrfat oxporieTire in 
liybridi-iinjj rallinaceoux hirilH, that the parly death of 
•}i'> f-mhrvo i'i a vory fri'<iiie!:t raii«p of ^ter.lity in first 
•Tos-ies. ' I was at' fir<t very unwillintj to U-lievc in 
•'lis viow ; a.-! hybrids, when once borti, are irenorally 
hcalthv and lonjr-lived. a- ^c -o<» in the case of the 
..iminon miib>. Hybrids, howe^or, are ditfcrtvitly cir- 
. umstaiiced before and after birth ; when Uirn and 
hviinf in a country where their two parents can live, 
■iiPV are jrenerallv placp«i under suitable conditiotis of 
,1'e. But a hybrid partaken of only half of the nature 
i:iil constitution of ita mother, ami therefore i)efore 
'..rtli, *.•< lontr as it is nourished within its mother's 
nomb or within the eea or seed produced t.y the 
•Mother, it mav he exposed to conditions in some (leirree 
i!:-uita!.le, and conseiiuentlv be liable to peri-h at an 
lily period ; more especially as all very younir iK'iiiir>' 
(■'■•n eminently sensitive to injurious or unnatural con- 
iitioTjs (if lifo. 

I;i reirard to the sterility of hybrids, in whicii the 
-e\ual elements are impenectiy de\elopHd, the case is 
. erv ditferrnt. I have more than once aflrdcd to a larpe 
. .d'y of facts, which 1 ha' e collected, sli,)\vir!L' that 
•A hen animals and plants are removed from their 
' .I'liral conditions, they are extremely liable tr) have 
iicir reproductive systems seriously ntb'cted. This, in 
'i-t is tlie trreat bar to the domestication i>fa!!imals. 
H. 'tween the sterility thu- -uperinduced and that of 
':\brids, there are majiy points of similarity. In buth 
ca^es the sterilitv is imiepeiident of ireneral lieiilth, and 
1' often accompanied by excess of size or trreat luxuri- 
;iiicp. In both ca-sps, tlie sterility occurs in v.-irious 
'icL^rees ; in both, the male element i- the most liable 
to Ke .-iffcoted ; but sf)metimes the female more than tlie 
male. In both, the tendency poes to a certJiin extent 
with systematic affinity, for whole croups of animals 
and plant.s are rendered iminttent bv the same un- 




natural conditions ; and whole groups of s[»erie« tend 
to produi-e sterilo hyJiridn. On llio othtT h.ind, one 
Hpefios in a ffroup will Koniptinic>> r»'-i-t t:rwil chanj^es 
of conditions willi uninn>airt'd fi-rtility ; and certain 
species in a trroiip will produce uniiMjally fertile 
hybrids. No one can tell, till In- tries, whether any 
[(articular animal will hre»'d under conlin«'tneiit or any 
exotic plant seed freely uniler culture ; nor can he tell, 
till he tries, whether any two species of a jreiius will 
produce more or less Kterile hyhrids. {.a^tly, when 
orjfanic Iteintrs are jdaced duriii seNcrnl L'cncrationH 
under conditions not natural lo tiicm, they are 
extremely lialile to vary, wliich is due, a- 1 Udiove, 
to their rej»roductive systems havintr lieen sp«'i ially 
atTected, though in a lesser de;jree than «hen sterility 
en^^ues. So it is with hvhrids, for hyhnds in successive 
generations are eminently liahle to vary, ase\ery experi- 
mentalist has ohserved. 

i'hus we Hce that «hen org-anic hein;r> are placed 
under new and unnatural conditions, and when hyhridft 
are produc»'d hy the unnatural crossiiitr of two species, 
the rejiroductive system, independently of the ^'^eneral 
state of health, is ariected hy sterility in a verv similar 
manner. In the one case, the conditions of life have 
heen disturhed, though often in so sli;:ht a detfree as to 
he inapprecialde hy us ; in the other ca-e, «»r that of 
hylirids, the external conditions have remained the 
Kiime, hut the ortranisation has hcen di-'turhcd hy two 
ditferent structures and constituti(»ns havini' heen 
hlended into one. For il i.s scarcely possihle that two 
organisiitions should he coni|>ounded into one, without 
rtome disturhanco occurring in the development, or 
periodical action, or mutual relation of the dilferent 
jiart,* and nrtrans (»ne to another, or to the conditions of 
life. N\ hen hyhrids are aide to hreed i;i/cr ac, they 
transmit to their otfsprinir from generation to fjene- 
ratidii the same compouniietl or^^anisatiou, and hence 
we Tieed not he surprised llial iheir steriiily, tiiouf;ii iu 
some de^free variahle, rarely diminishes. 

It must, however, he confessed that we i:atuiot under- 



ptand, exceptiuK on vatjue hypotlieses, Hever&l facU. *ith 

resj.<H-t to the sterility nt hy!»rids ; tor iii<taiu-e, tlio uii- 

P<juiil fcrlilitv of liyhrids' produi-ed from rprij.rocal 

rro-s('s;or t'lif iiirreased stirility in tliose h>hnd9 

v^liuh orcasionallv and exi-«'ptioiiall\ re>«'inl>l«' • lo-ely 

.-itlier j.urP pan-ii't. Nor do I prct.-nd that ihe fore- 

j-oirit: remarks yo to the root of thi- niattt-r ; no ex- 

[.laiiation is otirred why an ortrani'in, wlirii jdaced 

iiiiU'r unnatural (•..n.lit!oi:«, is reiuh'rtMl sterile. All 

•hat 1 have attempted to show, is that in two oases, in 

-oine respeit.s allie.l, sterility is theeommon result, in 

I he one case from the conilitions of lile haviiiL: heen dis 

turhed, in the other ca^e from the organisation havinj< 

heeti disturU'd Kv two oreani-at ions haMni.' l>e«>n rotn- 

l»..uiide(i into one. 

It may seem faneiful, hut 1 Huspect that a Mtiular 
parallelism extends to an allied yet very diiierent rlags 
.,1 tails. It is ati old and almost univer>.il helief, 
t.iunded, 1 think, on a con.-iderahle hody of evidence, 
that siitrlit chanL'Cs in the condilinii.s of lite are hene- 
l.rial to all livintr thintfs. U'e see tins a.led on hy 
tirmers and trardeners in their fre-iuent ex. iiaiiires of 
seed, tul.ers, etc., from «»ne soil or climate to another, 
Liid iiack a;: lin. Durinir the convalescence of animals, 
wf plainly .see that L-^real henetit is derived from almost 
any chan'ue in the hahits of life. A^Min. with 
plants and animals, there is ahundant evidence, that a 
cross hetweeii very liistinct individuals of the same 
vpt«ies. that is het«een memhers of diiferent strains or 
suh-hreeds, trives vi;r,uir and fertility to the ort-.printf. 
I hciicve. indeed, from the facts alluded to in our 
fourtli chapter, tiiat a certain amount of cro-inu in in- 
ili>pensahle even with hermaphrodites; and that cl..->e 
■ nterhreedintr continued durui^ several p-neralions 
i..t\M'en the nearest relations, especially if the-e he 
Kcjit under the s.ime conditions of life, aUays induces 
wt'.ikness and sterility in the progeny. 

Hence iL seeing tnat, on i:-v uiic li.^n'i, r::^!.v 
cliatiires in the conditions of life henetit all or^'anic 
Iteiiiffs, and on the oliicr hand, that blight cross**,, that 





la crfH«pv l)(»tw«'eii tlie m.iU's aiiM ft'niaipi of tlio ^ame 
•iptM'icJ wl:ii'i hnvo varit'd ami it'cotTU^ »Iirhtly 'lif- 
ffrciit, L'i^*' viroiir ami tVrtiliM 'u flic nifvpriiiif. I{iit 
wo |ia\»' sifri that ifrt'ater iliaiiL'i''*. or . Iiaii:re» "f a 
particular nature, ottfii rRiider (iriraiiif hciiiirs in somn 
'ioi^rct* >t«'ri't" ; arni tliat trrt-ater tr<>-"«'^, i< .t"-^''-* 
Sc'wiMMi inalcM and tVm ilo whi-h lii\e Konnie wi<l<'!y 
or specifnally (litlort'iit. jir«»<i'i''o >iyliriiU whifh are 
L'f'it'r.i!! V «t('ril»* in sonu* il<':rrec. I catimit I»or^ua'io 
my-t'lf t'lat this parallt'li'-iii !s in aniiiiMit oran illusinii. 
h(il|| ?t 1 ii's of facts- s«'»'in to 1m> cititU'ctiMl t I'tlu'r hy 
somp cofinnori l>ut ntikiKm-n lioii'l, ^iiich i~ -sentially 
rolaUvi to the principK' of life. 

Frrtiiify of I'urifth s irli^n rrnsMff^ ,nifl ot'thi-ir Mtni'irfi 
ojfxpriii^j. — It may !»♦» uru'^fil, is a iT'.ost fori iiilc art^ii 
mcnf, that there must he -tmi" e sential flistinetioii 
hetweeii -jicrio> ami varieties, au'l thai there must he 
woiiie error in all the foretroitiir remarks, inasmuch as 
\arieties, however much they ni.iv differ from each 
other in exfcrna! a|»j)earance. cro-s with perfect facility, 
and yield perfectly fertile otf-priii:;. 1 fwlly .admit 
this is almost in\aririlplv the e.'ise. But if we look to 
varieties jirttdiiced umier nature, we are im"M'iliately 
involved in htipi-less ditliculties : for if two hiilierto r»^ 
jiuled \arietifs he found in any deurree sterile tni^i'ther, 
the\- are at once r.inl.t'd t'V most naturalists as >pecies. 
For instance, the Mne and red ]ii'!ipcrnel, the primrose 
and ciiw-lip, which are coii»idered 'i.- invny of our he^t 
Ixitani-ts as \arietie-, are s.iid hy (iartner not to l»e 
quite fertile when erosse<l, and he conseiiuently ranks 
them .'!> undouhted sju'i-ies. if we thus ar^'ue in a 
circle, the fer'ilitv o. .all varieties produced umler 
nature -.vill assuredly lia'/e to be trranted. 

if we turn to varieties, produced, or supposed to have 
Ween produced, under dome-tication, we are still in- 
volved in douht. For when it is stated, for instance, 
tliat tho (ierman Spit/ dojf unites more e;isily than 
other <iot;s with foxes, or that certain South American 
indigenous domestic dotrs do not readily cross with 




nVMIt 'iSM 


i-iiroj)ear) di>tr>*, tlic o\jtl.iii.i'ii)ii wiiiih will nri ur ti) 


1 \ t'r\' <>:it', ;ii,(i nrnlial'lv tlic iruc n;'", i~ tliat tli»'»<> 
(lnj-> liavt' <ic->< einlt'fl triiiii »i'\rr.'il al'i'ri::iii.ill\ lil-titict 
-jn'fij's. N(". »Mtlit'if»< tlic jit-rli'.f I'l'itiiity <'l " iiiaiiv 
iii)iiu'-«tic \aiioti('s, (iitloriTij; widciy t'rom v.nh <ilinT 
;ii Hpiifaratir.', fur iii^t.-iiirtr oi t!;" ]ii:r»'oii nr of tin- 
'aliha,'!', i.- a ri-iiiarkaMo tact; nmn' ••-.jit»rially wln'ii 
Mort'lifi't how ui.iiiy -j.fij.-i tiifii' art', wlm-li, tlnniL'li 
rcsmililisitf <'a< li ftihcr inn-; rlosdy, art» iitl»'rly >.trr:It« 
v^lu'ii iiit('r«Ti>»-t'(l. >r\<Tal « (iii--iilir.'.tii>ii«;, li(iwi'\fr, 
rtiiilcr tlio tcrtility <»^ dumc-tic \ari<'ti<'< 1<— > ri'inaik- 
a:>U' lliaii at tir>t ajiiM-arx. It can, in tii(> lir-t j.Ia. i', Im» 

■ h-arlv -I'uvii that nicrt' rvtcrnal i!i--i!nilarity hctufcu 
\ M.> «|ii'ci(^> iluiw iiiif ili-tfrmini' t heir urcatrr or lf>—i'r 
iif._rri'c ot vtcriiity .Oirii cro^-rd ; aii'' vvc may apply llio 
■imc ruK' Id lioiiic-tif. Miiiitif^. In tlic x'lnud placf, 
-irtnc oniiin'ul iiai iirali->t.H hclitvt^ that a Imiir <<>iir<i' ot 

■ |lllll(<•^ti(•ati' II tfnd> to t'liiiiiiiat»' sterility in tiio suc- 
<'-»ive p(Mi«*ratii)ns of li\ hridn whirli wtrt' at fii>t (inly 

-I . htly st»Tilo ; and it this he h», wc Miridy niiL'ht not 
t(t rxpei't In find -tt-rility hnth appfarin^^ and di^- 
apj. raring under nearly the same ronditicms of lile. 
I.i-tlv, and tlii> .•.ceni^ to nie hy tar the n)o-t irnportam 
i.::-ideration, new race-i of animals and plants ar • pru- 
i'ued under duiiiestnation hy man's tnelliodieal and 
incons('iou:4 power of .■»election, tor his own use and 
;ileasure: he iieitiier wislies to select, nor roiiid .-(dfit . 
'liirlil ditferenees in the reproductive sy-tein, or otln-r 
' I'ustitutional ditVerences conelated wiih tlie repro- 
ductive system. He su|)plies hi- several \arietif- uitli 
the same t'oud ; treat." them in i^early tlie >ame numncr. 
ami does not wi.-h t<> alter theii ^''eneral iiahits ot" lite. 
Nature act- uniformly ami -lowly durinir ^"'"-t 
n riod-i of tiino on tlie wlude or^'anisation. \n any 
•:iy winch may he tor each creature's own irood ; 
md thus she may, either directly, or more prolialily 
lidirectly, throufrh correlation, modify the repro- 
•iuclive system ni tiie se\eral descendants ironi 
juy one species. Seeinir this difference in the pro- of selection, as airried on hy man «nd nature, 



Vkf in«-cl iHit !•< •iurpri-cfl al MUiif «liffercn<o in the 

i li ivc .iM y«'t ^imkrn ;i« it t)i»- \ .iriftii's of tlu» name 

H|.cfii'- Wire iiivarviMy fcrtili' wlicii nitrr<TH-.-»'(l. Mut 

it ^itiii" to nu- iiniMoi-^ilil*' to r»'»i'<t tin* rMil»Mue »i Ui« 

i>\i-ti'm o ot a <•<•:•. till ritiiutitit of >tiTility in tht* fVv* 

fnllciu 111;; f.-i^o*. \.!ii'li I «il! liri«'t!y :ili--tr.i<'t. 'I'lie 

t'\ idcriif i- at l«'a-t a« ir'""! '!•< that troin wliirh we 

licliinc III till- -tcr.lity of a miiltit mio ot sju'fii's. Hie 

»'\ ulrii.f i<, aUo, <itTi\iMi from li(i»tili> •< itiifsseH, wlio 

in all otlMT (^-ffs roiiMiifr t'rrlilily ;iii<l ^t^'rlllty ax safe 

tTitirinti* ot' sjrt'fitic ili-tinrtion. (i.irTnt'r kr\>\. <liirintt 

i-r\ \('ar>- a li^arl kiml of iiiai.'»« witli y ■.■>« set'd", 

au.i a tall sarii'ty with n'W •<«'«'«i>, utovmu:.' lu'ar ••ach 

otlitT in Ins i:,ir<i«'n ; iin<l ailiiontrli \\iv-i' |.lant> have 

f«'t»:i'-.ii.M| s(.\cs, tlif'v in>\ »'r naturally cro^si-il. He 

tl (Ml ttTtili-fd tliirtccn tiovviTS of tlit' on«» with the 

Ih.UiMi ot til.' otht-r; lint only a sin;.'lc h«>a(l jiroiliicetl 

:iiiv -ffil. ami this ont- hi-aii |>ro<liict'i| only ti\t> irrains. 

M.'iiiil.ulatMni in tin- r.i-c couhi not liavt- Immms iniiirious, 

a- t!ii' j>lint-i lia\t> M-jiiratrd >t\«'s. Nonn»', I holit've, 

Ills >.u»i><'«!ti| that tlii'-e varij'tif* of rnai/«' arc lii^tnu't 

-|M'(icN ; ami it i-* ini|iortant to notu-p that tlie hyhrid 

|'i:int«i thn^ rai-<''l wer.' thfin^'hi's j'rt'vtly fertile; «0 

'li:it CM'!! liirtner <liil not vpntiire to con-uliM the two 

var:i'!if< a> sprciticallv ili-^lun't. 

tiiroii lie Un/areiniTut's rro-.e(l tliree varieties ot 
^'Mird. whirh like 'lie ?!iai/e ha- -ejiarated >e\e><, aiui 
he :i— erts tli»'ir imitnal fertilivitioii i- hy so nnn'h 
the l.---; ea-v a their tlitriTeiu-es are irreater. How far 
•lie-e e--i>eniii<'nt- may he trnste.l. I know not ; hut the 
Inrni- exj^eriineiiti-eil on, are rinkeil hy Saj'.iret. who 
f.iinlv founds his elassitieatic.n hy thete-t ot infertility, 
it- \ Mri»»t les. 

riit> hd'ouini,'" <"a-e is far more reinarkahie, and 
^eeiMs at tir-t ijiite inrre'lilije ; hut it i- the result of 
an astniii-hiinr nuintier of exjie'-Hiient- made durifnf 
n::tn\ \ ears .m nine -|>eeies of \ erhasi-utn. hy so t'ood an 
oil. Tver and so ho-tile a witness as iiartner : namely, 
tiiat yellow and while varieties of the same sj)ecie« of 



1 w 

-*5» ■ «•< 


.■,.*. .;.'■-»•.., ^r---'>f-; 

:/>■«- r- 



\>rh»«rum whon i!,tprrr(>-*'*<»<l pnnluco li-— ^••«•ll, tli;iii 
do «Mtlitr nili'iired \ari«'ti»*H »li«*u fi-rtiiiM'il uiih j-oilfn 
frorii t)ipir owii ((iluiiri'tl iIohiT'*. M(ir<'t>vt'r, In* a-MTt.-i »}u'ii yf'ilow Hiiii wliite v:iri»*li«H or <»ii»> >i|i.Tif4 ;ire 
iri>-«m«<l will: Vfll'i* aiiii >»!:if»i vunttn'.i ^tt ;» tiJi'u,r, 
-i>«yit>«, more nee'l i- prinlur«'<i \>\ lli»« «Tov>.e« l>otwt'«>n 
!li«- sinul.irly ((dnurwi llowers, Ukui Ix'twivii tlio-e 
«Licli arf dirfiTtTitlv « oloircii. V»'t til**"*- v;iri«Mi»'". of 
\'t'rh;iRciirii jirfHi'iit iio otiit'r dirieri'iire l>«'>i.U"< tl.<» hut*' 
oUiur of tiie iliivrer ; ami one variety i-aii Mtnietimex be 
rii-t^i trorii t)ie Ht»eii ol the nther. 

t ro!ii (ili-ervatioiis wLnli I hixr niafi'- on certain 
..irietie« ot Imllvliofk, I am iiirlmed to >.,iv[,(.ct that 
■ffv nrceiit aiiali)i:oii'< ta', l^*. 

K Ireuter, who've iitviiraiv lias U««'ri iniifirined l»y 

.•»ery Mihse<jtieiil nhserver, iiic-i proved the reniarkahie 

fAit. that one variety ot the ((iiiinioii tohacro i>i more 

••r;ile, when crossed wilii a widely di~tinrt spe^ leM, 

M.;:. are the otlier varieties. He experimetiti>.ed <m 

>e inrm-i, whii li are eommouly repiile<l to he vanelij-x, 

. d wliifli lie te-ted by the severe-l n.imely. b\ 

.f.iprdrai crosses, and he found their montrrtd ori-prina 

.-rtei'liy fertile. Hut one of" the^e five varieties, when 

-ed either ax father or mother, and iTo«?>ed with th^ 

N 'otiana trhitinosa, always yielded hybrids not ■»') 

t'.sie a-s tho»e whieh H<'re produeetl tmiri the four 

I tr varieties when cross*^! with N. iriutuio^i. Hence 

!• roproduetiNO svtem of ihis one variety rnu-it have 

' (■( 11 in some manner and m nome deirree modilied. 

Irom these fai'ts ; from the ifreat diiHeuity of aerer 

i.'iiiiu' the infertility ot varieties in a state of natun'. 

. 'f a sujiposed variety if infertile in any decree would 

. ■•'.erally bo ranked as 8j)oeies ; from man seUn'tinj; 

■.!v external eharacters in the produitioti oi tne mo>t 

iHtinct domestir varieties, and from not wi^hinj; or 

•1 '.i'j: able to produce recondite and functiftnal dirfer- 

piif-es in the reprttdiictive system ; from the-.e several 

coiiMiierations and facts, I do not think tiiat the very 

ijeneral fertility of varieties <an l>e proved to be of uni- 

vf r-ia! orcurrenci^, or to form a fundamental distinction 

~;i - . ^m. a 

■ ivr-.-vV' 

/^. .,:'. ','--> - 




bctwpoii v.irif'fic-: ;iti(i -{)0<-i»'<. Vhc ircn^ral fertility of 
varieties dni'< not -criii to me <iiniiit'nt to overthrow 
tlic \ic\v uliirli 1 liii.e taki'ri uitii n'-|toct to t)ie very 
pr'ni'r.-il. h':\ no' in\■.•u•i:l^'<•, wtcrilify of iirst cro-^op aud 
ot iiyltri(i>. n.iiMi'!'.-. it i> not i -j>"cial emiowment. 
Imt K iiir'il."i'.il on -low Iv nc-jiiircl iiioilil'.c:itioi:<. nutre 
i'-j)Of';il!v i'l '.•it' rt'jirotliictive sy-teins of the fornriB 
which art" eio-- cl. 

Ihi'irids fill'! M<!)i'irr's rninpured. rn'/ri.fji'lrtif/i/ of Ihnr 
/i-WiVi/f/.-- I idi'i'.MulfMitly of 'he ■|';p.t;nn of ftMi'lity, 
the otf-pri'L' of ^irt'cie- when crc-J-fi rnni of varieties 
wlieri cro'-^'l !ii:i\ ite fotiinire'l in <overal n'Ji.'r r<'-jM>cts. 
(i irtntT. «ho>-e -troiitf wi-ii wa-i to draw a niarkc I line 
of (ii-^tinctinn Kotween »jiecle- and \ar:etie-, conhi find 
verv ftnv atid, ;)•< i* seems to me. .iuite iiniriiportaiit 
diJierences hetwt'en the -o-calh-i hytirid nlf^prin!; of 
8](ecies. and tlic -o-calh-d nu'iiuTcl orfsprm^- of variftieu 
And, on ti.i' other liand. th(>y airree most closely in 
\ery many resjiocts. 

Ishall here diM-iiss this suhiect 'vith extreme hrevity. 
Hie mo>t nn]>ortant distinction is, that in the rtfHt 
^'cneratioii moti^i-nds are more variahle than hyhrids ; 
hut (JiTlner admits that fiyhrids from -ipecies '.vhioh 
have |i-n._r heeii i-iiltivated are often variahle in the first 
generation : and 1 have myself seen strikidL' in^-tancofe 
of t]ii« tact (lartner fiirtlier admits that hyiirids be- 
tween \er\ (losfly allied species are more variahle 
thin tho-i' from v'erv di-^ti net species; and thi- -liow? 
that the ditfereni-e m the di-irree of variahiiity irrailnate^ 
avav. \\ hen nionu:rcls and the more fertile liyt>rid>< 
are j>ron.i:raled for several trener:;'i<.ns a!i extrenie 
anioiii.t 'of variahiiity in their o'-prMiir is notorious; 
hut some f»-w ca-^s hoth of hyitr.d;-* uid moiiLTcls hinjr 
retainiiitr nniformitv of chara .ter could be j-iven. I he 
variahiiity, houe\er. in the successive jrcnt^ratiouH of 
mniiirrids i>, iierhaps. L'reater than in h;''ridn. 

This L''reat('r variatulitv of monirreis ttian of hybrids 
doi's not socm to me at all snrprisiiiir. For the parent* 
of inontfrels are varieties, and mostly domestic varieties 





fvory few exi)erimeiits haviiitr h»MMi trio<l on imtural 
vari<;ies), aii<l tliis iini>lies in nuxx ca>es that tliore has 
■jvt'u rcieul vf.rial.ility : aii<l thrrefore we ini-ht t«xi)ect 
• >uch varKil.ililv wouUl (tftcii .oiitiiiue and l'«' 
ad'lt'd to that arisiiiir from tlie nier.- art ot rn.^in:,'. 
Iho ^litrlit (Icirrt'f of variahilily in liyliriils from the 
hr^t croos or in the lir>t ^rt'in'ration. m contract with 
heir extreme varialjilit\ in the .-.ufcee<lintr ueiieration>, 
IS a ttirioiis fact and deserves attention. I or it hearv 
,>n antl corrohorate.-* tlie view vkhirh I liave taken on 
'in- rauKP of ordinary variability ; namely, it is due 
to the reproductive' sy>tein heintr eminently -ensitive 
u) a;i\ chanire in the .onditions of life, t^eintr thuH 
itteii rendered either impotent or at least inrajtahle 
of ax proper famtion of produrinir otf-prinir identical 
With tlie parent-form. Now hybrids in the tin-t treneni- 
lioii are deseendtd from >pei ies (excludinjj tho-e lont' 
,ult;\ate<l) which haxe not had their reproductive 
-v-teins i an\ wav atfectcd, and they ar. .t variable ; 
i.ut hybrids tbem>elve- iiave their reproductive syst»-ms 
-.riou-Iy affected, and tiieir descendants are hiijl 

I'.ut to return to our comparison of moiiL'-rels and 
•lybrids: (i.irtncr states that motiirrels are more liable 
♦ I' hvlirids to revert to either parent-form ; but this, 
I it be true, is certainly only a ditiVrence in detrree. 
•tn.T further in>i-.t.> ' that' when any tu.' species. 
; iK.Ui; i most closely allied to each otiier. arc cros-^ed 
vvi 1. .1 third spcies,' the hybrids are wi.iely different 
•i..t.i each »»thcr; whereas if two very distinct varieties 
■ ,i one s|KK'ies are crossed with anotlier species, the 
(,ybrids do not dirfer nnich. liut this conclusion, a*« 
r-ir liA I can make out, is founded on a sin^rle e\i)en- 
II. cut ; ind >eem8 directly opjtosed to the results of 
rr^enil experiments maiie by K.'lreuter. 

11, .-e alone are the unimportant ditference*, which 
tJ.irtiicr is able to point mit, i'etwt'en hybrid and 

rJn»iiurt5i piriiilS, XfH i»*C Ui::tr: iirttt-t^ - 

in iiioiijirels and in hybrids to their respective parenU, 
more eH.,ec-ially ui hybrids produced from nearly related 




ON Uli; (U{I(;iN OF SI'E( IKS 

'V u 



snccio-;, f<ll()w rKijor'lmy to (iartupr tl'«* ^rlme laTP. 
\\'lion two -iixMii's nrf cro^sod. oiu' ^ornotimet 
a prt')i()tiMit ji(iw«»r of imjirf'ssinir its l'kciu'>>-' on 'hi^ 
hviniil ; .iii'i 'io f lu'l^nc it to he wiili \ariefie^ "i 
plaiit-i. V\'itli anirn.'iU oiio \:ir c' y ctTtaiDlv ofVn ha- 
tlii- |ire5K»ttMit j>owtr mer HiMi'lier \.iri<'tv. Uvhr^'l 
{ilaiT'^ |>r<'ilijff>il troni a rociprocal .•r(i<;s, e'lHTally re- 
soinliU' JTirh other clu-clv ; arjii so ;t i-^ with moiitrrols 
from a ri'i-ijirM/al crixs. Motli Jiv'iriiiw ami nuHiLTt'ls 
r^'iii he rodiHCfi to jmiIht {mitp |>arf;it fnrrn, hv rcjicatfd 
cro->»'-! in s\l'•^r>s^ive trt'urratioiis witli rithrr pnrtTit. 

I li»"i»' sc IT il remarks are ajipareullv api'liiahle to 
aiiiiii il» ; t)i;t ttie sul>jpet is liere excessiveiv ronnili- 
cato'l. partl\- owMii^ to tlie exixtence f)f ficcotidarv "seiiia] 
oliarai'ttTs ; Imt iimre especiallv owiiijr to prepot^noT 
ill traii-niittiiiL'" likeness ruiinirijr more ftroiigly in onf» 
sex tiiaii III tiie oMier, liotli wlieii one species is rroHsod 
with mother, and when one variety is missed with 
another variety For instiiieo, I th'nk those author? 
are ritrlit. '*h<i r.iaintain that the ass )ias a prepotent 
power over the horse, so that tioth tlie mule and tiie 
iiiiiny more reseniMe the ts'j than the }ior>^e ; hut that 
the prepoteiu • run-> more stroni:lv in the ma! than 
in the female, so t}iat the mule, which is the oifspriujf 
of the male-ass and mare, is more like an ass, than is 
the hiiinv, which is the otl^prinir of the feniale-as« and 

Much stress has l>een laid hv some authors on the 
Bup!)os«-d fact, that monirrel an:nials almie are !>orn 
cl(i-''ly like one of thoir parents ; hut it <a:i he sliown 
that tliis does sometimes occur vvith livhrids ; yet I 
(rrant niucli les.s freqiiently with hylirids tlian with 
motiirrels. l/ooking: to the cases which I have colle<'ted 
of cross-lired animals clo-eiv resemhliiiir one |>arent, 
the re-^ernhlanctv seetn cliiefiy confined to cliaractera 
almost monstrous in their nature, and which Lav© 
fiudti'Mily appeared -such as aliiinisim, melanism. d#- 
noie.u V or u<ii oi iiorns, ot iildiuoUai ruit;ers .tuu Iajc* , 
ami do not relate to cliaracters which have heen sjowlr 
acquired by selection. ( on^djueutly, sudden reversioui 




U» the i»erfort chanu-ler of pitiuT parent would Ik, more 
hkelvtoofcurwithmoi.irreU.winrh ar.« .l.'M-etHle.l f:..m 
varieties ..tleu .-u.i.l.-nlv |.rn,»«.i an.l ..-MU-inoi ^inms 
m ,-hararter, tha>. wtl. LyLrwis whi.h arr .i-Myn.UMl 
Torn M.i'.-i.'s .U.wlvainl nalunilh i-rodio nl. On ne 
.hole I t-nf.r.-iv aur.'o wuh Dr I'm^p.-r Lii.a.>, «!m. 
,:t.^r arranuinir an oiiorm..u- l.."ly ot i.i.-Ln with r.-^i-ort 
U» animaU, ronH-s t.. 'i.e^n.n. tl.o law, of 
...,wnhlano. of tl.., rlul.l to .U par.-nts are t ,.• s.n..-. 
wlu-Uier thf two ,> .li.f.T nuul. or little tron. 
,vi.-li oth.^r. nauH'lv in ll:.^ •mion of .u.livi.lua.s nt ti.e 
,.ime varu'ty, or of .liih-n-ni uirieUes, or oi .l,>lin.t 

■ipei-ies. . . ,. , •'■,,.;,, 

UvinL- a>i.le ll.e .,ne^tioM of fertility a-ul . .TMitv in 
.11 other re.-neob, there >ee.n- to he a u.-.o-ral a...! .•■.-.• 
Htmilaritv in ll>« otrsprin.- of .to,..-.! -i-r.-.e,. .uul -t 
cro^Mxi varieties. If we look at sj-eeies as h.ivin- ..-en 
.penally rreate.l. an.l al a. hav.njr he.-, 
urodured hv ^>con.larv iaws,thi> -iinilaniy «oiihl he an 
a^toni^hin-'faet. liut il hanooni.-es perle.lly wun the 
view that t h.-re is uo esseuliai .iisUncUon between speeies 

ami varieties. 

>./mm./rv of ('hapt^r.-Vu.. .rosses lK.twe.-n forms 
.uth-ienllv diVtin.-t to he ranked !i.s .pecies;uid their 
hvhnds, are very ^'enerally, hut not univers.iilv, ^tenle 
Ihe sterility is of all dej-rees, and is otten s<. s.i-lit thai 
'ie two most .arelul experi.nent;ili>ts who have ev.T 
!i\ed. have .••»Tne to diameiri.:ally opposite oonrlusions 
m rankiutf forms hv this test. Tlie .tenl.ty is nwiatelv 
vari.ihle m individ'uals of the same specu^*, and h 
.■miiientlv «u>.M-ptilde of favourahle and untavoiirao e 

oM.iitions. llie de-ree of sterility doe> not str.-tly 
i.uh.w systematic athnity, hut is governed hv sev.-ral 

•.nnu. and laws. It U generally ditferent, 
«u<l ^ometime9 widelv different, in! rnw>es 

■ervveen the -.ime two specie.^. It is nut ulways eyial 

. 1 :.. .. i^y^t rro^- and in the hvhrid itrtxlu. I'fl 

trotn tlii> iTo«-.. 

In the ~ame manner a« in ijraitnitf trees, the capacity 





Is' i 





13 f 

-- g- 

; : ^J-. 




oMiiie sjX'cu's f»r variety to take on .inothor, is iru idpiital 
on jrtMicrally iiiikii'iwii (litftTciices in their vt'L-^etative 
HV^tfrii-, M) iti (•r()--iii::, the {.'reaternr h'ss tai'ility of one 
s|>ecii>>. to unite « itii aiiiitli.-r, i^ iriciileiital on iinkiit)wu 
di(f('rein-e>i in tlieir reprudm-tive .-Nvteins. I'here is no 
tiHire re.isdii to tliiiik tliiit ~[iecie-. h.ivo heen siiecialh' 
endoue'l with \arii>'i> ile_Mi'c, of .-tcrility to jireveut 
thern cnt--iii:r ami lih-mliiiLr in nature, than to think trees heen specially emlowefl uitii various and 
H<iiiie«hat atialoL'-ous de^rrees of ditriiiilty in beintj 
^rraitfd lo-ether iii order Ut prevent them beeoniini.' 
inarched in our foie-is. 

'I he -tcrility of iir-t ero>>-es hetvveen [«ure species, 
which lia\i' their re|ii(»diicti\e sv>tein- pfffect, seems 
to dfj.ciid ou circum-tance- ; in some cases 
lai-L'-ely on the early deatli of tlie enihryo. 'I'hc -terility 
of l;vl)riils. which ha\e their reproductive system's 
impt ifect, and whi.h ha\e tliis system and their 
uliulc or;;-a!ii>atit.n disturbed hy hein^; eompoundeti of 
twi>di>tiiict >pecie«., seems cio>eIy allied to th.t sterility 
which so freijuently affects pure sjK'cie-:, when their 
natural eoniiitious of li;i' ha\e heen di-turhcd. This 
vic.v i-; '^uj. ported hy a paralleli-m of another kinrl ; — 
nauiely, 'hat the cro-isirijj of foriiK only sli^/litly ditlerent 
i- ta\ oiirahle tf) the viiTour r.nd fertility of their offsj>ring ; 
and that sliirht eliaiiires in tin; cotiditioiis of life are 
apparently favonra'de to tiie vit'onr and fertility o." all 
orL^uiic heiiiirs. It is not siir{>ri>injr that th? decree of 
ditliculty in unilinar two specie-^, and the <lejfree of 
sterility of their hyhrid - otrs])rinff should jjeiierall 
CO re-i|MHid, thn i;r|i (l,j,> to di-tnu^t causes; for b 
dcpciid (HI the amount of dilferenco of some kiud 
i>-lweeii the -pecles which are cro-.-ed. Nor is it 
surprisinT that the facility of effectinir a first cross, 
the fertility of the hJ.rids produced from it, and the 
• apacity of hein<»- trratted tojrether— thouirh this Utter 
CHjiacity evidently depends on widely different circiim- 
si.uices -^should all run, to a certain extent, parallel 
with the systematic atKnity of the forms which are 
subjected to experiment ; for systematic affinit? 




„ttempti* to expn-vs all kiiid^ of resemMance »«tween 

.-xll species. . 

Kir^t .•ro-J^*'? heUi-on tormn Known to he varieties, or 

••utRnentlv filik(> to i.e coii>'iK're<l as xarie^ lo-. and their 

m.iitrrel otNprinc, are verv eonerallv. l.ut not quite 

;nvi-r-;.;lv. tertile. Nor i8 this .i,>;.r!> trnioral and 

i.rrfect frtilitv surprisini;, '^hi-n we remfinher huw 

1. il.le we ar« to'ar-ue in a oinle with rospe.t to varieties 

-, -i etate of nature ; ami when we tliat the 

reater numher of vari.'ties haxe hci-n produ.e.i under 
'on.estication hv the selec n of mere external ditfer- 
, Mies and ii. t oVdirterenc in the reproductive system. 
m ail" other respe»-ts, excludinjr fertility, therein a doH« 
■ M-neral reseml)lanr.' hetueeu hyhrids lind moni^rels. 
K iiallv then, the hriedv tfiven in this chapter do 
rn. ^ei-tn lo me opposed to, hut evu rather to ^upport 
t!.^ Mew, that there i» no <-undamenUl d^stii.a on 
•,v -weeu species and var'.fties. 


fM i 


( HAl'l KR IX 


' n thf> »i««''i( (• ■.( !iit/'rni'>(ii»t«' vnriptiis itt th*" [>rf'<Tit ilay— On th6 
in»Hii<- ■'• eitiin I uiuriiKiiKit* varirtioi ; in their tiuii.l'tr tni 
Ihi' viiAt la;**" of tiiiic. a» i!ift'rri<l fr iii tin- rit« f .ir;..";ti n 
•ii<l of 'icuiihitlon -'In t!ir ["'"'■'i''*' '' ' "r jial i'<.nt< 1 /i <0 
C!!le<Uoii8 (»ii thn liitoriMlteii' e ■{ Kivpl.^ifal (■•r'natlnn - 
On tlif iti'ti',. o f lilt'-: mt'Iki'.'' \ariitiei in any >n- f rv.n:; n - 
On tfio »ii i kii kpi-fariii •• of cr ■'.;■* 1 »\ •■■i>^ - • 't} ihdi tnlleo 
ni»(»-i4ran>i- in I'.e lowest known fo-,sili(erout ^tr»U. 

Ivthi' s'\t ii rliaptor I eiiumf rated thi' cliiff ohiectionf" 
*»)iirli III!, ht 1)0 jti'^tlv ure»'<i .liriiusi il>e views niaitJ- 
taiix'd ill lliw vdhi'iie. Most of" tlit-m have now Uccn 
iliscii>--0(i. < >np, iianielv t!:t« distiin'tiu'Sfi of s|»«Mit"ic 
tornis. and tliiMr not ln'iiu? Iilpiid«>d t<»Lr<'ther '>y in- 
niiniHr.ildi' transitional links, is a v»»ry olivious diriinillv. 
! a^-'.'!ifd ri'asuiis why -.iicli links do not ronjiiionlv 
oi 1 ur it tln> present day, under tiie circurnsUtncfts 
.1' jiarently most tavoiirahio for tiieir [ireserit-e, namely 
on an •'xteM>-ivi> and oontinuous are^i with irraiiiiaied 
nhysi.a! conditions. I endeavoured to nhow, that the 
life ot" caeli species depends in a more important manner 
ftn the pre^eisre of other alre:uiv derine<i ortrnnic torn's, 
than on I'limate ; and, tlierefore, the reallv 
iro\erniMr condit'ons of life do not trraduate away <iiiit4< 
in-ensihlv like heat or moisture. 1 endeavoured, .ilso, 
to siioi* that inti^rniediate \ar;etieB, frt>!n exislinir m 
!es>er nnn;!iers than tlie forms wh'cli the) I'onnei'l, vmU 
frenerally he Ixjaten out and evterminated during the 


course of turtlier modification and iinprovemont. I'be 
main cau^c, ho*.>.er, of innumerahle uitiTim-diaUs links 
n,.t now .M-carnniT evervwlu're tlirontil,niit n-itura 
d.*poiid^nti til.' vervpnM-osHof.jitural sclei-.!oi.,throui'h 
whirh new %anetie,«. iMuitiiiually uk*^ the places ot and 
Pxtermmate their parent turms. Hut lu^t m proportion 
a., thif» process ot" extermination has a.ted on an 
f^nornious <r ile. so must the nuinher of intermediate 
varieties have formerly existed on the earth, 
Ke trulv enormous. Whv then is not every ffeo- 
lo.' tnrmation and every stratum hill of ^ueh int^'r- 
mrdiate l.nks ? (ieolojry assuredlv does not rovea any 
^url. hnelvtrraduated orcanic rhain ; an.i tins jrt?rhaps, 
w the mo-it obvious and ^rave-sl ohjecti<.n which .an V* 
.;r..ed a;:ain<t mv theory. Hie explanation he-, as 
»„.lievo, in the extreme imi)erfection ot the Keolojfical 

'^Vn" iie first pl.-^ce it should always be tK>nie n mind 
wh;»t sort of intermeiiiate forms must, on my thecir), 
base formerly existed. I have found it d:fT:cult. when 
lo..kine at any two species, to avoid picturintr to myself 
forms ,/,r^-fVintermediate l>etween them. But this is 
a wboUv false view ; we should always look for form- 
intermediate between each species and a common but 
ui. known prourenitor ; and the proirniutor wilU-eneraUy 
have differed in some rosi)ect.s from all it.s m..d!tieri 
'le^rendmt.',. To trive a simple illustration : the tanUiil 
iiMi pouter pi>?eonshave both de««:ended from the roi-k- 
pieeon ; if we iH)sKessed all the u termediate Tarietie. 
wlM.b Irivo ever existed, we should have an extremely 
close heries between botli and the ro<-k-piiroon ; but w». 
^houlH have no varieti.M directly intermediate Wtween 
the fautail and pouter ; none, for instance, cornbinmir 
* tail somewhat expande<i with a crop somewhat en- 
l;ir-.'d. the characteristic features of these two t.reesi*^ 
Ih.'«;e two breeds, moreover, have become so murh 
moditied, that if we had no historical or indirect 

.1 J » I.-. 

VO ri^^^n 

e\ i<it'nce rc..';iriiiini Uieir ruig^n, "•>. 

possible to have de^'rinined from a mere comp 

their .tructure with that of the ruuk-pirfeou, wheUier 


II of 





they had ilescended Irom t)iis aperies or frtini rtome 
other ;illii'(l sjiccio-i, such as ( . oeiias. 

.So with natural s|ip( ics, if we htok tu turtris very 
diHtiiiit, for iiistatice to tliW h<ir-«» and t.ijiir. we have 
no reaxin to «-up|in-f that links I'vcr ('xi>t('(l directly 
iiiti-rnu'diate ln't««.'tMi thfin, hut hi-tv*(>»'ii each ami an 
Liikiiuvvn romnicn |>arcnt. Tho coninion parent \»ill 
have lia<l in its wliole oriranisation hmk h ceneral rosem- 
hiiincf to the tajiir and to th»' hoi-c ; hut in >>orne 

IMnnt> (>i struitiire may ha\»" diihrtMl con-^idfrahly from 
lolh, even perhajis more than they differ from eaeh 
other. iieiice in all Mjih rases, we should he uiialile 
to recognise the parent -Ibrm of any two or more 
t'pecie-i, e\en if we closely compare*! the ^tru^•tli^e of 
the parent with that of its nioditie<l descendants, unle,ss 
at the same time we had a nearly perfect chain of the 
intermediate links. 

If is just po<sihlo hy my theory, that one of two 
llviiiff forms m::,'ht have <lescended from the other; for 
instance, a horse from a tapir; and in this ca>e(/*r'C< 
interme<liate links will ha\e existed hetvs oen them, 
hut pucli a case would imply that one form hail re- 
tuained for a very Ion:; period unaltered, whilst its 
descend. int> had undergone a vast amount of change ; 
and the principle of competition hetween oiiranism and 
orL''t ween child and parent, will render this a very 
rare e\ent ; for in all cases ihe new and improved forms 
of life tend to supplant the old and unimprove«l forum. 

IJy the theorv of natural selection all iivinif species 
have heen connected with the parent-specu-s of each 
l^enus, hy ditferences not trreater than wo see hetween 
the varieties of the same species at tho present day ; 
and parent-species, now jrenerally extinct, ha^ i 
in their turn In'en similarly connected with more 
ancient species ; and t,o on hackwards, always con- 
verj{in^ to the common ancestor of each preat class. 
So that the numher of intermediate and transitional 
links, i>etween all iiviutf and e.xt ' t species, must have 
been iuconceivahly g'reat But assuredly, if tins theory 
be true, such have lived upon thiH earth. 


on tht i>ir"<'' "'" Timr. - lutlepoiKl'Mitly of our not 
finrliiiir fossil remains of ku. I. iiUiiritrly luimornus con- 
n.Ttii.ff lif)L-, it inav he ol.iorto.l. timr will nut 
h,-,vn snffi.T.l furs.. ^'^fAt rin amount nt ..r-:ii!K .h.-uitre, 
■^\] .•h:u,u^o< l:;ivin- U-en ..ifrrtcl vorv «ln<x ly tlir..M,rh 
■ •ituril <el<N'tiun. It is l.vnily i-o.-.'-lo lor me »-y-n to 
ro.all ro the r.'iL'r. who may not l.e a prartn al iroo- 
io-ist tl.p ta.t. lea.iinir the mmd to .-..mprMuMid 
,!,; lai.-o ot time. Ht> vrho ran r.-a-l >ir l I, irlej, 
I v.-ir^ --raJid work <»ii th.' I'nvrifUrs oj i^>, wlii-li 
tl M future ].i-t..rian will rocoirni^.- as havmir pro.luc'd 
a rrvnlutioii in natural M-ienre. vet «loos not a-lmit how 
-,...mnrelMMi-iv,.|v vast h.v.H' h.-en the ,.a.t j.-r.-vls of 
Mine, niav at nn.p cIom- this volume. Not tuat it 
,•,, Hires to .=tu.h' t1... I'rinnjdrs of ^VoA.vv. '«r to re;%i 
M.<"ial treatisrs hv different ohservers ..n M>i.araTe 
formations, atul to mark how each author atfrnp's to 
L- X.- an iua.lequate idea of the .luration of earh Jorma- 
. ..,, or oven each stratum. A man mu>t for yean 
..tamMie for himself trreat piles of .ui...nmi.osed strata, 
and watrh the s.-a at work trrin'imjr 'h>«n old rocks 
and makintr fre-h pediment, hefore hr .-an hope to 
rn-nprehond anythint? of the lapse of time, the monu- 
iii»'n»< of vihivh we see around us. 

It IS lmxmI to wander aloiitr lines of ^ea-coast, when 
tnrmed of moderatelv hard n.rks, and mark the pro.-ess 
..f degradation. 1 he tides in most case's rea.h the 
, liT. onlv for a short time twiee a day, nnd the wavea 
.•at int.. tlH-m onlv when they are .-harired with «ai..i -r 
nei.hle^; for there is c().)d evidence that pure water 
. ui effpct little or nothinsj in wearinff awav r.ick. At 
la^» the ha-^i> .>f the rlitf is undermined, lui-.- tr.Oirments 
Jail down, iv.d the.e remainii'L- H.xed, ha^e lo he worn 
auHv, atom hv atom, until redu.'ed m si/.e tuey i:an l« 
r. It.Mi ahout i.v tlie waves, an<l then are more <;..Mkly 
irruund into pehble.^ sand, or mud. lint Ih.w ot>.«>«i ^o 
we .P<. al..nir the hases of retrcatintr clttfs rounded 

, , . 11 .1 ■ t 1.. .1 t I, ^.1 r>\'krir)o Tin )(t t iri tt II 11 . 

tnni ti 

u.«'ho-.v little the\ re abraded and how seldom 

they are rolled about ! .Moreover, if we follow for i 





U'w m\]o» any lino of rot ky clitF, wliicli is undoreoinn 
«lfirr.i.l;iti()ii. wt- fi, I tli;it ii iHonly li«'re;iti.l tlitTo, alorijf 
a hhnrt h-imtJi ..r roijii.l a firnrnoritorv. tlif» rlirfH 
are at tJu* pn-^jMit tum' •.utfcniiif. 'Ili«' aj>ii«'ar;uicp ol 
th(( ,surf.i(t» iiiiil the \r{r»'t.4tiiiii h1io\«' tliul eUowliere«, ii.ivd «'l.i|isO(l siiiro tJi« "iitrr^ v».im1um| tlicir base. 
Hf i«lio tii(»t • l<>-.«»ly studies* thf action of the nea on 
Our sliores. will, I i.clicv««, !.«« tuont (icepis impresHftd 
with the Rlt^wni's.- v»iili which nx'ky co.i^tM ;irp worn 
away. I he oh^iTvatioiiH «)n thin head h\ llnch Miller, 
nutl hy that excellent ohserver Mr. >r' itli of .foniaii 
Mill, are nm-t ini|.re'.>*ive. With th* iniiui tlius im- 
pressed, let any one evitnine l)eils of conirloiiierate 
man\ thoiisaiid /eet in thic kne>s, which, thouirh prol>- 
ahly funned at a <|iiicher rate than nianv other 
deposits, yet, Iroin hciiiir formed of worn and rounded 
pehhles, each td wiiich lK»^rs the titaiiip oi time, are 
ffood to kIiow how Miowly the ina.s> lia.s l.een accumu- 
lated. In t)ie ( ordillora 1 estimated otu- pile of con- 
jrlomerate at ten thousand feel in thickne>Js. I^et the 
ohi>erver reiiiemher l.yelJH profound remark lliat the 
thickness and extent of Kedimeiitary formations are the 
re.sult and me.-mure of tlie dejjradation which the ear! ' 
crusl ha?, elsewhere suffered. .\ud wliat an amouuc 
of de^'railation i« implied hy the HedimenLarv deposits 
of many countries [ iVo:es.sor Kams;iy ha." jri^en me 
tiie maximum thickness, in most cases from actual 
r.ieasurement, in a few oa-se? from estimate, of each 
loruiaiion in difierent parLn of (iroat Britain ; and this 
is the result : — 

I',il.T.'7..u' etrafa (not liKimiliiK iSTi(^)Ui l)«l»i 
Tertiary slriifH ... 

57, IM 

— makintr altoirether 72,.'>B4 feet ; that is. very nearly 
thirteen and tiiree-cjuarters Hritisli miles. Some of 
the formations, which are repre.sent©d in Knji-Iaud hy 
tinn he«ls, are thousands of feet in Ihicknes.s on the 
Continent. .Moreover, between ea<h succes.-.ive forma- 
tion, we have, in the opinion of most ideologist*, 

IMl'KKFKCnON OF CEOlAHiii Al, HF.( OKI) 255 

eiii.rriii»ti>U l<"iU W.aiik jioriotU. ."^o t'.ai thf Icttj pile 
lit s.'.lnnfiitarv ^>(•k^ :ti linlain. (fives l.iitaii ni.i<i«>ijii;i«e 
Hiea «if th<> titiu- wlixh /i.-w ela[.'«-il ilunni.' tia-ir 
a. ;«>ri ; \ f»t wiial liiin- liiH iiiu-^L h.l\»' fixis.jint'il ! 
(•otxl oli'.«'rv«T>i lla^ P e«itiniale<l t)iat MMliiiu'iit i*- il»*- 
|.o-.te<i h\ th»« ^rrt-at Mississippi rivt-r at tlit« ratr nf 
oiilv »;iK" tfft ill H liiiiulrt'ii tln>us;ui<l jimfh. I hi'* 
I'.stitnale lia" no prt'teiisioii to strul fxa<-t(.i's« : yet. 
ttiii'i.itriiit: nviTwJiit widr spart's very niu« sfilimeiit 
in triiiisporlnl by the «iirreiiU of tlu> sea. the prm-oss 
ot affumulaMiiii' lU a!i> <iiif area mist l-e .Mrt-niely 

lint tVf nnioiitit ot (iemi(iati()ii wh r)i tht* stru.i have 
III mail) |.l;t«fs surfori-il. v (if the r. :«• of 
u-cuinulatioii ot tiii- deirratled matlrr, proialdv ottVr.. 
tilt' l>est evidmre ot tlio lapse ot tiiii" 1 reh.cmher 
• i\inj/ lieeti iniali htruck witli the es iiietict ot lieiit.ia 
.,<.ii, wii»n \ .fwiatr volcanic islamis, which have hefii 
worn hy the waves and part'd ail r....iui into per- 
] .•ndicular clitis nf one or iwt. thousand left in heiu'ht : 
■"T the treiitle h1oj»© of the iavastreanis, d .e lo tln-ir 
: Tinerly liquid sute, showed at a »rlanre how i..r the 
hirii, rocky l>pd.« had once e.xtomipd into the (M>eti ocean. 
The name story is still more {diinilv told h\ faults. - 
•iio-.e trreat cn'icks alonjr v^hich the strata have In-en 
,.l,iiea\ed on one siile. or llirown tiown on the '.th^r, to 
!i. tieitjht or depth of thousands of feet : for r-mce tlie 
ri-t cracked, the Burface of the land ha- heen so 
,.ui plcttdy planed down \>\ the aiaion ot tlie sea. that 
no trace of these dislocations i" externally visihle. 
I lie (raven tault. for in>tariie. extends for upward;- 
of :•■>) miles, and alontr this line the vertical di»pl.ace- 
rneiit of the stratji han varied from <;»><• to .'Khm* feel. 
I'rnt. Ramsay ha- puhlished an account of a downthrow 
.11 Aiit'leseaof 2;>iM) feet; and he inform^ me that he 
.liv indieves there is one in Merionettishire of 12. '^K) 
r^i'X : yet ni tiiese cases there is nothintr on the suruce 
lo sliow sucii prodiifiouH nuivrmeiiLs, ihe piie of ro. «.« 
■i the one or other side havnisr heen sm<K)thlv f^wept 
4w«v. 1 he cousideraliou of these fat-ta impre-^e*- my 


ON I UK ()KI(;iN OF srK( lES 


mijid alinoHt in thr» sanip ni.iiinor ii>* •loJ's tli** vain 
(MMlfvivmir til i_T.i]>|ilt> with the hlfi iif ctrniity. 

1 am t.i .['tfi! to irivc ohm 'lilirr i a-c, tin- w<ll known 
one (il ili<« (l";i>ii!at;i(ii ot lim W CiM. I linii.:li il must 
'>o ;iMm;!t«'>l that tin- rlriiiKl.ilioii <.; th<> \\ i-al<l lia-< Loon 
!i iinTc tri Ic, ill ciimiiari-im v*iti! that wliirli han 
r«'!ii(i\('(l iii:i>-.r- ot inir j.aia'rt/iiii -tiita. in |>art>* t»'n 
thoii>.\ti(l tocl in thiikiif-^. a* >-hcnvii iii I'rof. I>am-av> 
nla^t<•^l\ in»'moir 0:1 tin- -ut.M'ct : ye' it is an admir- 
ahlo I. ■ i.n til «taii'i un tlii> iiitcrmfilia'c liiliy j'ountry 
an<l InciK iiti tlic <Mic hand at tho Nortli howns, and 
on th«' fit her hmd at. 1 h(> ><iii(h Dowrix; tor, rciiiom- 
h«'ri!i:r thai at 110 irn'at di«.t inco to tlif ^vi'»t the 
northern and soullicrn esrar|imi'nlj< moi't and « lo>i«*, one 
can >at.'lv jiictiire to oaesolt the irrcat dome of rocke 
wliich iiiij'l hi\o covered up Mie W i-ahl within bo 
limited a |»erind as sinre tli« latter part of the ( lialk 
lnrmati<'i\. Tho di'.tancp from the northern to tlie 
>oiitlicrn I >nnns i~ ahont 2:2 ::::les, and the tliickness 
of the s»'veial formations is on an average ahout lli>» 
feet, as I am informed hy Prot. llamsay. Mut if, as 
potno ireohit^ists siippo-e, a ran^'e ot c)hier rocks lunler- 
lies the Weald, on the flanks of which the overlyini: 
sedimentary deposits miifht have accumulate'! in thin- vr 
n\asses than elsewhere, the ahove c>timate would he 
erroneous ; hut this source of doultt probahly y:,<nld 
Tiot irreatlv atTect thfl estimate as applied to tlie western 
oxtrcmity'of the district. If, then, we knew tho rate 
at vWiich liu- --ea commonly wears away a line of clitf of 
any gWi^u hoi^'Jit, we coiihi mcisiire the time requisrite 
to have denuded the \\'eald. This, of courso, cannot 
he done ; hut we may, in order to form some cru<ie 
notion on tlie snl'ject, assume that the sea would 
into cliiFs :»(,«) feel in heiirlit at the rat<> of one inch 
in a renturv. 1 liis will at first appear much small 
an allowance: but it is the s;ime a^ if we were to 
assume a clitf one varii in nemlit to he eaten hack 
alouL' a w hole line of c(»ast at the rate of one yard in 
nearly e\ery twenty-two years. 1 doubt whether any 
rock, even as sotl'aa chalk, would yield at this rate 


eKipliiijf i»ii the m«)«t *>\(M>i4(>ii rnantu ; thi>ii;r)i im (louht 
tliH detfTadatioii ot h lofty rlirt would lie mor*- ia|.id 
from the hrt*ak;uf«» *>f th«» fallen fVajfineiitj*. < 'n the 
other hand, I do not h«'li»n«« that any line of coa-xt. ten 
or twenty miles in lontrth, ever sutferH detrradatioii .it 
tiie Haiiie time alone it^ whole itidetited lentrth ; and we 
muKt reinenUicr that almost all "itrata eonfiin harder 
laven* or noduh-*, whirh froni lonu' resi.stinj; attrition 
t'orm a hrtak water at the ha«e. We may at leawt 
foiilidently helieve that no roeky roast ."i^x* feet in 
heijfhl commonly yields at the rate of a fiK>t per 
ceiiturv ; f<»r ihit would l>e tlie »arM«' in am<»iint ax a 
rlitf one yard in height retreatiiiir tw»'lve yards in 
twenty-two yearn ; and no one, 1 think, who h.i>i care- 
fully oljser>ed the shape of old faih-n fraiimenfx at the 
liA>e of cliffs, will admit any n>Mr a|ipriia(h to such 
rapid wearing away. Hence, under ordinary circum- 
stances, I stiould infer tliat for a cliff ."»(«» feet in heitrht, 
a denudation of one inch |>«'r century for the whidc 
lenjfth would he a sufficient allowaiu'e. At this rate, 
Of! tlie ahnve data, the denudation of the \\'eald mu-t 
have re<jiiired .'><>•;, »»t)i',4<Hi y»'ars ; or sjiy thr«'e hundred 
million ye-irs. liut jierhafis it would !'»• >afer to allow 
two or three inches jwr <'entijry, and this wmild reduce 
the number «>f years to one hundred and fifty or one 
hundred million ve.irs. 

Ihe action of tresh water on the trently im line<l 
^^ ealden district, when upraised, could hardly have 
i'cen trreat. but it would somewhat ri^luce the alntve 
estimate. On the otlier hand, durinu oscillatiotis of 
level, which we know this area underjrone. the sur- 
face may have existed for millions of years as land, and 
thus have escaped the action of the st:i : w lien deeply 
siiltmer;j'e<i for perhap- ciiiially lonir perifxls, it would, 
likewise, have escaped the action of the <oast-waven. 
>o that it is not improliahle that a lMn:."'(«r period than 
•'i<x) million years has elapsed nince the latter part of 
the Secondary period. 

I have made these few remarks l»ecau«»© it is hiffhly 
miportaut for us to g^aiu Home notion, however ifn[>erfect. 




of the lapse of years. Duriii!,' each of tb^se years, over 
U<e whole world, the laud and the water has been 
peopled by hosts of living forniK. N\'hat an infinite 
number of jfeneralions, which the mind cannot gra-ep, 
must have succeeded each other in the lontr roll of 
years I Now turn to our richest treolo'.'-ical museums, 
and wliat a paltry «lisplay we behold I 

'in I fit' jinunieuM "f cur I'uUvdiitnliKjicid colif tioriM. — our |i.ilifontulot:ical collections are vory im- 
jxTfect, is admitted by every one. The remark of 
that admiralile pala'oiitoloirist, the late Kdw.inl Forbes, 
shoiibl n(»t he lortrotten, namtdy, that numberx of our 
f (ssil H|i«'i ics are known and named from sintrle and 
often broken spec'inens, or from a t'cw specimens 
collected on some one spot. ( )nly a Hmall portion of 
the surface of the e.irfh has been p'eolo^ically explored, 
and no part with sutHcient care, as the important di»- 
coxeries made every ye;ir in Europe prove. No 
ortranism wholly soft, can be preserved. Sliells and 
bones will decay and disappi-ar when left on the 
bottom of the sea, where sediment is not a«-cumiilat- 
inir. I believe we are continually taking a nio^it 
ernmeous view, when we tacitly admit to ourselves 
that sediment is bein« deposited over nea;ly the wlioie 
beil of the sea, at a rate sutticij-ntly ijiiick to embed 
and preserve fossil remains. TliroiiL'lio'it an enor- 
iimiiMy larf:e proportion of the ocwiii, the britrht blue 
tint of the water l>espeaks its purity. The many cas<»s 
on record of a formation conformably covered, after an 
enormous iiiler\al of time. l)y another and later forma- 
ti«)n, without the uuderlyiiiir bed tiaviny: sutl'ereci in 
tlie interval mv wear and, seem exjilicable only 
on the > lew oT the bottom of the >^ea not "irely lyinjf 
for aL'e> in an unaltered condition. Ttie reinaiiis 
which do liecome embedded, if in sand or gravel, will 
when the beds are uprais'.d generally l>e dis-sohed by 
the jieri olation o.' .-ain-water. i siispe<'t that tiut few 
of the verv many animals wlsicli live on the beach 
betwwn Li^rl' *'»! low watermark are pre.served. For 


in.uuue, the several Hi.e.Mes of the Tl.t ...aliim' (a 
-ub-far ilv of M.shilo cirrip.xles) coat the ro.-!. - all over 
the world in intinite uumlK^rs : they are all vtnctiy 
htt<.ral, with the exception of a Rinde MediUTraneai. 
-neiies, which inhahib* dee^. water and has been tound in Sicilv, whereas not one other specie, ha. 
hitherto heen 'found in any tertiary formal..,i. : yet it 
isiiowkiK.wM Ihattbe L'cmisC hthamaluseMsU'ud.irn.- 
the chalk i-criod. The incdlu.can Kt'MUS C hiton oHers 
a nartiallv anal<>i,M)U!» ca-c. 

With respect to the terrestrial oroducticn. which 
lived during the Secondary and i'alieozoic periods, it 
1. Kui.crduous to state that our evidence trom fosMl 
rcman.s is frajrmenUry in an extreme detrree. .-r 
in^tan. c not a land shell is known bcloiiKi'i^' to either 
of Mie^e %ast periods, with the exception ot ono sj^-cies 
discovered hv Sir ( •. l-vell and Dr. Dawson n. t.u- 
carlK)niferou8 strata of North America, of which slu-1 
heseral smM-iineii^ have now heen collected. In rotfanl 
to mamnuterous remains, a sinirle frhuu-ii at the 
In-t.-n. al taMe published in the Supplemei.t to l.vell s 
Manual, will brintr home the truth, how accidental and 
rare is their preservation, far better than piures ot 
detail N<>r is their raritv »urj.risintr, when we re- 
meml>er liow lar^^e a proportion of the hi.nes ot tertiary 
mammals have been discovered either in caves or m 
l.uiistrine dep.K.t- ; and that not a cave or true 
lacustrine bed is known »)elonKinjf to the atro ot our 
M-condarv or paheoioic formations. , • . 

But ti.'e imiMTfection in the ^eoh.^ record mainly 
re<ults iVnm another and more impurtant cause than 
anv (.f the mreiroimr : namelv, from the several torma- 
timis beint; separated from Ciich other by wide intervaU 
of time. \\ hen we s«>p the formations Uibulated m 
written works, or whei; ve follow them in nature, it i« 
dithcult to avoid liflievintf that they are closely con- 
liut we know, for instance, from >i. li 

>.t'i utive. 

rviurciiisuii s »i'«*ai w 
tiicre are in 
formations ; so i 


that rountrv between the superimposed 
i iH in North America, and in many 




I> ? 

< 1 

1 1 
l< ' 

otlinr parts of the world. 'Hip nio^t skilr'ul treolotfist, if 
his att»?titioii hail l»e«Mi extliisivcly cnnfiiioH to these 
lartre territories, would never have siisj>e(ted that 
•lunriir the periods whiih were hl.iiik and harreri in his 
own country, trra-it piles of sediment, charfred with 
new and peculiar fonns of life, had elspwlicre heen 
areutniilated. And if in e;teh separite territory, hardly 
any idea can l)e f<irrned of the lon^'tli ot time wliieh has 
el.i|ised between the coiiMMMitive tunuation-;. we may 
infer th.»t this could imwhere he a-certained. The 
fre(|uent and irreat chanji^es in the tniii(»ra!f>L'icai coni- 
|i i-ition of c»nisecuti\e tormations. (."-encralh' iinpl\'in$r 
^;reat chancres in tlie ireotrraphy of the surroundintr 
lands, whence the sediment has l»een derived, accnrd^ 
^v:th the l>e!i»>f of vast intervals of time lia\ iriif e!ap>»'d 
lietwiM'ii each formatinn. 

IJut we can, I think, see why the ireolojrical forma- 
tion* of each rcLriiui ;ire almost invariahly intermittent : 
tliat i-. have not ;i 'lowed fach other in close seijiieiK'e. 
Scarcely any fact struck me more when examining' 
main- hundred mile- of the South American coasts, 
Ah ("h liavf heeti upraised se\era! hundred feet within 
•he recent period, than the al»se!ice of any recent 
deposits sufficiently exten«-i\e to last for even a short 
^ period. Alon::- the v*}iole west coa-t, which 
is inhabited hy a peculiar marine fauna, tertiary beds 
are so poorly developed, that no record of se\cral suc- 
cessive and peculiar marine faunas will prohably \k> 
preser;ei! to a distant aire. .\ little re(iecti"M will ex- 
|dain why iluni: the ri-mu coa-t of the we>t"rn side of 
^•outh .America, no extensive formatituis witii recent or 
tertiary reniaiii- can a:i\\vhere lie found, thoni.'!! the 
-uoply of sediment must for .i;res liave been i:reat, 
from the enormous dcirradation of the coa-t-rocks and 
from muddy streams enterinj; the se.i. The explana- 
tion, ii(> douitt. is, that the littoral and sub-littonil 
deposits are continu.i!!v worn away, as sr^nri as they are 
brouclit up li\ the slow ami irradual risitiir of the laud 
"ithin the ^'rindinir action of the coast.-w;i\ es. 

^^'c may, I think, -afelv conclude that se<limci;i. 



must l>e accumulated in extremely thick, solid, or 
extensive ma>*es, in order to withstand the in.e>sant 
acliou of the waves, when first ui)rai>ed and during 
MiU^equent oscillatHins of level. Mich thick and ex- 
tensive accumulations of sediment may »'e forn.ed in 
t^^o wav>; either, in protound depths ot the <ea m 
wlu.h ciise, iudKHM- from the researches ot E. lor .e>. 
we mav conclude that the hott<.m will he mhihited hy 
i.xtr.-..iclv few riti;inal>, and the ma>s when upraised 
wiiltfivea most iinperlert recrd of (he lontis ot liN 
n-hii h then existeil ; or, sc.iiment may l-e a.curnulate.1 
to aiiv thickness and extent over a shallow Uittom, iJ 
it c.uitinue sh.wlv to suhside. in this latter ca-e. as 
loiiK as the rate «.V suhsiaenc- and sii].ply ot hedimeut 
n.Mrlv hahmceeach other, the M-a wul remain shallow 
aii.i favourable for life, and thus a fos^iliterous torma 
tioii thick enoujrh, when upraised, to rej<ist any amount 
of (letfradat.on, may he torined. 

1 am convinced that all our ancient tormatiomt 
which are ridi in fossiU have thus heen formed durtini 
sut.>i<len<e. >iuce puhlishiii»r my views on tliis suhject 
in ia4.'). I have wat.hed the pro^'ress of (ieoloffv, an-: 
ha\e t-een surj.rise.i to note how autlior after author, 
in trealinu^ of this or ureat formation, has come to 
tlie conclu>ioii that it wa- accumulat.-d dnrintr suhsid- 
eiice. I niav add, that tiio only ancient tertiary torma 
tion on i!ie we>t c oa-^t of South Ame-ica, wiiich has 
heen Imlkv enouuli t.- r.-ist such deirradation as it h.i.-, 
aa yet suffered, hut will hardly last to a disUnt 
tri.ol(.m<al ai'e, wa- certainly dejKiMted durin^; a down- 
w;,r.i o^ciilaUon of level, an. I t!iu« grained consulerahle 

All tr.'oloirical facts tell us plainly that each area 
has uncli-r-one numerous slow osriHatioiis of level, and 
apparently the>e oscillations have ath-. ted wide spate* 
t on>e'iueiulv formations ri<h in fo-siU and sutliciently 
thick and exlmsive to resist Puhse<juent desfradation. 




Ilia\ iiave tirt-n iOrmC-ti err v.;;!i- • ;;.;t r? tj-^j::::;; ]• 

of suh<i.ieiice, hut onlv where the ^ui.ply of se.limen'. t.) keep ''.e M-a ■.!:allow and to e-nled nv-. 



jiit'scrve tln>! roni.iiiis Kcforn tlicv liail tune to deca'-. 
< H\ the otlitT haiirl, as lomr as tlit» bed of the ^^ea re- 
mained stationary, tfiirk deposits could not have Ikmmi 
acciiirinlated in the sIimIIow j>art>, whii )i are the most 
!av<iiiraMe to life. Mill lf>s could this have haj)[>encd 
diirinjr the alternate iienoiis of elevation ; or, to speak 
more accurately, the Weils which were then accumulated 
will have heen <ie-.troyed l>y heintr upraised and hroujfht 
within tlie limits of the coast-action. 

I hu" the treoloirii-ai record will alniDst ncte^^ir !v Jie 
rendereil intermittent. I teel mucli coiitidence in the 
truth of these views, for tliey are in strict accord. u.ce 
with the tferieral principles inculcated hy Sir ( . Lvell ; 
•iiid K. Forbes sul»se<iuently hut indejicndently arrived 
it a similar conclusion. 

(•up remark is liere worth a passing"" notice. During 
perioils of elevation the area of tin- land and of the 
adiuiiiin^' shoal j»arts of the sea will be increased, and 
new -tations will otlen be formed ; — all circum^tani os 
most favourable, as previously e.xplained, for the forma- 
tion of new v.-irieties and species; but durin:,' such 
periods there will trenerally lie a blank in the >,'-eoloM;i(al 
record. On the other hand, duriny subsidence, tiie 
inhabited area and number of inhabitants will decrease 
(except in«- the productions on the shores of a I'ontinent 
when first broken up into an arcliipela^o), and conse- 
quently diirin^r subsidence, thoutrh there will l>e much 
extinction, fewer new varieties or species will be formed ; 
and it i.-t durini; tliese very periods of subsidence, that 
ourtrroat deposits rich in fossils have been ao umulated. 
Nature may almost be s.iid to have guarded a:r:iinst 
the Jre(|uent discovery of her tran-itional or linking 

I roin t)ie forejoin:,' consideration^ it cannot be 
doubted tiiat the ireolojfical record, viewed as a whole, 
is extieriudy imperfect ; but if we contine our attention 
to a!i\' one formation, it becnioes more diffiriilt to 
understand, why we do not therein find closely 
t^saduaie'l '.arieties between the allied species which 
' \ «d at its CMin:iieV''<'Mic!it and ;it its ci(»r%e. ^o^■;^) 

iMl'KRhE(Tl(»N OF (lEOUKlK AL RECOKD 2fi3 

ca..'< :vr»- on re.-or.i of the same ^p^-n.'. present 
d.-tiu.t varieties in the upper and lower parts otliie 
-ame tormatic.ii, but, as they are rare, they may be h.;re 
„asse.l over. Altiiouch earh formation has m- re.iuired a va-t numher of years tor it^ 
.iep<»Mti..n, I .an see se\eral reasons whv each shouhi 
„t include a graduated series of links between the 
.neries which tJ.eii lived ; but I can by no moans -tv 
•!.nd to a.s-i:rn due prop<.rtional wei-ht to the t..llo« mir 
considerations. , 

MllK.utrh earli formation may mark a very 1 uij; l.ip>e 
:,i vears, each perhaps is short compared v th ti.e period 
rc.i'uisite to chanire one snecie^* nito .ui..iher. i •'•ni 
*w!ire that two i>ala^untoloirists, whose opiniona are 
worthv of much deference, naniel, Bronn at d U ood- 
*ara have concluded that the aveni^re duration oi each 
form'itiou is twice or thrice as Ion- a^ the aveni^e 
duration of specific forms. But insuperal)U> dithculties, 
an it seems to me, prevent us cominjf to any just 
.onclusion on this hea.h When w. see a species hr^t 
aupeannjf in the middle of any formation, il wo<ild \>e in the eitreme to infer that it had not elsewhere 
previously existed. So a^rain when we find a xp.-.ies 
disappearing? before the uppermost layers have been 
deposited, it would l.e equally ra-h to suppose that it 
tiien }«H-ame wholly extinct. N\e fortret how small 
the area of Europe is compared with the rest of the 
^orld ; nor have the several stajres of the same f<ima- 
tion throughout Europe been correlated with pcriect 

With' marine animals of all kii.d-, we may safely 
inter a larpe amount of miu'-t^tion during chmatal 
xxid othrr cluujres ; and when we see a -pecie^ first 
;ipiK'a-iii- in any formation, the pn.bability is that it 
..nlv then first immi^rrated into tliat area. It is ^vel 
Known, for instance, that several species appcired 
m,mewiiat earlier in the jKiIwozoic beds of North America 
than III those of Europe , Lime ii-i^.r.t; 5j.}>.»rr::t:y ^n 
required for their miurntion from the American to the 
KuroiKjan se^w. In examining ttie latest deposita of 




viiridijs fjiiarters of the worlil, it has pvfirvwhere U^n 
iiotcri, that -nnie f'«'w still exivtin^r Hptv-iuN are rommnri 
in the <i»'[M)-it, but have l»«(<)me extinct in the immedi- 
ately -^urniuiwliiitr sea; or, roiivt'r-.'ly, that «ome are 
now al)umiaiit in the iiei^jhlKturiiiif -t':i, hut are ran- or 
ahseiit in this (leposit. It is an exrellent 
lesson to rt'tlfct <>:i the ascertained amount of niitrrati'if. 
«»t the inli.iliitant". ui' Kiiroj>e diiriiiir the (ilacial period, 
whicli tortus only a i»art of oin' w nole L'eolotrical period ; 
and likewise to r.tlcct «»n the (rreat changes of levnl, 
on the inordinately (rreat ctiantre of climate, on the 
prodi-ious lapse of time, all ini Itided within this same 
fflaci.ii perio.l. ^ et it may he douhted wlu'ther in any 
<]uarter of tlie world, sedinientary deposits, inrludtrin 
fotnil remahis, have pone on accumulatimr within the 
saoio areaduriiii: the whole of ttiif. |H!ri(»(i. It is not. tor 
inKtancp, proltabie that sediment was deposite«I durine^ 
the whole of the jrlacial period near the month of 
the MiRsissipjn, withni that limit of depth at whii h 
marine nnimals can flourish ; for we know what vast 
jreoeraphifril rhaneeso<curre(i in other parts of America 
during lliis space of time. \V hen such }<<><ls as were 
deposited in shallow water tuvir the mouth of the 
Mississippi during some part of the glacial |>eriod shall 
have hcen upraised, ortranic remains will [iro'twihly first 
appe.'ir and di8apj)ear at different levels, owinjf to the 
migration of species and to ireotfraphical chantres. .\tid 
in the distant future, a ireol<»L'-ist examining these l)eds, 
mieht 1)6 tempted to conclude tliat the avcraire duration 
of life of theemlH»dded fossils had U^en less than that 
of tlie fflacial period, ins-tead of haviriir hcen rr ally far 
irrcator. that is extendiuir from before the f^lacial epoch 
to the present day. 

In order to i^ct a perfect trradation betwcri- t.vo forms 
in the upper ami lower jKirtsof the same formation, the 
de|>osit must have g'one on accumulatinjj for a very lonif 
period, in order to have jriven suthcii-nt time for the 
slow process of variation ; lience the deposit will jretier- 
ally have to be a very thick one ; ami the spociix* 
undcrffoirijT modifi<-at:on will have h.i.i to l.^e on the 




^»me ar*"* throughout this whole time. liut we have 
M-i'U tliat a thick fo^^Mlitrrous formation can onl\ l« 
a.-.Mimwlatril diiriiifr a p'TJod of suhsi.h'iice ; and to ket-p 
the ai.proximat.-iv the Hanie. whi.h is nf'«-.«ss;iry 
i,. nrrU'r to ♦■nal-le tlie same Hi>e<-ies to hve on tio- -ame 
,t,;..-.. the ^ of s.dimeiit must n.-arly have cnunter- 
■sii.ui'.e.i the Mmount of siil.Maence. But thi-. same 
niovment ..f -Ml.M(leu.e «ill often tend to sink the 

ir.M w},.-n.e tl dimei.t is drrivi-.i, and thus dimansi. 

•1„. Mi|.|.lv whilst the downward movement eoiitinues. 
In fa.t. tiiis n.arlv exact halan-in- l.etv»een the suj.|. y 
d ..Miiment and the amount of sul.Mdence is i>rolai)ly 
irir.Tuntinu'emv ; f..r it h;i> he.-n oh-erved hy more 
than on.. i.aheont..lntr;st. that very thick deiKi-its are 
o^iiallv kirren of orirani. remains, exc.-pt near 
lij.per <ir lower limit-. 

it would M-em that .-ach M'parate formation, like tlie 
A hole pile of format :nns in any ...untry, fa- ueneralh 
.*en intermitteni in its aetniP-.ulation. \V hen ^•; -«e, 
a.^ 1- ^o often th.- cJi-^e, a f..rmalion .-omp—ed ot UmIs 
of miii.rr.lotfical ,om|..»sit:nT,. we may reason- 
« ilv -uM.ect that the of depu-ition lia.s hven 
mil', li -nterrupt.-.i. as a .liani.'.- in the currents of the 
-.M and a supply of -..dimenl of a diiT.Tent natur.' will 
zeneraliv have' been <lue t<» fr,.,.trraphi.vil changes 
re.jnirinir much time. N..r will the .lo-.-^t inspection of 
a formation give anv idea of the time which its deposi- 
tion has .-on-umed. Manv instances could he ^nven of 
lH>dsonlv a few Let in thickne>s, rcpre.-.entii:>r forma- 
tions, el'sewli.Te thousands of feet in thickness, and 
which must liave reijuir.'.! an enormous period for their 
;ucumulation; yet no on.- i;fnorunt of tins fact would 
have su>p.M ted the hip-e of time represented hy 
ti.e thinner formation. .Man) cases <ould l»e jfiven of 
tlie lower heds of a formation liavinij heen uprai<e«i, 
d.'nialcd.sut.ine.-^-ed,and then r«^covered hvthe tip|„r 
Ks'ds of the vame formation, fari.-, >.ho»inu what w;d.-. 

accunuiiation. lu other ca>es we have the plainest 
evidence in irreat fo-ilised tre*'s, stHl standiiiT uprmhl 



a- tlicy ^'rf\r. f.f many loiiu'- intervals of time and ch.injfes 
of h'vrl .liiriiiir tlip process of deposition, whirh would 
n<ver t'vi-n hav« l,.M-n sii<i.»'(t«-d, had not tlie tr.-es 
rliancj'd to hav«' I..'.ti t.r.-scrvcd : tlin> Messrs. Lyt'Il 
an"i I),iw<on toiiiid tarlionifcroiis beds M(m» feet thick 
m Nova Scotia, with ancient root-F)earin;r strata, one 
al>o\(« the other, at no less than M,ty-«i^ht different 
levels. Hence, when the same species (M-riir at the 
l>ottoin, middle, and topo'a formation, the prohahility 
IK that they have not lived on the >ame s[)ot during the 
whole period or drjM.sition, hut have disappeared and 
reapi-cared. perhaps many times, duruiir the -ame jfefH 
loiTical periu.i. So that if such sj.cfies were to under-ro 
i coiisideralue amount of modification durintr any one 
u^'olo^firal period, a section would not prohahly in'clii<le 
all the tine intermediato (gradations which must on my 
theory have existed het«een th.-n,. hut ahruj.t, thoui^h 
perhaj)s very sli^rJit, ch.infres of form. 

It ii all-iiiiport/iiit to rememher that naturalists have 
no iiolden rule hy which to distinguish species and 
varieties ; they {rrant Home little variahilitv to each 
species, hut when they meet with a somewhat jrreater 
amount of difference hetween any two forms, they rank 
hoth as species, unless they are enabled to connect them 
U)}rether hy close intt'rmediate pradalioiis. And this 
from the reasons just assiCTied we can seldom hope to 
effect in any one jreolojncal section. Supposing; H and 
(" to Ihj two sj.ecies, and a third, A, to he found in an 
underlyinff hed ; even if A were stri( tly intermediate 
'.etwoen H and ( , it would simply he ranked as a third 
and distin<-t species, unless at the'same time it could be 
iiio-t closely connected with either one or both forms bv 
iiii.rmediate varieties. Nor should it be for^rotten, as 
I'cfore explained, that A miirht be the actual progenitor 
• r M and ( , and yet mit:!it not at all necess.irily be 
strictly intermediate hetween them in all pc.ints of 
structure. So that we mijrht obUiin the parent-sT>ecips 
anii it.s several modified descendants from'the lower and 
iipl)er beds of a formatioji, and unless we obtained 
riu.'Mer.. 's ttansition.J ^:,.f aUw^, we should not irco^f- 



.. ,.. thoir n'Ution-hip, .'"..1 should con.o.juently l-e 
; .,:n,M.ll...l to rank th.-rn all as distm.-t '"r;T^.^ 

It'is notorious on v.hat excessively sl.uht d.fferen.-.- 
„,;.„'ontolosri^t- have founded tlieir spenes ; and 
,h..v'd.. this tl... mnn. readily if the specimen- 
.ru,n .li.rer....t sub-Ma.M-s of the same formatu.n. Some 
..M.eiien.-ed .on. hnin-ists are now sinking inan> ot the 
V vie spe.-it.s of in )rhi.^ny and oth-rs mto the rank 
ot7ar:eli.-. ; and on this view we do hud the k.nd ..: 
,.,„,,„,. „t rhan.^e ^vhi.h on my theory wo outfht o 
^nd M<,re..v.r, ir-N^elook to rather w,der intervaU, 
„.,nelv. to distinct hut couHe<-utiv^ Htnire. of the san-o 
M-eat t..r,n.ti..n. ^e fuu\ that the emhe.l.ied toss U 
th..u,h almost ,.n.ver<ally ranked as .peclically dJ- 
fercnt vot are far more ch.sely alued to each o'hrr 
than are the species foun<l in widely se,«rated 
forn>ations ; hut to this ...hject I shall have to return 
in the tollowiiii; chapter. • i • i 

( ,„.. other ronsiderav.on is worth notice : with animals 
ind i.lants that can propii^ate rapidly and are not 
hi-hlv locomotive, there is rea.son to sus{«M-t, a> we 
ha*"ve iorn.erlvseen, that cheir varieties are ironerally a 
iTst local ; and that su.h varieties do not spread 
widelv an<l supplant tlieir parent-forms until they Have 
h,.,M, n.u.lifie,! and perfected in some considerable 
.•,.^r..e Accordinu' to this view, the chance of dtscover- 
inR in a for.natmu in anv one country all the early stages 
,.f transition between anv two forms, is small, tor the 
su.-.essivpchanires are suppose<l to have been local or 
,-, nned to some one spot. Most marine animals have 
•i vide nm^e : and we have seen that with planta it is 
thwe which have the widest ranjre, that present 
, .rieties • «o that with snells and other marine animal-, 
I is probably tViose which have had the widest rniiire, 
• ;r'exc.T,i III,' the limit> of the known ffeolosical }..rm:i- 
tiuns of Knrope, which have oftenest jriveu rise, hr>t 
to local varieties and ultimatelv tone^- specie ; and 
thi-i a^ain would jrreativ iesseii liie chrti.. o or i>:;r ;:riiiu 
ii)lo to trace the stages of transition in ciiy one 
'eo'o: i-;t! forinat'ofi 




It Hlioiild not he forgotten, that at the prenent dav 
with i..Tf.vt spenmoiiH for exaniiiiati..ii, two t(,rm« carl 
«eJ.Jom be .omioctr.l l.v interm.'diate varieties and thti« 
prov.Mj t.. l>e the sam« ^porie-s, until manv snerimen- 
bave U.,.n rollerted from manv p!a. v.s ; and in the 
<a«e of fossil Hpeoies this could ran-lv he effected bv 
pai;v„ntol(,i:i,t.. We shall, perhap>. Ik^I perceive the 
iriiprohahility of our i.einjr enahh-d to connect npe.iet. 
by iMimeroiis, tine, intermediate, fossil ]i„ks, bv asking 
ourselves wln-iher, for uist.ince. ceoloyi.f.s at some 
future jM'riod will l>e able to prove, tliat our different 
bre.-d. ot cattle, sheep, horses, and d..-s have descende.l 
from a si rifle Kto«-k or from several ahoricm.-ii stocks- 
or. airam, uliether certain sea-hhells iniial.itin^r the 
shores of North America, which are ranked l.v some 
concholoiTi^ts as distinct spe. ies from their Kur..i,ean 
repreMM.tatives, and by other con.-holo^nsts a.s onlv 
var..-ties are really varieties (.r are, as it is called' 
Kptcirically distinct. 1 his .-ould he effected onlv hv 

tie future ^reMlot:istdiscoverin»r in a fossil st;itenumJrous 
;nterme<liate >:radati.»n.s; and such huccckh seems to me 
imfiruhahle in the hitrhest detfree. 

iM-olotfical research, thou-h it has added numerous 
species to existirij,' and extinct genera, and has made 
the intervals between some few g^roups less wide than 
thev otherwise w(.uhl have heen, vet has done scarcelv^f m hre;ikin:,' down the distinction iKJtweeh 
-^I'c.ies, by connectinff them together l.v numerous 
tin.-, intermediate varieties; and this not 'havin^r heen' 
erfected, is prohahly the >rrave>t and most oI.mous of 
all the many objections which may he ur^red aijainst 
'ny Mews. Hence it will ho worth while to sum up 
the t<.re:r(.intr remarks, under an imadnarv illustration 
Jhe .Malay .Vrchipela-(. is of about the size of Kurope 
from the N..rth ( ape to the Mediterranean, and frot. 
Hritain to Russia; and therefore equals all the ^eo 
I'.trical formriti«.ns which have l.een examined with 
a:, y accuracy, excej.tin^' those ot the I nited Mates of 
America. I fully a?rea with .Mr. (iodwin • Au>ten, 
that the j.resent condition of the Malav ArchijK'laiTo' 


v^ilh its 1 .n:P islandn separated by wide and 
-J.allow 8«is reprrMM.ts tho tormer statn of, whilst m..>t of our formations Hor« ac.umu- 
ati.ii Tho Malav An-lupchMfo i.s one of the richest 
r,..ri,„;s of the whofe >*orhi in orjfauic; hew.jfs; yet it al 
■C .mM-if. were to b«, onUe.-ted v,hi.-h hase ever Ined imperfectly would they represent the n.itural 

• ii^torv of the world ' , . .1 . 

Mat' wo haveeverv rea.s<.n to V»elieve that the terren- 
tna! nrod.H-tioiis of the arrhipela-o would In- pr.-.erved 
it, an ex. .-HMvelv imperfect manner m tho formations 
svhM-l. v^e suppu.'e to U there acrumulatun:. su^pe^t 
that not manv ..f the stri.tly littoral animals, or o 
,l,n.e whi.h lived on naked Mihmanne nu-ks, nuul.t 
t,.. ; and those einhedded in t-ravel or sjuid, 
would n..t endure to a .listant ep<Hh. U herever sedi- 
ment did not a.Tumtilate on the l.ed of tho sea. or where ,t 
.li.l ,i.,t accumulate at asutRcient rate to protect orir:i,nc 
K„.li,.^ from de.av, iw remains could he pre-erved. 

I hel'.-ve that t".'.ssilifen.u> formations could he t..rm.vj 
HI the arrl.ipei:iir<.. «t' thickness sufficient to hist to an 
■ i^ di-tant in futurity as the second;-ry tormatioiir 
lie in the past, onlv duriujf p-riods ol suh-idence 
•I-h,..e t.eri.Hls of suhsidence wc.uld ho separated from 
.-uh other l.v enormous intervals, durin- which the 
area would he either st:iti(mary or risinir ; «h Ut risins:, 
each fo->iliforou-. formation would he destroyed, almoNt 
ts soon as accumulated, hv the incess;int co;uit-action. 
.IS we now see on the shores of South America. I>unnt.' 
the peri'xis of suhsidence there would prohahlv be 
much extinction of life; durinjr the periods (d eleva- 
tion, there would he mu.h variation, but the treoloirical 
record would then he lea-t perfect. 

It miy he douhted vvhether the duration of any one 
Teat period of sulKid.'iice over the whole or part of 
the archipelairo, to-ether wih a contemporaneous accu- 
^,,. !.<;..!! of w.flim.'i.t. would ejrret-ii the avenure dura- 
lion of the siime >pec tic forms; and these contintrencie.s 
are indispensahle for the preservation of all the transj- 
tional uTadaiions between any two or more species If 


AN'^i .ind ISO TEST CHART No 2 




1^ 2.8 


u. m 2.2 

!: m 

t a- 








•er. Ne« "o'k 1*6 
*82 - 0300 - Phone 
^'88 - 5989 - Fa. 



hiirh trradatioiis were not fully prestTved, tr.nisitional 
varieties would merely apiM-ar as so many distinot 
Kpccies. It irt, al^o, prohalde that each threat period 
of Kuhsiiloiice would lie interrupted by oM-illations of 
level, and that sli>rht cliiiiatal chan;;e> would intervene 
durin;; such lengthy periods ; and in thcM? cases tlie 
inliahitants o.*" the arrhi|>el;uro would have to niiirrale, 
and no closely consecutive record of their modiricatioiw 
could he preserved in any one fornmtion. 

\ery many of the marine inhaliitants ol the archi- 
|»elaj;o now rariire thouKiimls -f miles beyond iU con- 
tines; and anal(.f,n- leails me t(» believe that it would be 
diiefly theM> far-raniriii;r >po.i,.s which would oflenest 
produce new varieties ; and the varieties would at tirst 
L'tMierally be local or confined to one place, but if 
posse^ised of any decided advant;ure, or when further 
niodihed and improved, they would slowly spread and 
supplant their jKirent- forms. When such varieties 
returned to their ancient homes, as they would dirter 
from their former state, in a nearly uniform, though 
perha])s extremely sliirht dejfree, they would, accord- 
intr to tJie principlt^is ffdlowed by many pala-ontolo^ists, 
be ranked as new and distinct species] 

If then, there be some dcirree of truth in these 
remarks, we have no rijrht to expect to find in our 
j^eological formations, an infinite numWer of those fine 
transitional forms, which on my tlieory assuredly have 
connected all the past and present species of the same 
jfroup into one lonj; and branchintr chain of life. We 
outrht only to look for a few links, some more closely, 
some more distantly relatt'd to each other ; and the.^e 
links, let tliem be ever so close, if found in different 
st;i^'-es of the same formation, would, by most palieonto- 
loa-ists, l>e ranked as distinct species.' Hut 1 do not 
pretend that I should ever have suspected how po-.r 
a record of the mutations of life, the best preser\e(i 
teoloLMcal section prasenttxL bail not the 'litlicultv of nur 
not discovering innumerable transitional links between 
the spei'ie*. which apinvired at the commencement and of ivicli forniation. prcjvsed so hardly on my theory. 



(m the Hidden af>}>^iir'ince uf whole ijronpi of Allied 
Sperien — Tlip ahrupt maimer in wlii.-h whole ffroups of 
S.ecie« suddenlv Hi.i..-.-ir \n certain furmations, has het'u 
urce«l by s.-veml paliPontolo^isL-^ - for iiistatire, by 
Xtrassiz/l'ictet. and hv none more forcibly than bv 
I'rofessor Sedtrwick-as a fatal objcrtioti lo the h.-li-t 
in the transmuUtion of sptMies. If numerous spe.ies, 
l)eloiurinir lo thi- same K«nera or tamilies, have really 
started into life all at ouce, the fact -ould be tatal to 
the theory of descent with slow nio<iifHation throujrh 
natural seWtion. For ti-.- development of a trroup o! 
forms, all of which have des.ende.l Irom some one 
j.rosfenitor, must have been an extremely slow process; 
'md the protfeuitors mw>l hav,- live-l ionK ••«!:•'> "*'^'""e 
their mo.litied descendanti?. Hut we continually <)ver- 
rate the i>erfection of the treolojjical record, antl falsM'ly 
infer, because certain ireiiera or families have iiot 
been found beneath a certain -t.ure, that they did 
not exist l.ef(.re that sta*re. U e continually tortrel 
how lartre the world is, comjKired with the area over 
which our ^eolotrical formations have been caretuUy 
examined ; we for^^et that irroups of si)ecie.- may else- 
where have Ion? existed and have slowly multiplied 
l)efore they invaded the ancient archipeluAroes of 
Kuro|>e an.'i ot the I'nitwl States. W'e do not make 
due allowanco for the enormous intervals of time, 
which have prol>ably elapsed l»ctwe'>n our consecutive 
formations, -lonirer i)eriiaps in most cases than the 
time required for the accumulation of each formation. 
ITiese intervals will have jriven time for the multipli- 
.ation of s|)eoies from some one or some few jKirent- 
forms ; and in the succeedinif formation such sjK'cies 
will apjHVir as if suddenly create«i. 

1 may here recall a remark formerly made, namely 
that it iuiKl't require a Ion? succession of a;res to adap- 
an organism to some new and jH'culiar line of life, ti»r 
inKl-anee to »lv thniiiirh the air; but that wiien this ha<l 
\ieen effected, and a few species had Ihu-. acquire<l a 
uTeat advaiit-;ure over other ortrani^m-, a comparatively 
short time would be necessary U» province nianydivrrireu* 









form8, which wouhl l»eahie to spread rapidly and widely 
throutrhout the world. 

I will ijow ^ive a few exanipjes to illuntrrite these 
remarks, and to sliow iiow li.ible we are to error in 
siipposiiiiT whole trnMjps or sjK'i-ips |i:t\e suddeiilv 
been pro.luoed. 1 may recall the well-ku(»wii tart that 
in {feol();riral treatises. puMislied not many vears at,^o, 
the trr<>;it class of mariiin.-i!s wa.s ahvays hpoken of a^ 
ha\ int' abruptly come in at the commencement of the 
tertiary series. And now one of the richest kn«)wu 
accumulations of fossil mammals, for its thickncns, 
l»elon!.'s to the middle of tlie secondary sei .'s ; and 
one true mammal him been discovered in the new re«l 
handstone at nearly the commencement of this throat 
series. Cuvier used to urye tliat no monkey occurred 
in any tertiary Htrattim ; but now extinct siHjcieM have 
been discovered in India, South America, and in 
Kurojie even as far l»ack a.s 'tie eocene stitre. Had 
it not been for the rare accident of the preservation 
of footsteps in the new red sandstone of the I'nited 
States, wlio would have ventured to suppose that, 
besides reptiles, n,, less than at least thirty kinds of 
birds, some of tfiarantic size, existed durinj,' that period . - 
Not a frag-ment of bone has been discu\ered iu tliese 
ImmIs. Notwithstandiiiir tliat the number of joints 
siiown in the fossil impressions c«)rrespond with he 
nuniU'r in the several toes of living birds' feet, some 
authors doubt wliether the animals which left the 
impre-sions were really birds. I ntil .juite recently 
these authors mit^lit have maintained, and some have 
maintr-iined, that the whole class of birds came sud- 
denly into existence diiritiir an early tertiary period ; 
but now we know, on the authority of "rofessor Owen 
(as may !«• seen in Lyell's Mnuwil), that a bird 
certainly lived during the deposition of the upper 

I ni:iv trive aiiotiisr In-^.tHnfe ifb!:'}-. 



passed under my own eyes has mudi struck me. In 
a rtiemoir on Fo>sil .Vssile ( irrif)edes, I have stated 
tliat, iroin the numl)er of esiHtinif and extinct ti>rtiary 

IMl'ERKECnuN OK iiE*)U)GlC:AL KE( OKI) 273 

frtim tli»> I'xtraortlinary rit»undatu-e of thp mdi 

»p<'».ie« ; 




worltl, trom 
Arctic regions to the e<iuaU)r, inhabitinjr various z«men 
i.r depths from the upjxT tidal limit-* to .'>»< tathoniH ; 
torn the perfect manner iii which xj^M-imen-* are pr»*- 
-iTved in the oldewl tertiary heda ; from the ea>e with 
which even a fragment of a v:ilve can l>e re. ..irnis<'<l ; 
from all these circum«t.iiu-es, 1 interred that had sesnile 
oirripedoH existed (luriii>f the >econdary i)erio<lH, they 
vrotil'l certainly have been prefer ve«l and diwovere*! ; 
and a:* not one species had then been discovered m 
l.edB cf this a^e, 1 concluded that this j^reat jfnmp liad 
tK?en suddenly developed at the commencement of the 
tertiary serie**. 'nii-* «»-•* a ^ore troulde to me. addiiii.' 
as I thought one more instance of the al.rupt ;inpear- 
ance of a srre^t trroup of siiecios. But my wnrk had 
L.vrdly »>een puhli-lied, when a skilful paUontnloifist, 
M. Hosquet, sent me a dniwiii^' of a perie.-t sp*M-imen 
of an unmistakable sessile cirripede. which he had 
himself extracted from the chalk of llelpum. And, h^ 
if to make the case aa strikinjc as possible, this ses..ile 
cirriiK'de was a ( hthainalus, a very common, iarjfe, 
and uhniuitous ifenus, of which nut one specimen has 
;i.s yet been found even in any tertiary stratum. Hence 
we n(»w jKjsitivel know that sessile cirnpedcs existed 
during the secondary period ; and the-e cirrijHnles 
might have been the'progenitors of our many tertiary 
,ind existing species. 

The cjise most frequently insisted on by j>alieont<il(>- 
iiists of the apparently sudden appearance oi a wh(de 
hrroup of species, is that of the teleostean fishes, low 
.iown in the ( halk period. 'Hiis group includes the 
l.irge majority of existing species. Lately, I'roh'SM.r 
I'urtct h:is carrieii their existence one Hub-^*a^P further 
back ; Htid some paheontologist- believe that certain 
much ul.i.r h^he.^, of which the affinities are as yet 
imperfiHtlv known, are rt^illv t«leostean. Assuming, 
however, that the whole of them did apin-ar, as Agassiz 
l»elieves, at the commencement of the ch*lk formation, 
the fact would certainly be highly rem-*rkable : but 








I cannot nee that it would be an insuf>eral)l<' difficulty 
on my theory, uiile.-is it could likewise l»e nhown that 
the H{>eciet( of this ^roup a(i{KMn>d suddenly and Himul- 
taueously throu^hcuit tne world at this (tame period. 
It in almoiKt superHuouH to remark that hardly any 
fossil-fish are known from south of the e<|uator; and 
l)y runninjj throu^rh IMctet's I'alif ontology it will be 
Keen that very few H|)ecieH are known from several 
formati(»ns in Kurope. Some few families of fish now 
have a confined rani^e ; the teleostean fish mijrht for- 
merly have had a similarly confined ranpe. and after 
bavins' been largely developed in some one sea, might 
have sjtroad widt-ly. Nor have we any ri};ht to suppose 
that the seas of the world have always l»een so freely 
ojHJU from Koutli to north as they are at present. Even 
at this day, if the .Malay Archipelago were converted 
into land, the tropical [>arts of the Indian ()c«au would 
form a large and perfectly enclosed l>asin, in which 
any great group of marine animals might be multi- 
plied ; and here they would remain confined, until 
some of the species became adapted to a cooler climate, 
and were enabled to double the southern capes ot 
Africa or Australia, and thus reach other and distant 

From and similar considerations, but chiefiy 
from our ignorance of the geology of other countries 
beyoiid the confines of Euroj>e and the J'nited States : 
and from the revolution in our palieontoloyical idea- 
on many points, which the discoveries of even the last 
dozen years have effected, it seems to me to be al>out 
as rash in us to dogmatise on the succession of ort^ini'- 
l>eiiiirs throu:rhout the world, as it would be for a 
naturalist to land for five minutes on some one liarren 
point in Australia, and then to discuss the uumiier and 
range of its productions. 



On tkf stuldm (ip^^-UTdfy^ of "tow^ of ALlif'.l Sticcii'.s 
in thf toirejit known fossiliferou* strata. — lliere is another 
and allied difficulty, which is much graver. I allude 
to the manner in which auml>ers of species of the same 





^roup, Hud(]pulv Ri-fPAr in the lowest known fossili- 
♦.roiii* ro<:ks. Most of the arjrumenti^ which have coii- 
finced me that all the existinp Hperies of the wniP 
■rroun have desrended from one proirenitor, apply with 
nearly e<jual force to Uie rarlie^t known spc<ie«. For 
instanre. I cannot doubt that all the Silurian triiohite- 
have dp^i ended from §ome one irusUcean, which mur-t 
have lived htn|r before the Sihirian aire, and which prob- 
ably differed greatly from any known animal. Nime 
of the most ancient Silurian animali, ah the Nautilus,, etc., do not differ much from living •qpecies ; 
and it cannot on my theory J»e Hupnosed, that these old 
species were the prosreniU)rs of all the species of tlie 
orders to which they l^lonjj, for tliey do not preaent 
characters in any de'tfree intermediate l>etween them. 
If, moreover, thev had l)een the progenitors of tbe>e 
orders, thev would almost certainly have been lou^r a*ro 
supplanted' and exterminated by their numerous and 
imp'"i>ve«l descendant-^. 

Consequently, if my theory be true, it ia indisputable 
that before the lowest Silurian irtratum wa*) deposited, 
lonjf periods elap-^ed, as* lon<? as, or prolably far lonirer 
than, the whole intenal from the Silurian a^re to the 
present day ; and that durititr these va«t, yet quite un- 
known, periods of time, the world swannod with liviiiir 

) the question why we do not find records of these 
va.-^t primordial f)eriods, I can (rive no satisfactorv 
answer. Several of the most eminent geolotri^ts, with 
Sir R. Murchison at their head, are convinced tha» 
we Bee in the or^ranic remains of the lowest Silurian 
stratum the dawn of life on thi.s planet. Other highly 
competent judges, as Lyell and the late E. ForlKW, 
dispute this conclusion. ^Ve should not forget that 
only a small portion of the «.»r]d is known with 
acciiracv. M. Barrande has lat^-ly added another and 
lower slaire to the Silurian system, al>ouniline with 
new and j>eculiar species. Traces of life have l)een 
dete'te«l in the liongmyud beds, Wneath Harrande s 
BO-called prim«.rdial zone. ITie presence of phosphatic 


ON I UK OKKilN OK S1*K( 1F> 

no'liilps and liitiimino'is in.ittor in nome of the lowest 

■i/oif rock-i, prnli.ilily iiuliiatfs the former existeiicp of 

life at these periodH. lint the (lirti<'iilty «»f uiulerstaiul- 

nn tlio nhseiire of v.i-t pilen of fo-.-'iliferoiiH strata, 

vliich on my theory no ilouht were somewhere rirTumii- 

Tte<l JK'fore the SilurKiii e{>oc}r, i^ very t.'r»',it. If 

;}i('-<- i!ii»-t ancient IhmIs liad hrcn v\ holly worn away 

liv dciiiKlation, or ohliterated hv m<'Tainorj»hic art ion, 

»«! oiiu'tit to tind only small remnants n{ the forma- 

Lions ne\;t siKveedintf tlnrii in aire, aj.d the>.e oiiirht to 

Ite very irenerally in a metam<>rj)hf)>ed condition. Htit 

•ju- df-criptions which wo now possess of the Silurian 

ie|>.i-~:t- o\«!r immf!i'~e territories in Russia and in 

Norlli America, do not support the view, that the 

dder a formation is, tlie more it has r.lways surieren 

he extri'mity of deniniation and nHtjim(»rpliism. 

I ho c^i>o at present must remain inexplicahlf : aii<l 
nay l>e truly iirtred as a valid aririifnent a^f-ainst the 
viow>i here ent»'r!ai!ied. Co -how that it may hereafter 
receive some exjilanation, i «ill L'ive the followinif 
hypothesis. I'rom tlie nature of the ortranic remains 
which do not aj)pear to have inhaliited profound depths, 
ni the several formations of Kiirope and of tiie I'nited 
>Uites ; and from the amount of sediment, miles iu 
thickness, of wliich the formations are composed, we 
iMiv infer t}i;it fmni tirst to last lart^e i<lanil- or tracts 
ot iand. whence the sediment wa- deriNcd, occurrwl iti 
the neirhl>oiirhood of the existirur continent- of Kuro|M> 
and North America. Hut we do m)t know what wa.s 
the state of thin^rs in the inter\als hetween the isiio- 
cessive formations; whether Kiirone and tiie I iiifed 
."^tates duriiijf these intervals existed as dry land, or a.s 
a suomarine surface near land, on « liich stMJiment was 
not dcjio-ited, oi- ii-s ti.e hed of an open .ind unlathom- 
atd" -ca 

Lookinir to tlie exi.-tin;.'' cneans. which are thrice -'i-s 
-'vlensive as the laud, we see them stuudc<l with many 
islands ; hut not one oceanic island is a.s yet known to 
aiford even a remnant of any pala»o/oic or secondary 
foruiatiou. Hence w .• foav perhaps infer, that durituf 


IMI»KKlhCTR)N OF (;K(>Uh;ICAL UK((>IU) 277 


the paltfo/oio and sr. ond.iry j.«T;o«ix. neither roiitiiu'iit- 
tu.r cnutiiiental i«l:ia(l- exUu-a when- our (x-eauti n.»» 
pxteiid ; for had they existed there, palipozoir and 
H.'eoniUrv forTiuitii.iis' uould in all |.ruiMih;lity havf 
l-een aeruruulati-.! fmni -e<l'Mieiit deriv.'d fr..-,' ■\\eiT 
wear and tear ; and ^oiiM have l»een at least part ailv 
.;].lMMve(i l.y tiie om inatioii> of level, whi.h we may 
tairU funcl'ii'ie rnii>t have )iitiT\«'neii duriinr these 
enormoiislv Invj; periods. It I'tu-n we may infer any- 
th'TiiT froiii th.-sti lattv, we nia\ infer that wh.-re our 
ocean-, now extend, iuve extended tn.m the 
remotest period of whi( h we liav.- imy re.ord : ami or. 
the other hand, that where .oatinent^ now e\i-t. lar-e 
tract.- oflai-.d lii-.e evi^t^-d, ^iihjerted m>> dn'iht to irreat 

o^tilialions ot level, since the silunan \ -od. 

Hi.' coloured map appended to my volume on ( or li 
llees, l"<i nie to e.iiiclude that tlie oceans are 
rttill mainlv areas o' suh^ideiice, the t:reat archtpela-oe- 
Ktill areas o I oscillations ot level, unil the continent- 
areiu. of elevation. IWit have we any ri:;lit to aK.sumt 
that thing's have thus remained from the l^'ifiniunc 
of this world.' Our coniinents '•eein to have l.een 
formed i>y a prepond«Tan.e, durintf many o«^cillations 
of level, of the tone of elevation: hut may not the 
areas of preponderant movt-ment have ciiaiiL'ed in ti..- 
lap-e oi^ au'e;*.' At a period immeiisurahly antecedent 
U> tiie Silurian epoch, continetits may have e.xi;sted 
where oceans are now spre^id out : a-id dear and open 
oceans may have existed where our continentn now 
HtATui. Nor shoultl we he justified in a-ssumin^ that if, 
for inst^mce, the hed of the I'aiilic Ocean were now 
converted into a continent, we should there tind forma- 
tions older than the silurian slrala.; nuch to 
have l>.'en formerly deposited ; for it iin;:ht well liappei, 
that istrata which" had huhsided some mjle.s nearer tr 
the tentro of the earth, and which had heen pressed 
(»n hv an euormouH we!;:hi of feupenncumhent water, 
rniirht have undert'one far more metamorphic action 
than straf.i which have always remained nearer to 'he 
rturlace. I'he immense area- in .^ome jwirt.s of ^he 

27 H 


wnrlil, for iiiMtariiu in >oiith Arnerira, of liare metA- 
morpliic rcK;kn, '*hich must have \)emu h«»ate<l under 
threat preM<4ure, have always* Hoemwd in mo to re<{uire 
Honw spetnal ex[ilaiiation ; ami vve may |>er}iaps believe 
that we see in the>e lari;e art-A"*, the many lurmatioiiM 
lonjf anterior to the wilurian eporh in a completely 
mpfamorphosed condition. 

'ITie several difliculties here di««<Misspd, namely our 
ii«»t findiiijf in the Hucresjiive formations infinite! v 
numerous transitional links between the many specie^ 
which now exist or havo existed ; the sudden manner 
in which whole j^roups of spcc.ies appear in our Kuro{>ean 
formations ; the almost entire absence, as at present 
kncmn, of fos>ilifer«uH formations beneath the Silurian 
'•trata, are all nndoubtedly of the ^Tavest nature. We 
see this in llie plainest manner by the fact that all the 
mo.«t eminent palaHuilolo^isLs, namely Cuvier, .\;:asgiz, 
Itarrande, Falconer, K. Forbes, etc., and all our trre.itetit 
<e<tloifist.s, as Lyell, Murchi.son, Sedjrwick, etc., have 
unanimously, often vehemently, maintained the im- 
mutability of 8{)ecies. Hut 1 have rea.Hou to believe 
that one trreat authority. Sir Charles Lyell, from further 
reflection entertains irrave doubts on this subject. I 
feel how rasti it is to ditfer from these authorities, tu 
whom, with others, we owe all our knowledge. Thosjs 
who think the natural treolojrical record in any decree 
pprti'c',, and wlio do not attach much weight to the 
facts and artruments of other kinds jfiven in this 
volume, will undoubtedly at once reject my theory, 
i'or my part, following out Lyeii's metaphor, 1 look at 
the natural treoloarical record, as a history of the world 
imperfectly kept, and written in a chaniriii;,' dialect ; 
of this history we posse-sd the last volunte alone, relat- 
ing: only to two or three countries. Of this volume, 
,)nly here and there a short chapter has been pre8er\ed ; 
ind of each itaire, only here and there a few liues. 
I'^ch word of the slowly-chaufj^iii^ languag'e, in which 
tlie history is supposed to be written, l)ei!Hf more or 
le-- different in tue in'e.-rupted suicH^Nsion of cliapters, 


maN r.'pri-sent the ai.j.arontly abruptly changeti funrm 
of litV, entoni»K«(l in roti^ntive. but widely 
•fiMirated, formatioiH. < ►n this view, tlu' diffiriiltiM 
alinve dinriiwd .iro trreatly dinnninhod, or even 



( [JAI'J KK X 

I I f K 

i,f"'l (m.i.aI km ( »>.«lu.N Ol. ii,( .A.MC li, .!>«(» 

<l-tf.'nt r,it«-» ..f ,1, 1-,.- .>iM-.i,-. ,.n. «■ l.„t .).. II. .1 Tf»n'-iir 
«.r<ii|« .f «[»■. !.•« fnll.w the name ^. m-ral rul.-i in tJidr :.|i{H^ar 
ati. ,■ aii.l .I11..1; an >|.i mi wif »!«■.!.« un Kitin.ii ,ii- 
On i.itiiiilt.ine..ii» .liiiiuft-* (11 lh«- f.,niii c,f hfr Uir 'lu'liMiit U r 
w. fM (i|, the «tt!!i(tleii ..f rxtliut i-jx-olet t i r%ih •.1!,»t ind [.. 
luii « SI).-. ir» iiii Uic Hint.- ..f ,1. wl..i,rtiH!,t ..f aii.'lriil f.,niui 
Oi, •»,,. iii,-,r^.M .11 c.f tho K.'iiie tNjMB witJilu Ui«- Vf .■ Brea.- 
Siiii;iiiary of i)ri.«-«.|iii(; aihl iii.t.,iit . hapt. r». 

I-Ki us iinw >.n uhftluT tii»> several Jact- .lu-l niies 
rfl.itiiitf t(i tin- tri'oli.j^;ciil Micct'^hioH of oiLMiiio lmiri<8, 
l».'tt.T ac.oi-fl with the roninmn view of the irimiuta- 
l>ilil>c)f specie*, or with I hat of their slow ami ^rradua! 
riio.lifu-alitiii, throutrh (iexeut aii.l natural seleetion. 

Ne\\ >|,e. jes have am>eare<i very slowly. (>!ie atu-r 
another, on the l.ind and m tlie w.-iters. I.yell 
hu-. >ho\\ii il i» li.irdiy jM.^sihle to re>ist theevidetjco 
on tins head in the ease or the several tertiary statres ; 
and every year U-nds to till up the hi ink>' between' 
thetii. and to make the pereent.iire system of lost and 
new forms more ^rnulual. In siune of the most recent 
UmIs, llMdiirh niulouhtedly of hi^rh antiijuity if measured 
by \e.irs, only one or two spi, ies are lost forms, an-! 
only one or two are new form-,, having here aj>|K'ared 
for the first time, either locally, or, aH far as we kno», 
on tilt- ra.f ui tiie earth. if we may trust tiio oliserva- 
tion« of Thilinjd in .'^icily, the suices.sive changes m 
the marine inhihitants of that island have h* 


'een many 

>A^. J^glfaMT /£f 'VH^Sa^' 

«.K»»!.(h;I( AL Sl( ( I-SMON 


Hill riii»t nn" -•■.omljiry format inii« .iri« mor*- 
hrokfii ; Itiit, a« Urnrin lias roniarkrd, ru- thrr thr 
ai>|.".ira!irp n«»r (lis;nij.«'araiu'f of tlipir many im" ••x- 
♦ iii.t s|„Mitw lias l^-t-u Biniiiltntu'oii-* iii »>a«"h wj'iirati- 

>}>««(i»'s of (iiHi'r«'nt ir»'ii«*ni and rla.-o««'s liavc ni.t 
iii.iiiir»M| at the siiriu- rat*-, or in llio Hiinif «l»'»rr«'r In 
the nlilf^t tiTtiary IhmU a f«'v* livini: nhcllH may -till U' 
n»tin.l HI till' mi'dst of a mi]ltitu<le ot extinrt I.Trn* 
K.i!i-..n».r hi-* irwou a '■trikiiij: in-tanir ut a ;t«t. 
Ill .III fxistinif iriMo.liU' a-si..iatr.l with many »traiiu'»' 
and lost niammaU ;<iid n'l.'iU's in the su»v-Ilim.tlayati 
d.-;..wil.H. Hie ^llurian l.iin'ula dirT«'rs but littU- iron' 
U.«' livinir HiHH-ipx of thic lf•Mlu^ ; v*h»Tp»H inont of tl e 
ntl)»'r Silurian Mollii-«»» and all the ( nisfir«'an«» havt- 
» hMijft'd ^'r«Mtly. Tne priHliution- of th«« land mtiu to 
tliainrc ..t a <iuii-ker rat« than thos« ofthe.-ra, ntwhic it 
a strikiiii: iiKtan.c ha.n lately U««»m ohservt'd in Swit/vr- 
luiid 'I'liero i-i -'inu> Ta-oii to helievp that orKain-m-*. 
con!.idered hiu'h in th»^ »«-a1p of nature, rhaiiKe morr 
.|iiii-kly than tho«# that are low : thoiijrh there are ei- 
ceptmns to thi-* rule. I'lie amount of oriranic chaiiife, 
&A I'ittet has remarke^l. doe« not Htrictly corre-jH.ud 
with the surre-ixjon of our ir'^olotrical formations ; ho 
that Wtweeii »-a. h tv»o .(.n-eiutive formation-*, the 
forms of lite have seldom chanired in exactly the same 
detfree. Vet if we compare ariy I'ut the most, clos.dv 
relate.! formatioiiii, all llie -..enes will be found to ha\e 
undertrone some chantre. When a sj>ecie8 has once d'H- 
apwared from the face of the earth, we have reason to 
l)elie\e that the same identical form never reappear*. 
I he stronirest apparent exception to this latter rule, is 
that of the sJvcaHed "colonies" of M. Barrande, which 
intrude for a period in the midst of an older formation 
and then allow the pre-existiii<f fauna to reapjM'ar : but 
I. veil's explanntion, nami-ly, that it \h a case of tciiif)0 
niry mijfration from a distinct treotrraphical province. 
t»et'it>» to nie satistictory. 

Ti cse several factH accord well with my theory. 1 
believe in no tixed law .if rlevelopment, cau-iins: all the 





inlialiit.ints of i country to chaniro abruptly, or simul- 
taripftusly, or to an equal tlevrrcf. 'J'lie process otino'li- 
hcation must he extremely ^low. ITie variahilitv of 
t-ach species is quite iiuiepeiKkMif of that of all others. 
H\ hether wtirh variability he taken advantage of by 
natural selection, and whether tlie variations he accu- 
mulated to a ;;reater or les>er amount, thus causin^f d 
.Tciter or It^sser amount of modification in the varyiut' 
species, depends on many complex coiitinjrencies, — on 
tiie variability lieinjf of a beneficial nature, ou the 
power of inUircrossinj;, on the rate of breeding?, on the 
slowly chan^injf physical conditions of the country, 
and more especially on the nature of the other 
inhai)itant3 with which the varyinj; species comes into 
competition. Hence it is by no means surprising- that 
one >{iecies should retain the same identical form much 
loiurer tlan others ; or, if chansriiiir. that it should 
cliaii:re less. ^V'e see the same fact in ireoirraphical 
distribution; for instance, in the land-.^ie'' and 
coleopterous insects of Madeira having: come to ditTer 
considerably from their nearest allies on the continent 
of Kuro(>e, whereas the marine shells and birds have 
remained unaltered. We can perhaps understand the 
apparently (juicker rate of chancre in terrestrial and 
II more hijjfily or^ranised productions compared with 
marine and lower productions, by the more complex 
relations of the hiirhcr beintjs to their orjfanio and in- 
ortranic conditions of lite, as explained in a former 
chajiter. When many of the inhabitants of a country 
iiave become modified and improved, we can under- 
ftiind, on the principle of competition, and on that of the 
many all-imj-irtant relations of orjranism to organism, 
♦ hat aiiv form which does not become in some dejfree 
TtMiditiod and improved. \r\\\ be lialde to be exter- 
minated. Hence we can see why all the sjKscies in 
the same reiriou do at last, if we look to wide enouirh 
inter vals of tune, l>ecoine nuiditit d ; f(»r those which do 
not chanfje wiU become evtiiut. 

In nieml »'r-. of the s;ime L-Luni the nveraere amount of 
chjuire, di rui;^' lon^ and equal tn'riods of linn?, may, 



(^rha,.s hp rif-arlv ti.e -aine ; but as the r>rr-nnuilation 
ui l..n^-eiidurinL'' (..-Mliterous* ionnatioii> (1.'J>«*ii.1h oil 
^reat masses of sediment haviiitr Wen deposited on 
^reas wlii!.-t sulisidiriif, our formations huve been almost 
.,f*es>arilv afcunuilated at wide and irret:"larly uiter- 
mittcnt iiitrrvaN ; conse<|i]ently the amount ot orjfanir 
.•hai.tre exhibited bv the tos.MU emlu'ddrd in n)n>ecutive 
tormations is not equal. Kach formaUon, on thw vi«w, 
does not mark a new and complete act of creation, but 
.iiilv an oci-a.-ioiial srene, taken r.ltnost at h.ward, in a 
hio^flv chaniriniT drama. 

W V can clearlv understand why i species when one- 
lost should never reappear, even if Lne verv s.ime con 
litious ©f life, or-raMc and iimrtranic, should recur 
For tiiouych the otf-prin^ of" one speties mitrht 1«- 
ndapted (and no doubt this has occurred in inuumer- lustanres) to fill t!ie e::act pla.o of another specie-s 
11 the economy of nature, and thus supplant it; ye', 
the two forms— the ohl and the new— would not be 
identically the s.iine ; for l)Oth would almost certainlv 
inherit ditTereut characters from their distinct pro 
t'enitor.s. For insUnce, it is just possible, if our 
!ant:iil-pii:eons were all destroyed, that fanciers, by 
^triviti^ duriotf lotiir aijes for the same object, niiifbt 
make a new breed hardly di.-tinguishable from our pre- 
sent fantiil ; but if the \areut /ock-piffeon were also 
destroy.'"!, and in nature we have every reasoa to 
I.elieve that the parent- form will generally be suj>- 
planted and exterminated by its improved otfsprinjj, it 
is quite incredible tliat a fan tail, identical with the 
exi^tinp breed, could be raised from any other speciea 
of pigeon, or even from the other well-e.>.tablished races 
of the domestic pijfeon, for the newly-forrned fantail 
would !« almost sure to inherit from its new progenitor 
some slijjht characteristic ditfereiucs. 

(iroups of sj)ecie^<, that is, (reneraaud families, follow 

the same ireneral rules in their api>earance and di*- 

apiK-arance as do >iiii:le si)e<!ies, ohaniCi"K more or ie>« 

luickly. a-id in a ureater or les.cer dejrree. A ^rroup 

due»< r.>t rf-»ppea- after it hau once dixii-peared ; or it« 

^» 1 









f? •!« i 



exiH'.fticp, aH utii^' as it lasts, is rontiiiuous. I .-.i.-. 
iware tliat thort' are Mjine a[>[iarfcnt exceptions to thi? 
rule, l)iU the exceptittiis are siirprisintrlv few, so lew 
tliat K. Ftirl»es, I'lctj^t. and W DodwarW ^houtrh all 
sfroiitrly opitosed to surli views as 1 niaiuuiin) admit itn 
tr'itli ; .'ud the rule strictly ac«'ord> with my theorv. 
lor as all (lie species of the same frr<iiip have desct'udeii 
from sidiH- I. lie sjM'cies, it is cicar thu as lonu as any 
-;>»'<H's ut iiie >froiip have appeared in the lon^ suc- 
I e-- 1)11 of atre>, so Ion:; must its inemtMTs have con- 
tiiitioiisly existed, in order to liave {reuerated eitlier new 
lud inodituMi or the same (dd antl unmodilied furmH. 
^p«'< les of the trenus l.inyula, tor iiisLiince, must have 
<-ontiiiii(nisly existed hy an unhroken succession ot 
uerierations, trmri the Silurian stratum tx) the 
present d;i\ . 

\\'«' havt* seen m lli.' last chapter tliat tiie species of 
a irroup Hometime,s falsely apjH'^r to have come in 
aiiriipti'y ; an.i 1 liave attempted to jfive an explanation 
of this tact, whicii if true would have heen t.iial to mv 
views. Hut sui-h cases are certainly excej>tional ; the 
g-eneral rule heinfr ajrradual increase ni inimU'r, till the 
ifroup readies it« maximum, and then, s<M)ner or later, 
it fzradually If the iiumher of the species of 
a tienus, or tli» uumher of the frenera of a family, he 
represented by a vertical line of varying thicknes:*, 
cros^iiiiT the successive ffeolotrical formations in which 
the species are found, the line will sometimes falsi>lvap 
I>ear to lie^rin at its lower end, not in a sharp point, but 
aliruptly ; it then ^rrulualh thickens ups*ards, some- 
times keepiiiff for a space of et^ual thickness, and 
■iltimately thins out in the upjMir In'd-, marking the 
decrease and final extinction of the species. This 
jfradual increase in numl-er of the tpecies of a group is 
striitly conformable with mv theory ", as the species nt 
the same tj-enus, and the genera of the siime family, can 
increase onlv slowlv and nni.^^ressivelv \ for tlie i)rii<e»is 
of moditication and the production of a numl)er of 
allied tomis must be clow and trradual, - one species 
irivin^' rise first to two «tr three varieties, these bpirig 




kIowIv ronvert»'(l iritu sp«M-ies, which in their tiirTi nn>- 
(iure Vy equally slow st»>i>s nther «*pe<"ie«t, and soon, like 
tlie hninrhiii'JT of a (rrt-it tree from .1 single «teni, till 
tf.f tjrdiip hecoiiia** l.irjfe. 

nn Krnuitxir, i.-W *i li;i\e a^ yet <i>oker. o;i!y itifi- 
'ieiitally of' tiie (li>aj>p«Mraiire of" sjxvio and "t" trroujH 
of siiccif-i. < >n the theory of iiaturnl '^election the ex- 
tiiKtion of oltl forms and the [»r<Mliiction of new atiil im- 
proved forms are iiitiin.iN-ly loniu'fted toirether Ihe 
ohl notion of all the inhahitants of the earth haviiur 
l>een swept awav at successive i>eriod>* hy catastrophes, 
is very general I v iriven up, even hy tiiosc jfeoiosfij*tM, as 
Klie de lU'aumi)nt. Miirclii-son, IJnmnde, etr., whose 
t'C'iieral views would naturally lead them to this con- 
clusion. < )m the contrary, we have every rcisoii to 
'•tlitnc, froHi th»^ study of flie tertiary forniatons, that 
species ,iiid irroups of spf. ics aradually dis;ip].t>ar, on*' 
I'ter another, first from one sp-ot, then from .mother. 
aid finallv from the world. lioth single sjwt us and 
whole irroujM of «pecies last for very unequal periods ; 
some trmujH. as we have seen, havinjr endured from the 
earlie-t known dawn of life to the present d.iy ; tMime 
haviii:; dis;»pp«'ared lK?fore the dose of the pal.eozoic 
peri<»<l. No fixed lav*' seems to determine the lernftl) oi 
rune durinir wlii"h any suiL^le species or any sinirle 
:rtnus endures. I here is rea-son to l>clieve that 
the cotuplete extinction of the species of a trroup is 
treiu'rallv a slower pro<ess han their producti<»n : it the 
appearance and disappt^arance of h jrroup of speiies U- 
rejiresented, as hefV>re. hv a '-ertical line of varvinir 
thici<uess, the line is found to taper more trrad. ally at 
its upper end, wiiich marks the pr<>irress of extermina- 
tion, than at its hiwer end, which marks the first 
appearance and increase in iiumhers of the species. In 
suine case-, however, the extermination of whole j;'rO(i{>s 
of heiutrs, as of ammonites towards the close of tf;e 
secondarv period, iias t^'en wondertuiiy suiiden. 

riie whole suhiect of the extinction of species ha.t 
'<ee?i involved in the mo<*t irratuitous oiv«terv. >ome 



author" li.ivp pvi-n -uppo'^pii tlmt ;»^ 'lio imlividual lian + 
(iofiiiite Ifii^rtli ol life, hh liave Kji»vi#>s a dt'rtiiite dura 
tioii. No ono 1 think can li;ive marvelled more at tl;p 
extinction of sporie", tlian I liavedone. W hen I found 
in I>a Plata the toolh of a liorst* embedded witli the 
remains of Mastodon, Me^atnerium, Toxodon, and 
other extini:t mon^ters, which all coexisted with stil' 
livinj; shells at a very late treoloffical p^'riod. ! wa* filled 
witli astonishment ; for seeini: that the horso, since its 
intro<lu(tion by the Spaniards into South America, has 
run wild over the whole country and has increased in 
nMmi>er« at an unparalleled rate, I nsked myself what 
coiilil M) recently have exterminated tin* former horse 
under conditions of life apparently so favourable. But 
ho'v utterly groundless was my astonishment I Pro- 
f",.^..(,r ( >weii soon perceived that the tooth, though >*n 
like that of the existing horse, belonged to an extinct 
species. Had this horse been still livintr, but in some 
lieirree ran-, no naturalist would have felt the least sur- 
prise at its rarity ; for rarity is the attribute of a vast 
number of species of all classes, in all countries. If 
we ask ourselves why tliis or that sT)ecie.s is rare, we 
answer tliat somethinjf is unfavouraide in its conditions 
of life ; but what that some'liine;' is, we can hardly ever 
tell. On the supposition of the fossil horse still 
in:r as a rare species, we miirht have felt certain from 
the analoiry of all other mninnials, even of the slow- 
iireedini; elephant, and from the history of the natural- 
isation of the domestic horse in South America, that 
under more favourable conditions it would in a very few 
years have stocked the whole continent. Hut we could 
not liave told what the unfavourable conditions wi-re 
whitli checked its increase, whether s(»me one or several 
coiitinjrencies, and at what period of the's life, 
and in what deyree, they severally acted. If the 
<i»nditioiis had gone on, however slowly, becominir 
less and less favourable, we a.ssuredlv should not ha\(' 
perceived the fact, yettlie fossil horse would certainly 
iiave Itecome rarer and rarer, and tinally extinct : — it^" 
place i)eins sci/ed ou by some more successfai competitor. 




It i- most -liffictilt always to rem»'nil»er tliat th« 
increase of every liviriir Uoitif? i« constantly heituf 
checked by unperceived injurious a^'eiu-iej* ; and that 
these same unperieived a^rencies are amply sufficient to 
i-Auwe rarity, and liually extinction. U e see in many 
rases in the more recent tertiary formations, that rarity 
precedes extinction ; and we know tli;it this has heen 
the projrress of events with those animals wh^ch have 
heen exterminat.'d. either locally or wholly, through 
man's agency. I may repeat what 1 published in 184.', 
namely, that to admit that specits »renerally l»ecome 
rare before they become extinct— to feel no surprise at 
the rarity of a s|)ecies, and yet to marvel greatly when 
it ceases* to exiit, iti much tlie same as to admit that 
siokuass in the individual is the forerunner of death — 
to feel no surprise at sickness, but when the fiick man 
dies, U) wonder and to suspect that he died by some 
unknown deed of violence. 

Hie theory of natural selection is jrnninde<l on the 
l»elief that each new variety, and ultimately each new 
species, is produced and maintained by havinp ^ome 
advantage over those with which it comes into com- 
petition ; and the consecjuent extinction of les,s-favoured 
forms almost iiu'vit;ii>ly follows. It is the s,ime wi'h 
our domf>lic productions : wlien a new and slijfhtiy 
imj)roved variety has l>een raised, it at first supplants 
the le>s imi)roved varieties in the same neiirlibourhood ; 
when mucii improved it is tran^^ported far an<l newr, 
like our sliort-iiorn cattle, and takes the place of other 
breeds in other i^untries. Thus the appearance of new 
forms and the disappearatu:e of old forms, both natiir;il 
and artificial, are bound together. In cerUiiii Jiourishiinr 
jfnmps, the numlier of new specific forms which i:ave 
l>een produced within a :riveu time is probably trreater 
tliau that of the old specific forms which have l>een ex- 
terminated ; but we know that the number of species has 
not jrone on indefinitely increasing, at least durinar th" 
later )feo!ofjii-ai periods, so that looking; to later times we 
may l>elieve that the production of new forms has caused 
the extinction ofa^'out tiiC same numl>er of old forms. 




riie competition will trctierally !'♦• ninst sever-'. ;i. 
foriii»*rly exiilained and illii-lr;it»'(| l>y oxaTn|il«»>i, lietwoen' forms which are<t like «'a<h other ui ail re-jpectn. 
Ifenc«^ the improved and niodiricd des(-tii(iaiib> of a 
sj)»M jpi will treiitTally <'ause th»- evtermiiiition of the 
j'.irerit-specit'-' : ami it many new forms have U»eii 
Jevt Inped from any one species, the nearest alliex of 
ti>at ^|•ecie'^, i.f. the sp«M'ies of the 'aino sreniis, will U- 
the n-.ost lial>le to extt-rmination. Ihus. a> ! l>eli»>ve. a 
Munilitr of new species dt^^iended from one sp«'<ii's, tint 
is a new ireniis, c<mieH to supplant an old peruis, helont;- 
Hitf to the same family. Until nvi-t often have hapji'-iied 
tliat a new species l)eloniriiijf to some one cr'>iij> "'''' have 
^.■i/ed on the place occuiiied hy a spfcie** l»eIontrHijr to 
I distinct irroiiT>. ami thus caused its extermiiia'ion ; 
and if iiianv allied forms he develoj)ed from the sin-ces^ 
fill intruder, many will have to yield tlieir places ; and 
it will treneraljv he alliid forms, wliich will suffer 
troT'i some niln'rited inferiority in connnon. liiit 
whether it he species heloniring: to tiie same or to a 
di-tiiict class, which yield tlieir places to other spe«'ies 
wtiicli have heen mnditied and impro\ed, a few of the 
-nfferers may often long^ he nreserved, from heint 
fitted to vonie peculiar line of life, or from inliaintin^ 
some distant ami isolated station, wliere they have 
escaped severe competition. For instance, a sinijle 
species of rriii-onia, a ^reat ireiMJ<< of shells in the 
secon'larv formations, survives in the Australian se;is ; 
■ind a few memhers of the groat anrl almo-t extinct 
LTOiip of (ianoid ti.-hes still inhahit our fre-h wafers. 
I"! TPiore the utter e.xtinction of a irnuiji is trene-ally, 
as >v-, )ia\e seen, a slower process than its produitioti. 

\'» ith respect to the apparently sudden extermina'ion 
• f whole families or ord«'rs, as of 'I'riiohites at the close 
.>f the paheo/uic period and of .\mmonites at the close 
of the secondary period, we nuist rememher what has 
Seen alrea'iv ^aid ')u the nr<ih-'\hle widt» ii'ti"vais of time 
hetween our ccnsecutivc formations ; anu ui these inter 
vals there may have Keen mucli slow extermination. 
Mor''ii,er, vhen hy Hudden immigration or hy unusually 

(;e()Ukjical succession 

Z3i)' H (l«'Vf'lopmcnt, many ':T>«*<"ip« of a in-w trrou}) have 
Ui 'U p<»-.}*c>sion of a new urea, they will have pxter- 
niiiuti'ii in a corresivoTNliiitrly rapifl iiiaiiiier tn.iiiv of the 
old inlial>iL;nits ; ami the forms which thii< yiel<l their 
j>lace^>! '.vill romnuiiily he aUied, for they will partake i>f 
Bome iiiteriority in common. 

Ihus, as it M'enis to me, the manner in which hinjfle 
i«|M'cie>< and whole jfroiips of s[»e4"ies l>ecome extinct, 
acconlx well with the theory of natural Hclection. \\ e 
net'il not marvel at extinction ; if we must marvel, let 
it he at our presumption in imairinin^ for a moment 
that we iiiulerstaiid the many c«m>j»lex contin^'-encies, 
on whii-li the existeme of each sjiecies de|>end«. If we 
for>:et for an instant, that each sjiecies tends to incrcHHe 
inordinately. an<i that «ome check is always in action, 
yet s« Idiiin perceived hy us, the whole economy of 
nature will Ikj utterly ohscured. Whenever we can 
precisely siiy why thi« «i)ecies is more ahuudant in in- 
dividuals than that ; w)iy this species and not another 
can he naturalised in a ^ven country ; then, and tut 
till then, wv may justly t'eel surpri>ed why we cannot 
account for the extinction of this particular species or 
tfroup of speci«'s. 

''n the f'oniui of Lih rfuivijini/ ti/riuu<t tnrnu/taurou«/t/ 
througfmiit the WiirM. — Scarcely any pal*eontolo>;ic,i| 
discovery is more strikinj; tlian the fact, that the forms 
ot lite chanire almost simultanei)usly throujrhout tli" 
uorld. Thus our European ( halk formation can he 
recognised in many distant parts tti the world, und«'r 
the nu»sl different climutes, where not a frairment of tlie 
mineral chalk it.-elf can he found ; namely, in North 
America, in ecjuatorial S«)Uth America, in Tierra del 
Fueifo,at tlie ( aj)eof (Jood Hope, and in the peninsula 
of India. Tor at these distant pointji, the or^rani*! re- 
mains in certain he<ls present an unmistakahle detrree 
of resemhlance to those of the Chalk. It in not that 
the sanu« species are met with ; for in 8ome cAhe« not 
one species is identically the same, hut they lM-U»ne" t<» 
the same families, (genera, and sections of penera, and 




? U 


i ■£.■- 




■ometimcs are Himilarly i-harat-toriM'tl in nurh trifling 
points as nu're sii[»«'rtifial sculjitiir**. Moroover other 
forms, which are not foumi in tlu* ( iialk of Kiir<i|)e, but 
wliirh i)»<ur in thi* tomiationH i-ithtT alxive or h«'h»w, ar« 
Himilarly absent at these <li-tant points of the w(»rlfi. In 
the several su(('e>si\e palieo/.oic formations of llussia, 
Western Kiiro|»e and Nnrth Arr.erira, a similar parallel- 
ism in the fnrm> of life ha^ been observed by several 
authors: so it is, aicordiii:.' to Lyell, with the several 
Kiiropean and North Anieriran tertiary depovit.s. Kven 
if the tew to>-sil species whicli are conuiKiu ti> the ( lid 
and New \\ orlils be i\ept wholly out of view, the fcT^'Jieral 
j»arallfli-in in the siiccessiv4« forms of life, mi the sta^ei 
of the wiilely separated pala-ozoio and tertiary p''rio<ls, 
would still bf mainlest, and the scverrd formations 
rould be easily correlated. 

These observations, however, relate to the marine 
inhabitants of disUmt parts of the world : we ha\e not 
suthcient data to judL'e wht-ther the productions of the 
land and of fre^h water cbati/e at distant pouts in the 
s.ime parallel manner. Wc may doubt wluther thev 
)ia\e thus c)i.ini.'i'd : if the Me;ratherium, .Mylodon, 
.\lacr;iiicheni.i,aiid Toxftdon had been broii^^ht to Kuropti 
trom Li I'laLa, without any informalioii in reirard to 
their treolotrical position, n«» one would have su-pe tod 
tliat thev had co-existed witli still li\ini; sea-> bells ; 
but .In tlie>e inomabtus mon«.ters co-existed with the 
Ma-.todon and Horse, i> mi::iit at least have t)een in- 
ferred that they bad lived durni:; one i»f the later 
tertiary stajres. 

\\ hen the marine forms of life are -pokcn ot as 
havinj; chan^red sinniltaneously throutrhout the world, 
it must not be supposetl that this expression relates to 
the s;iTiie thousmdth or hundred-tliou-andth year, or 
even that it has a very strict ^'Cido-rieal sense ; for if 
all the marine aiiinials which live at the present day in 
Kurope, and all those that live<l in Kurojte durintj the 
pieitftocene period (an enormously remote |>eriod as 
mejwured by years, inidutlintr the whole trlacial epoch), 
were to be compared with those now livin'f in South 

(;K()I,<k;|( AL vSlCTI-XsiON 


AnuT!r,-i or in Atistnili.i, th 

w^onld hard I V \>e .iMe t 

e most skilful iiatumliMt 

i> siv H-hethpr til 

f «»xi«itiji^ or tlip 

|.lei<to,-»'n»' iiilial.itant.suf Kuron.. reM-rnhli-d mostclosol 
'ho-e of tl'O >oMtLt'rn ln-niitiDln'rp. ^n, air.-«:ri. Hevernl 

liiirlily «'r»rii|'i't«'iit oh«ervorH helu've that tl 
[Todur-tinii-t of thf f'lnlj'd >tat«»-i ar»> 
thocp which livrd in Kurojx* d 


nior«'clo«f'y related 
iirinjf rertaiii later 

ertiary >t;iire^. than to tlio^p which now live her. 
it i^ evident that fcwsjliferoim \^i\. 

and if this he 


lores nf North 

depoNifed at the i-re-ent day on the hI ., 

America would herentter he liahle to l»e cli.^<ed with 
M.meuhat older Kiimpean I.e.U. N.vertheless. |,„,kin^ 
to a rernotely future epoch, there cin, I think, he little 

doiiht that all the 

more modern vmrinf i 

namely, the ujiper pliiKeiie, the jdei-t 

niodcrn hed.a.of Knrope, North and ^otith A 

Australia, trot 
nd t 

" cotit.iiiiii^r fo-<i| reniain« in s 


oeene and strictly 

merica. and 

>'u, and Jrom not inclwdintr tho^e f< 

ome (!(• 

only to md in the old 




I are 

er t 

rorrerfiy ranked as siriiiiltani 

mderlyin:,' deposits, would h, 


:n flie al 

If ta( t of the fornis of liff char 

oils in a ueidoL'ieal sen>e. 

itrin^r simiiltaneou-lv 

•ove larire sen-e, at di>tanf p n ts of tl 

IS irreativ struck tho«e ad 

le worl 

de \ 

erneiiil and d'Arch 

adniiralile ohservers, MM 

|>,inille!i«m of the (•airt'o/oio fi 


er referring' to th 

"ornis of life j,, v 


parts of they add, 'If struck hy this stri, 
^.e-iMTic,.. «e t..rn our attentu.n to North' An.erica. and 
tlicre .liMONer a nerie^ ..f anah-i/ous phenomena, it uill 
at ;.ear certain that all nH.diticationM of 

leir extinction, and the introduct 

Sp»'( i(W, 

••ariiKit Ih« ouiiiir t(» 

ion of new ones 

mere changes in niarii 

le ciirrentx 

or other cauM-^ more or l,.s^ loci and fen j orarv l,ut 
df'ix'nd on treneral la«> which -overn the « hole 
K!:.-u.,m. M, I{,,rrande has for. ihle remarks to 
precisely the same effect. It is. indeed, ,,uite futile to 
i'...k to chan:,cs of currents, climate, or other physical 
'■oiKiitions. a- tiie caii>e of the>-e srea* m>''"*=o' '• -•• 
forms of life throuirhout the world,'under 'the 'molt' ,ii'f" 
fereiit climates. \V^ ,„ I'.arrande has remarked 
look to s.»me vp^vial law We .hall >ee thi. more clearl v 




v*hpti wo tri'il (»i Lilt* |irt-i'iil (li-.lrilnitioii of ori,'iMic 
liflin^H, aiui hixl liow slijflit U the relation Ix'tweeii the 
phy-ii'.'il <t»n(liti(iiis of various coutitrie,"*, aud the nature 
of thfir iiihaltitaii!-i. 

Ihis yrt-at fact of thf {»,irallel niiroession of tho fortim 
of life tiiroii;:lioiit the world, is fx|di(ald«* on tlie tlu'ory 
of natural M'lfction. Ni-w s|K'fies are forinfi iiv new 
varieties ari»iiiL', wliicli liave some advanLaj^o over 
older forms ; and tho-e forms, wliieh aro alrea'i\- domi- 
nant, or have some advaiil.iire (»ver tiie oilier /or?ns in 
their own (•(tiintry, would naturally oftenesl ^;ve rise to 
new varieties or mrinient ^pe(•;eH ; for the-e latter must 
Ik; viitoriou- in a still hi^'lier de^rree in order to i>e |ir»'- 
served and to survive. We liave di-tinet evidence t»ii 
;his JKVid, in the jilants whii-li are dominant, that is, 
wliii ii are eommonest in tlieirown homes, and are most 
widely diiiusfd, havini; jtrodueed tlie trreatest niimlH.'r 
ol n»!W Narieties. It is al>.o natural tliat the domi- 
nant, varyiniT, and far-spread injr sptM'ies, whieh already 
liave invadi'il to a certain extent the territories of oilier 
sj>e<ies, should he those whicli nould have the hest 
•liaiire of spread injf still further, and of tfivinjf rise in 
tu'w eountries to new varieties and species. lheproce>«» 
of ditfij-ioii iii.iy often he very slow, heint; depemienl 
on clitiiaLal and ireoifrajthical ciianijes, or on strari;re 
acci<ieiits, hut in the loni; run the dominant form> «ill 
L'eiieially succeed in spre.uliiijf. The ditfusion would, it 
is prohahle, he slower with the terrestrial inhahitants of 
distinct continents tlian with tlie marine inhaldtant- of 
the continuous sea. ^\ e luL'lit therefore expect to find, 
as we aj'parently do find, a less strict liejiree of parailci 
succes-ion in the productions of the lan<l than t)f the«.e.i. 

Dominant siH-'cies sjireadinjr from any reirion mi^irhl 
encounter still more dominant species, and then their 
triumphant course, or even tlioir exi>tpnoe, would 
We know not at all precisely what are all the conditions 
most tavourahle tor the multiplication of new and domi- 

....... ..,..,..;.... i... ...^ ! 41.:.. I. ,l.__i.. _. .1 t 

:;rt;;-. r-Jrc-. :cr, , iruL n c, i ••:!;;:.-, tirilFiV Sff ■ iial a 

numher of individuals, from ^iviiiir a hetter chance of 
the appearance of fa>oiirali!e variations, and that severe 

<.Kn|,<»(,l( AL sr(( F>M(».s 



fnnii»4>tition witli many alrrmly «>xixtinir tori!\j, wtmld U» 
iii:.'liiy t'avoiiraiile. as wnuiil Ik* the [Miwor of' spn-aiiiiiir 
:i.f(i ii'>\v tprrif<irio<». A certain amount (tf iwilntioti. 
r»'nirrinc at lomf intorval-t of titnc, wimlil [irofiaMy he 
.tl-n f'aviMiraiiU', a-* l»«*toro rtplairuMl. ( >im' ijuarfcr ol 
til*' worlil may \n\f* l>«'fri iinwt f'avouraMe for tlu» pro- 
'lin-tinii of iii'w an<l flominanl hpfcies on tli»« lan«l. ami 
arinfl.or for tlin-r in tlu* wattT' of' t}i»> >•«'«. If lwoi:nal 
n-j. ,>!.•* liail Immmi for a lori:; [xtioI favouraMv circum- 
-t in.-ptl in an P(|ual dotrrtv, whonever their iiihahifnnt-; 
met, t[u' liattle wotiM |.c jirf>lon:,'f<l ami m'\»t«'; mil 
-'.m« from oiip l>irthpl,it c ami some from tin- othi-r 
fiiijlt hf victorious. Hut ifi the course nf tim*-, the 
tonus dominant in th« hit:li»'st (Joirroe, wliprpvcr itro- 
diiccd. ivouhi triid <M(>rywhcro to prevail. As tlii'v Mre- 
va^led, they would «auso tlie extinction of other and 
inferior forms; and a,'- tfieso inferior forms would K.> 
allied in croups hy i-iheritance, wliojo >:roups wouM 
teiid slowly to di-an'M-ar ; thoiiirh here and tliere ,- 
- Mtrle mem^^er micht loti;.' I'O enaMed to nurvno. 

I'lius, na it seems to m«>, fh.- parallel, and, taken ir 
iarire »ense, simultaneous, success. on of the same form^ 
ot life throuyhoiit the world, accords well with the prin- 
ciple of now species haviuir heen formed hy dominant 
speci,-.< spreadinjr widely and varyint: ; the iiew species 
tiius i.Tfuiui'^vj heir .^ themselves dominant owifitr to in- 
heritam e, and to havinjj already had Bome advantat'c 
over t!.»'ir parents or over other species; these a:rain 
»preadi;i_'. varyitii:, and firodiicin:: new species. l],t^ 
forms which aro l)eaten and which yield their pla.-es to 
the new and victorious forms, will i^euerally l>e allied iti 
rroiip^, from ii.hentint' >omo inferiority in common ; 
and therefore as new and improved irmups snread 
tiiroujjhout the world, oM eroups will from 
the world ; and the Kuccession of forms in Knt'i wavs 
wii; e\ervv*here tend to correspftnd. 

1 fiere is one other remark connected with this subject 
w: :r;h mak;n^. i i..»vf jfiven my reasons for i>e'iev 
inir that all our lt. ater fo-s'Iiienuis formations were 
de; wited tlur'r.:^ peiiod.s ..f sul.siden.-e ; an<! that 


ON rin: omkwn ok si'K(IF> 

itiaiik iiii**rvai<4 oi vaiit tiiiratioti ocrurrfMi diiriiii; tlie 
p«'rMi(ls mIi«m tlio l»»'<i 'if«» »«'.i w.m oithor HUitiori- 
ary or riHiiii;, and liki't«i««> wlini «(vliriU'iit w.-im iint 
thrown down (jiji»kly etiou^fli to ptntxMl and prenorve 
ofL'^inir r«'tnains. During i1i«"mi lorijf and tilank inter- 
val.- I -'ip|M»>.t« lliat tli« inlialiilaMl"* oi each rtvion 
undnv\)'i.ta i Kii^idcralile amount o( nioditicatioii and 
pxtiiK tmii. and tliat tliere wa-* much mitrration from 
otiuT |>irt-i of' tli«» wori'l Aw wo )ia\»' rca-uti tn 
i>rii»'Vt' that lartT'" aroan are a(r<'<t«»d I'V thf -..iinH nmvt*- 
nitMif. It iH proii.iiil« that Hlricll) coiiTjMnpnranJMtu^ t'or- 
ni.iliMi,, have ofton l»«M»n a<rii'niila!>'ii ov<>r v»<ry -^ido 
•ip.H'tw Ml thf !.afnf I'lartiT ot the world ; hut we ar« 
far fnoii havini; any ri;:ht to roucluile thai this hi- in- 
variaMy Immmi tht» «ax«*. at»d that hir^r areas hav« iii\ari- 
al>i\ 'irtMi at?< rtod hy t}if« same mttv^-mt'ntjH. W li«»n two 
tor !iiatii>ii>t ha\e h«*«'n drpo-iti'd ni •.**.» rfxioii.* dwini; 
n«*arly. loit not exactly tho K.imo p«'riod, we hlionld find 
in liiiifi. from tlie rni>.«'s cxplaiiiwl lu tlu" foreyoin^ ["ara-»> •vinie L'»* suciession in the fiirin«i oi hi-; 
loit tijf «.p<'cit>« would ijot exactly corresjMind ; for liiere 
V* lij lia\ »? Uhmi a little more time in t lie one region than in 
the other tor miniiti. ation, extinction. an>l i mm iteration. 
I >.ii»pect tli.'vt c.i-es of this natiiro (Mciir in Kuro|»^». 
Mr. rrf>t\M> h. in hi^ a<imirahle .MemoirH on the eoi'ene 
.icpovlt.., of l!ii;.'laiid ami Irance, is aide to draw a close 
i.'iMiei il iiara!li'li-m Ix'twecn the Huccossive st^iijeii in the 
two .Kiintrio; hut when ho compare- certain Ktaire** 
in Kiiirlaiid with tlm-e in f-'rance. althcuirh he finds 
in hoth a curious accordance ia the uuiiii)ers of the 
-pecies iH'loiitrin;; to the same tfonera. yet the sj>«»r'es 
tne;iisel\ f- differ in a manner very dithouk to account 
for, con-iderint: the j«.-oximity of the two area-, — unh'ss, 
indeed, it !►« a.— umod that an isthmu- s»'[>araterl two 
-eas iiilialiiled h\ ili.-tiiict, iiut cotitempuraiieous, (auiias. 
L\ell ha-, made similar oli-ervation- lui some of the 
later tertiary t'orMi.iliitns. liarrainie. .ilso, hhowti tint 
thix-e i» a -tnk'iiir irMricrjij rvirjilleli.Ki in fh.e succc«»«ive 
> deposit- of llohcona and ."scandinav ia ; never- 
tlielev- lie find- a -ur[)ri-iii:: amount of diiierentte ia 

(;K(>L(m;i( Ai, Mcc ».si<)\ 






I to 


V* iiie 
I arH 

•* in- 



'.'i ra- 

le re 
II iii 




• 1 •» -|'«'ii»>». If the xevcrul formittioiH iii theM^ reifioiii 
li ivf not Ikm'ii ili'|»<»«jit»'<l iliiriiitf tlie Kiine exact |K>rnMl« 

•a f( 

orm-.tinti III dill' rr;.';(iti ottrii rorre^poiiihinr »i 


.» Iil.iiik iiifiTvil in the otiier,— ami il in Initli rririoim 
flie "-[KMuw h.n" L'"ne on '■lov« I> r!u->nifinjf iluriin; the 
•< ••iiiinii.i'ioii ot \\n' xrMT.ii tortii.itiori-* aii'i iliirintf tin* 


; iiiNTV.iN lit' time lie'.weon tln'in 

in tl 

lis r;i>«- 


^♦»»'r:il tonii.itif'iH in th»" two rrj^ious roiilil U' arr.'ni.'ivl 

111 till' ■..line or liT. in ;i. tiir<l.i/ii«' wi 

11. tl 

le -in- 


m o( tin- liirni of hfe, and tlie orih-r wnnhl faUelv 


to 1 

x'-triitly |i.irall«M ; tn'\«'rti.tMe«*8 the himth'*. 


>♦' tilt' ■siiiie III till' apparciitlv rorre- 

HjMirnlint.' ^taire- m the t.»o nvons 

< '/I ih, Ajfiiiitirx lit I lUiiil >'/ 

«•(>»'.« tit fill 

h iiifi 

tfr, mil 


lu'inii i,.rf'i.s. — \A'\ IIS now look to tlu- nuitnal afFinities 

>f ext 

Uirt .nil 

1 1 

1 \ I n ;: 

I liev all full into one 

Ifratid ii.iiiiral •.y«itiTn ; ami l!ii>. fact is at nnoc rxiilaim'tl 
on (he |irim ijile of (i»'»oont. ilio more amimt aiy 

the inori*, as a cciiiTal rule, it <lit!«T-. from 
living loriii-. Mat, as jlin klanii loiij; atj*) reiiiarknl, all 


»; N ran in- cm- 


>>till exi>tinjf i:ron|»., or 
het«(«on thrill. I hat the extinct forms of liU' In ![> to 
till lip the wile intervals l»etv»een existing: K'enera. taiiii- 
lies, ami onlcr*. cannot he (li»|tut»'il. lor ifw»> conline 
our at'r:it ion either to the living or to the extinct alom>, 
tlie M'r.c« ;s far lens perfect than if wt- comhiiu* hoth 
into nne L'cncral hy'-tem. \V ith re^pt'ct to the \'erU'- 
hrata, «hoIe [Kiires could ho tilled \\,th >trikin;: illustra- 
tion- from oiirirreat palieontolot'i-t, ( iwen, showini; how 
extitu-t aiiinial> fill in hctueen exi-tiiij; >.'roup>. ( u\ ier 
rankt'd tin- Kuniinants and I'ai liyderiii-., as the two most 
di.sliuct orders of niaminals ; hut Owen han discovered 
so nianv fo-.-il links, that he has had to alter the whole 


alion of the>e two order- ; and has placet! certain 
pachyilcrms in the sjime auK-oriirr with ruininantH : for 
f\aiiiplr, he lii.— olves hy tine ;;radalions the apj>arentl\ 

dc llitf 


I'een the iwi^ hiu! thp ivtiiif^! !*■ 
rejard to the liivt-rteiirata, llarramle, and a hi^'her 
authority could not W named, a— crt.- tliat he is every 



ilay t'lii^'ht that Palnxv/oic animal^, though heloriirinif to 
thf' same orders, families, or ;:i'nera witli those livmiT .it 
liie i>reseiit day, were not at this parly epoch limited iii 
Kiicli distinct tr'rniips as they now are. 

Some writer^, liave ohjected to r..'y extinct sjK»ries 
or trroup of species heint,' con>^iilered as intermediate 
hetween livinir species or trr<tup<. if liy this term it is 
meant tliat an extinct form is rlirectly intermciliate in 
all its characters between two livinjr forms, the objec- 
tion is prohahlv \alid. liut I apprehend that in a 
perfectly natural dassifiration many fossil species would 
have to stand hetween livinj; specie^, and some extinct 
trenera hetween livintr e.-nera, even iietween jfenera be- 
hm;ri,,ir to distinct families. Ih.- most common case, 
especiallv witli respect to very <!istinct irroups, such a> 
fish and reptiles, seems to he, Uiat supp<t>inir them to be 
distin^fiiished at tiie present day from each otlier hy a 
dozen characters, the ancient memhers of the same twc. 
•rroujw would l>e distintfuished hy a somewhat lesser of characters, so that the two eronps, though 
formerly ([uito distinct, at that period made some stnnil 
approach to each other. 

It is a common helief that the more ancient a form 
is, hy so much the more it tends to connect hy some of 
its characters trroui)s now widelv separated from ea< h 
other. 'Ihis remark no doiiht must he restricted to 
those ffroups which have undergone much chantre in the 
course of treoloirital atfes ; and it would he difficult to 
prove the truth of tiie })roposition, for every now and 
then even a liviii-r animal, as the Lepidosiren, is dis- 
i-(tvered havint: affinities directed towards very distiuct 
^rroups. Yet if we comyiare the ohler Ileptiles and 
r.atrachians, the older Fish, the older t ephalopod?, and 
the eocene .Mammals, with the more recent members 
of the same classes, we adnnt thut tliere is some 
truth iu the remark. 

litt us ^ee how far these several facts and inferences 
... .1 .1 !• 1 , — 1 — '*^ «,.,.i;t;.>nf;^.r^ 

ill'l'oni **iin tuo i.hi'<'i~y '•' HCM-C. ■• rr..ii :..• -i . .:--n-. .• -.^ 

As the subject is sDmewhat complex, i must refjuest 

the reader to turn to li e dia^^ram ia tlie prelim'tiary. 




\V f may sujuKwe tliat tlie iiiitnhor«sl Iftters n>present 
ifeiiera, and the ilotted Vmo-* <liver:;;n:; from th»'m 
the fijM'iipsi in oadi fftniiis. The diatrram is much t(n> 
-impii', ton few ^renera .iml ton few specie'* l>«'inu: 
tiveii, l>ut ihi-s is uninipDrtarit for us. 'I'he luiri/ontal 
line-; nutv re[>rpsent gucces-sive ffcolotric'il forinatioiis, 
and all the forms hotioath the iijtpermost lino may 
he considered a> extirut. llie tliree cxistintr :r<'iiera, 
''S ?'*? /''*• ^^''^ ^"'""' '' small tamily ; ^'* and / '* a 
closely allied family or suh -family ; and o", f'\ m'*, a 
tliini Vamilv. 'i'iie'^e three families, totrether with the 
many extinct iTenera on tlie several lines of desceiit 
li 'crtrinir from the parent- form (A), will r.irm an 
iinier; for all will have inherite«l .--omctliinir in 
common from their ancient ami common proircnitnr. 
On the principle of the continued tendency to diver- 
gence of character, wliich vva>< formerly illu-tr:it(Ml hy 
fhis diatrrann, the more recent any form is. the more 
r will trenerally ditTer from its ancient prn.jcnitor. 
Hence we can iind<>r-'tand the rule that ii;e mo^l 
.mcient fossils diri^er most from existing; form-. NV e 
mu«!t not, however, assume that divergence of char- 
urtr is a necessary contingency ; it depends solely on 
Uio despiindants from a speci'^s beini? thus enahled to 
seize on many and different places in the economy of 
nature 'I'heretore it is quite posiiihle, a.s we have seen 
in the of some Silurian forms, that a specie- mijrht 
tro on hein^ slifrhtiy moditie^l in relation to its sli-htly 
altere<l conditions of life, and yet retain throughout a 
vast periwl the same general characti^ristics. lliis in 
repre-enled in the diairram hy the letter k'*. 

.\li the many forms, extinct and recent, (iocended 
from <A), make, as hefore remarke«l, one order; and 
this order, from the continue*! ertVi-t« of extinction 
and diverg'ente of character, ha-« Wcome ilivided int*; 
•cveral sub-families and families, some of which are 
supposed to have perished at different periods, and 
cnr'if to have endtjred to the iiresent d;\v. 

Uv loc-kiiiiT at the diairram we can see tliat if many 
of tho extinct forms, sujijxised to lx» emhcd ied in 'he 




\i I 


(,uc.-,es«ive tortnatif.ns werp (liM-ovcrea at spvoral poiiiU 
low .lown in the series, thf three existiiifr lamilies on 
the uppermost line would he rendered less distinct 
from e;u-h other. If. «or in^tan.-e, the irenera a\n\ 
.(I'J n m^ m«, m->, were disinterred, these throe 
tiiuiiies would ho m clo^elv linked totrether that they 
prohahly would have to he united into one trreat family, 
in ne.-irlv the same manner as ha'^ (Kourred with 
rum.niuts and parhv<ierms. Vet he who ohjeeted to 
rail the evtin.t LM'iiera. «liioh thus Iniknl the livmif 
peiiera of three families toirether, interinehate in 
chara.ter, would he justified, a.s they are :nterme 
diate. not dirertlv, hut only hy a lon^' and circuitou-, 

, ,. throuffli m'anv w;:"lv dilTerent forms. If mam 

..xtim-t forms were to he discovered ahove one ot th.- 
■ „i.ldlo horizontal lines or eo.dotrieal for 
,nsU!i<e. ahove No. VI. -hut none Irom thii 
Ime tlien onlv the two families on the lett .lai.'l 
fnarnelv, «'*, etc, and />'«, etc.) would have to U- 
united' into one f.imilv : and the two other tamiliei- 
(iiamelv,^;'* to /'« now inrludlnj; hve trenera. and o 
to mi<)'w..uld vet remain distinct 'Hiese two iamilies, 
however,'d he les« distinct from each other tha.i 
Ihev were hefore the discovery of the tos.siis. M, tor 
instance, we suppose the existing frenera of the two 
families to differ from e.ach other hy a dozen characters, 
in this case the K«nera, at the early period marked \ 1., 
wrMild differ hva les<er numher of character.-; foi at 
this oarlv stii-e of descent they have not diverged in 
character from the .vommon progenitor of the order, 
nearly ^o much as thev suhse.|uently diverged. I hu.« 
It conies thai, ancient and extinct genera are often m 
Pome slijhi detrree intermediate in character hetween 
♦heir mod'ued de-con<lant^, or hetween their coUat.-rai 

' *" hinature the ra-e will \^e far T.iore complicated than 
u, represented in the di;itfram ; h;r the jrroups^wiU 

liave i n more numerous, they w.ii navo c:iu;;rr<; u^r 

extremely une.iual len-ths of time, and will have heen 
rno.litied in various de-rees. /\s we ikj.-^nss only the 



la>r volume of the peoloirical record, and that iu a very 
broken condition, we have no ri^ht to expect, except 
in very rare cii.M<s, to till up wide interval» in the 
natural syHteni, and thus unite distinct families or 
orders. All that we have a ri^ht to exjKH-t, is that 
those irr<)iiji>, wliiili have within known tfeolotrical 
periods UMd»'r>^()iie much modification, should in the 
older formations make some flight approach to ea«h 
other; so that the oldor menilnTS should differ le^'* 
from each other in some of their characters than do 
the existing members of the same ffroups ; and this hy 
the concurrent evidence of our i>est pal»ontolo«-i-- 
seems fre<;uently to l* ilie Ciise. 

Thus, 'til the theory of descent with modification, tii^ 
main f" ts with respect to the mutual affinities of the 
extinct uirms of lif« lo each other and to livirijf forrn-^, 
seem to me explaine<l in a satisfactory manner. And 
lliey are wholly inexj)lic^ihle oi; any other view. 

On this same theory, it is evident that the fauna i)t 
any ijreat j)eri<»d iu the earth's history will he inter 
mediate iu jr«i»eral character between that which pre- 
ceded anil that which succeeded it ITius, the 8|>eci»'.- 
\ 'ich lived at the sixtii >;reat sta^e of descent in tlie 
diairram are the modified ulf>prinf( of those which lived 
at thf fifth sla«e, and are the parents of those whicii 
l)©camt' ^tiIl more modified at the seventh sta^e ; hence 
they could hardly fail to be nearly intermediate in 
character between the forms of life above and Ik'Iow. 
\^'e must, however, allow for the entire extinction ot 
some j.recediujf forms, and in any one region for tli*- 
immitrration of new forms from other re^ous, and n.r 
a lariTf amount of modification, during the long: a'..i 
blank intervals between the »uciessive fitrmalinni. 
Subject to these allowancen, the fauna of eA<-h ue<v 
lotri'al [leriod undoubtedly is iiilerinediate in cliar- 
acter. Iwitween the preceding: and sucreedinjf fauiia.'^. 
I nt'cd cfive only one instance, namely, the manner iu 
which tb.e fn«sils of the Devonian system, when thia 
system was firiit discovered, were at once recog-ni^ed by 
paln'ontologists as intermediate in character liotwe^ n 





those of tlie overlying oirlirtiiiicrous, and uriflerlviiig 
Silurian system. Hut c.ich faiiiia is* not necessarily 
ex.utly intermediate, as uneijual intervals of time liave 
elapsed hetween (-((nsecutive formations. 

It in no real objection to the truth of the statement, 
that the fauna of each period as a whole is nearly 
intermediate in character hetweea the precedina^ and 
ucceedinij faunas, that certain irenera otfer exceptions 
to the rule. For instance, mastodons and elephants, 
when arraii^fed hy Dr. Falconer in two series, first 
accordiny: to their mutual affinities and then acconlinj? 
to their periods of existence, do not accord in arrantri'- 
ment. Hie species extreme in chamcter are not the 
oldest, or the most recent ; nor are those which are 
intermediate in character, intermediate in ajfe. Hut 
sup[ioMnjf for an instant, in this and other such ca.se9, 
♦hat tlie record of llie first appearance and disappear- 
iiice of the species was perfect, we have no reason to 
helieve that forms successively produced necessarily 
endure lor correspon<linif l(«n:rths of time : a very 
ancient form niiL'ht occasionally last much lonjjer tliai'i 
a form elsewhere subsequently produced, especially in 
the ca>e of terrestrial productions inhahitine: separated 
districts. To compare small thinps with ^^reat : if the 
principal living and extinct races of the domestic 
piijeoii were arranired as well as they could be in 
•<erial affinity, tliis arraiiiioment would not closely 
accord with the order in tinio of their production, 
and still less with the order of their disappearance ; 
for the parent rock-piijeon now lives; and many 
v:iriet;os between tlje rock-pia^eon and the carrier have 
I), come extinct ; and carriers which are extrtme in 
the important character of length of beak orig^inatcd 
earlier than short-beaked tumblers, which are at the 
oppo>ltp end of the series in tliis same respect. 

Closely connected witli the statement, that the 
ori^nic remains from an intermediate formation are 
III some decree intermediate in character, id tiie t:ict, 
iusiste<l on by all p.-ua-ontolo^qstiii, that fossils from two 
consecutive format ion- are far more clo*<e!v related to 



each other, than are the fo*sih from two remote forinri- 
tions. Piftet ifivea an a well- known insUmce, tl't- 
fjeneral resemblance of the organic remains from tlie 
Kevoral stamen of the Chalk formation, thoujfh thr 
s;>e<'ics are distinct in each sUi^e, Iliis fact aloin-. 
from its generality, seems to have sliaken Professor 
I'ictet in his tirin lielief in the immutability of specuw. 
ile who is acquainted with tlie distribution of existiiitr 
sj>ecies over the *clo'»<^, ^^'^ not attempt to account to; 
tiie close resemblance of tlie distinct species in closely 
consecutive f>vrmat'ons, by tlie physical conditions of 
the ancient areas having remained nearly the same 
Let it be remembered that the forms of life, at 
those inhabiting the sea. have chan)re<l alnjost simul- 
Umeously throughout the world, and therefore under 
ihe most different cliniates and conditions. Consider 
the prodigious vicissitudes of climate during the pleisto 
leue period, wliich includes the wlude glacial period. 
;ind note how little the s|)ecific forms of the iuhabiunt- 
of the sea have been ath'cte<l. 

Ou tlie theory of descent, the full meaning of the 
lact of fossil remains from closely consecutive forma- 
tions, though :auked as distinct species, being closeK 
related, is obvious. As the arcumulation of eacJi 
formation has often l)eeu interrupted, and as lent' 
blank intervals have intervened between successive 
formations, we ought not to ex|>ect to find, as I 
att'mpti'd to show in the last cliapter, in .iny one or 
two formations all the intermodiate varieties In-twoen 
the species which apj)eared at the commencement and 
close of these periods ; but we ought to tind after 
intervals, very long as red by years, but onlv 
moderately long as measured geologically, closelv 
allied forms, or, as they have been called by'e 
author-., renre-sentative spe, iei<; and these we ;ts.suredly 
do tiii.l. U'e find, iu short, such evidence of tlie slow 
and scarcely se:Lsible mutation of speciiic forms, aa we 
have a just n,;?ht to expect to find. 

On the state of Uetielopnunt of Anci<»i /■'omwr.- -There 


ha- been much discusfiion wh»'ther recent forms are 
more hitfhlv devrlopfd than ancient. I will not here 
enter on this sul.ject, for naturalists have not as yet 
drfui.'rt to each othcr'n satisfaction what is meant by 
hi-'h an.l low forms. 'Hie best definition prot-aMy \?, 
that the hi^'her forms have their orjrans more dislinct.y 
cpecialised for ditfereut functions; and hs such division 
of idu- .loiri»al lalM.ur scrns to b- an advant.-ure to 
each beintr. natural selection will cnstantly tend in »o 
far to make tlie later and more moditi.d forms hitfber 
Ihan their early prot:enitr)rs, or than the sli;rbtly 
modified descendantw of such proijenitors. In a more 
general sense the more recent forms tnust, on mv 
theory, be hi^rher than the more ancient ; for each 
new «iM'<-i'''* 'S f<'""<''l by haviiit: had some advanta^fe 
in thestrutr^le f<.r life over other and preceduiir forms. 
If under a nearly similar climate, the eocene inhabit- 
ant.s of one .piarter of the world were put into com- 
petition with the existing' inhabitants of the same or 
8ome other (juarter, the eocene fauna or flora would 
certainly be beaten and exterminated ; as would a 
M-condarv f.uiiia by an eocene, and a pabeozoic fauna 
bv a secondary fauna. I do not doubt that this 
n'rocess of impruvenuMit has affected m a marked and 
sensible manner the ortranisation of the more recent 
and victorious forms of life, in comj-anscm with th.- 
mcient and beaten forms; but 1 can see no way c-t 
testintf tliis sort of pm^rress. Crustaceans, ft.r in- 
stance, not the hiL'best in their own class, may have 
beaten the hiL'best molluscs. From the extra-^rdinary 
manner in winch Kumpean productions have recently 
-priad over New Zealand, and have seized on places 
«hich must have been previously occupied, we may 
believe, if all the animals an<l plant, of Creal liritairi 
were set free in New Zealand, that in the course of 
Time a multitude of British forms would become 
thoroughly naturalised there, and would exterminate 
many of (hv natives. On the other |::-!id, im^-^-- w.'^- 
we <ee now occurrinsf in New /ealainl, and fn.i.i 
hardly a sin^-le inhabitant of the southern hemisphere 



}.t\iii>< become wild in any part of Kiirope, we may 
<l(juKt. if all the priwliictioiis of Zew Zealand were 
«et tree in (Jreat Britain, whether any considerahle 
mimher noiild he ennhled to seize m\ placen now 
o<<-upied hy our native plants and animals. I'ndcr thin 
point of view, tlie productions of (treat IJritain may he 
«^iid to helii^her thanthoseof N«'^ ZeAlatMJ. ^ ft the most 
>'kilful naturalist from an examination of the species <tf 
the two countries could not have foreseen thi- result. 

A^rassiz insists that ancient animal- resemhle to a 
I ertain extent the eml»ryos of recent animals of the 
»ame classes ; or tliat the jfeoloi.ncal 8'.icces>ioti of 
extinct forms is in some detrrce parallel to the eiii!»ryt>- 
hiLHcal d«'\eloprnent of rercnt forms. I must tolfow 
I'Htet, and Miivley in thinkin;): that the trutli of thi^ 
doctrine is very far from proved. Vet I fully exiMM-t to 
see it hereafter confirmed, ;it least in reirard to snl.ordi- 
nat»> t^^rniips, which have hranched otT from eacli other 
witiiin comparatively recent times. For this doctrine 
or .Afrassi/ accords well with the theory of naturaUelec- 
tioii. In a future chapter I sliall attempt to slmw that 
tlie adult differs from it« embryo, owiiiij to variations 
supcrveiiinn' at a not early ag-e, and bein^ inherited at 
a corresjM)ndinir a^e. This process, whilst it leaves 
the emhi-yo almost unaltcn-d, contiiuially adds, itj the 
course '.f successive ^fenerations, more and more diifer- 
ence to the adult 

I'll us the embryo comes to Ui left aa a sort of [licture, 
preserved hy nature, of the ancient and less nioditled 
condition of eiich animal. This view may he true, and 
yet it may never he capaMe of full proof i>eeini,', for 
in-tan. c, that the olde>t known mamrnals, reptiles, and 
li-h strictly beloiiir to their own pro{)cr clas.->es, thoutrli 
<ome of these old forms are in a -li^ht detrree less di>- 
timt from each other than are tiie typic.l members or 
tlie same t.^roups at the pre<etit day, it «..uld he vain to 
look tor animals havinj,'' the connnon enihryoloi.'-ical 
character of the WrtcbratH, until beds far K'ciH'.itb t};*' 
lowest Silurian strata are discovered— a «li.scovery ot 
which the cliance is very ^mall. 


ON rnK oiur.iN or .spe( iKS 



(^i tlw ^uccf-stoon ft/ tilt' aumr Tyju-x viffitu t/ie siimti 
arian, during the lati-r trrtiary perimls. — Mr. ( lift many 
yo^irs .iL''"' hhowed that the fossil maimnals Iroin tlio 
Aiistraliaii caves were closely allied to tlie liviii>f mar- 
siiDials i)t that coutiiu'ut. In South America, a similar 
relationship is manifest, even to an uneducated eye, in 
the trit'^antic pieces of armour like fho>e of tiie artn;i- 
diilo, f(»un(i in several parL> of i-i I'l.ita ; and rrorej;>or 
< )weM \\;\s shown in the most strilvin;; .nanner that nio.-^t 
of the fossil mammals, huried there in such nuiiiher?., 
are relate<i to South A'lu-riian tyiM'> 'W'l^ r<>Iatii)ii- 
nhip is even more clearly s»H'n in tiie wonderful collec- 
tion of fossil huTies made hy .MM. Lund ami ( lausen in 
the caves of Jirazil. 1 was so much impressed witli 
♦;iese facK that I stron^^ly in>i^ted, in ll{.'>i> and lo-l."i, 
nil this "law of the succes-ion of types." — on "thiM 
wonderful relation^liip in tlie srime ('ontinent i)etween 
the dead ami the livinir.' Professor ( )\ven has Kuhse- 
(juently extended the s;ime trenerali<ation to the' of tiie Old NV'orld. \\e see the same law in 
this aiitlior's ions «»f the extinct and pi^n^ntic 
hirds of New Ztaland. W'ti see it al-o in the hirds of 
tiie caves of !'>r;i/.il. .Mr. W Oodward has shown that the 
Kime law holds ^'ood with sea-shells, hut from the wid,- 
distril)ution of mo>t irenera of mollusc^, it is not well 
displayed hy them. Other c^ses could 1h* added, as the 
relation hetween tho extinct and living laiid -shells of 
Madeira ; and hetween the extinct and living hrackish- 
water shells of the Aralo-Casjtian Sea. 

Now what does this remarkalde law of the succession 
of the s;»ine types witjiin the same areas mean"' He 
v\ould l>e a hold man, who after comparint; tiie present 
climate of Australia and of {)arts of South America 
under the s;ime latitude, wouhi attempt to account, on 
the one hand, hy di .simihir jihysiciil condititwis for the 
dissimilarity of the inhahitants of these two continents, 
and, on the otlier haiitl, hy similarity of condition;-, for 
the uniformitv of the s;ime tvpes in eacli durin/r tim 
later tertiary periods. Nor can it he iiretendeti that it 
U au immutiilue law tliat marsujtials should have heen 



rliiRfly or ^lolcly produced in AuHtnilia ; or that K«len- 
Ut.i and other Amerir.iri typcM should have Wen solely 
produnMl in South Anjorica. Tor we know that Kurop.. 
;ri aiK-ieut timcM wan ppoplod hv numerous marsupi.iU ; 
and I have shown in the puhliratioris ahove alluded to,' 
that in America the law of di«trihutiun of terretitrial 
niaininals \v;w formerly ditferent from what it now is. 
Nortli Ameri.-a formerly partook stroritrly of the present 
character of the southern half of the continent ; and 
tlie southern half was formerly more closely allied, than 
It IS at present, to the nortliern lialf. 'in a similar 
manner we know from lalconer and Cautley's di>- 
coveries, that northern India was formerly more closely 
related in its mammals to Africa tlian it is at the pre- 
sent time. Anaiop)us facts could he jfiveii in relation 
to the (Jistrihulion of marine animals. 

< >ii the theory of descent with modification, the jrreat 
law of the lonjrendurinjT, hut not immut^ahle, succession 
of the name types within the same areas, is at once 
explained ; for the inhahitants of each <|uarter of the 
world will ohviously tend to leave in that quarter 
durin- the next succeedinjf period of time, closely 
allied thouifh in some decree modified descetidants. If 
the inhahitants of one continent formerly differed 
jrreatly from those of anotlier continent, so'will their 
modified lescendants still differ in nearly the same 
manner and deijree. But af^er very loiiff intervals 
ot time and after trreat tfeo-raphiwil changes, permit- 
tintr much inter-miirration, the feehler will yiehi 
to the more dominant forms, and there will l,e' no- 
tiurii: inmiutahle in the laws of pas-t and present di^- 

It may l»e aske<l in ridicule, whether I suppose that 
tlie mejratherium and other allied huije monsters live 
left hehind them in South America, the sloth, armadino, 
and ariteater, an their deirencrate «lescendants. This 
cannot for an instant he admitted. 'Ihese hu^-e animah. 

have heoome whiiUv ^ vH'-'f 
Hut in the caves 'of Itra/i'l. t' 

1,.,,._ !..j\ 

o {>n)g-f-ny, 

lere are many extinct 

species which are closely allied in size and'in otl 





rliaracterw to tlie sj»ooios still li\ ins; in Souiii Anierica ; 
and «i«»mc of tlu'^o tos«;ils may Im> tlin artiial |ir(ii:t'iiitorH 
nt liviiiiT ^{>^^it>s. It nui-t not l>«* forL'ottrri that, nti my 
'. Iienrv, all th«» •.|n»ri('>* f»l the sam<'irtMiu>* have <i('st<'riile<l 
from som«' uiu- <{irii<-> ; ««i» that if Hix irt'iiera, t-arii 
liaviiiL' t'iu'ht <]>ecifs, h«' found iii otic ifooloL'nal forma 
tion, aiul in thf next rtUiTCfilinff '"ormalinn there he six 
othfr allieil or ropn'M'ntative jrenera with th<- -^amH 
tiutiilHT of >-[ii'fic», tlirti wo may < (iii<liiile that on!'.- 
iirii' >.[»»Mii'-i of e II h of tlie six ohitT L'^eiiera lia-* left 
iii(Mii:ic<l (le-icentlanfs, conxtitiitiiiLr thf sjv new >jcnera. 
Ttii' other ^eM-n «|>etie>i ot the niil i^t'iiera hive all 
liied (lilt ami liave left no [uoL'eny. Or. whit h would 
nnihiMv hf a far cnmimuier ca-e, two or three '.jieei* > 
of two or tliH'e aloiu> «if the six older ireiiera will hav.* 
hfcii th»' I'irents of the six new ::enera ; the other old 
siteties ami the otlicr whole old treiiera liavinir U'come 
iitterlv extinct. In failiiiL'' orders, viitli the ^ein'ra and 
s|M'(ies deerea-^in:; in numliers, as apparently is the »as«' 
of the Kdentata of South .\meric;i, still fewer trencn* 
aful spei ies will h; iVe left modii'ed hlood descendants. 

Siuiiiiiiinf lit' thr jirrrtulnii) iiitd prfxfut i 'tutjiti-rx. — I 
have attemjited to show that the jreoloirieal record in 
extremely impt'rfe<t ; that «)nly a small portion (d the 
<;lol>t' lias heen jreoloL'ically exploreil with eaie; that 
only certain classes of oriranic heiriirs have heen lartrely 
preserved in a fossil state; that the numher hoth of 
specimeMs and of specie-i, preserved in our museums, is 
ahsolutely as nothing compared with the incalculahle 
nund)er of treneratioiis which must have pa<sfti away 
I'veti duriii;: a sinirle formation; that, ouniir to sul>- 
sideiicp U'in:,' neeessiiry for t^he ac<'umulation of 
fossilifcrous deposits thick enou^'h to re.>-i>-t future 
degradation, enormous intervals i.f time have elap-ed 
hetween the surressive formations ; that there has prcd)- 
ahlv Uhti more extinction durint; the periods of 

elevation, and durintr the latter the record will have 
l>een lexist perfectly kept ; that each siiiirle formation 

tiK(>L(K;i( AL Sl( ( KSMON 


»c.^ net luM'u roiitinijiiii^ly (lepoHitiMl ; tho diir.itidri 
i.t »>,i.h fnrinatinii m, perhaps, sln-rt inrii[Miro<l with th« 
av<T:u:i' ilumtHMi of »<pffifif tonns ; that miirratioti h-i* 
I'laytMl ail irnport-iiit prirt iti the first ,ipp.>ar;iii.-.> of nrw 
•ornis in any ouo arci and loritiatKiii ; widely 
'iiriirintf Mpi'cu'H are thfwe which h:ivi> v.irii'<l rnrwt, ari>l 
la-p ottt'iH'st ifiveti ris. to iii>w sjn'iir.s ; .iid tli.vt v.irif- 
?:!••* hav»^ at first «»(tt'ii h«'ori UmmI. All these catisc" 
faketi conjointly, must li;i\.' ten»itMl to make the tree 
I record extremely imperfect, and will to a !ar:;e 
extent explain why wp do not. find interminahle varie 
t:rs. connectinjf totreth.-r all the extiiid and exi-tin • 
fill!-; of life hy the fin«'st eradiiated stt!'-. 

He who reieits tii»'.e viewi on the nature of the 
/. . hcMcal record, will ri::htly ren-ct my whide theory. 
I or he may ask in vain «hereare liie nwmherle^s tra.i 
- iiiiiial link-* winch must formerly have connected t e 

• li-'elr allied or represpnUitive species, found in ti -• 
se> eral stiire« of the same ijreat formation. I le may di-«- 
i-eiieve in the enormouM intervals of time wh .-h have 
el.ijisod hetween our ronsecutive form.itions ; he may 
overlook how important a part mi:,^ration must have 
i'!i\ed, when the torrn.itions of any one ereat rc«-ion 
aione, as tliat of Kiirope, are considered ; he nia> 
liTire the apparent, but often falsely a|>parent, sudden 

• omin-r in of whole jrroups of s|»ecies. He may ask 
^ iiere are the remains of those infinitely numerous 
orH'anisms which must have existed huuf hetore the 
■Tst hc<l of the Silurian syst»rm was dejxisited ; I can 
iMswer this latter que.stion only hypotlu ticaliy, hy say- 
iii:r that as far as we vau see, where our oceans uow 
extend they have for an enormous period extended, and 
v*tiereour osi-illatiinr continents now stand thev haM- 
stood ever since the Silurian etmrh ; hut that lon^' 
t'cfore that period, the world may h.i\e presented » 
«n illv liitferent aspect ; and that the older continents, 
forrneii of formations older than any krutwn to us, mr.y 
nit<^ ail "lie iu a melamorpiio.sed coiiditiiu!, or may iic 

t>nried under the oce^n. 

J'avsinc from thes«? diffiriilties. all the other 



«'N I UK .>i(;iN OF yi'KMF.s 



le.'iiliii;r t;»rN in p.i!i4>oiit(»I'»iry pet-m to ino dimply i" 
fnlliiw oil llir" tlnM>rv of do-riMit with moditicat on 
throMi^h natural hrh'ction. We «'ari thuH undiTitAiid 
how it if» tlial lu'w >«jii«rip« rom»» in «low|y nnd mirres- 
Hivply ; how ».|)oci«w of fiitffrrrit rl;ixsos do not iiprps- 
K.irilv ch.itiL'** to^rt'thiT, or .it the samp rate, or in the 
- line (iet'r«'i' ; yet in the lonff run that all underiro 
fiio(lifi(Mt i"ii to "Mine pxfiMit. Thp t'xtin<'lif>n of old 
foriiix is th»' almost inevitahlo coii'^eijuenre of tlip |»ro 
dui-tion of new forms. W't^ r.iu iinder«tand why wlon 
a s[ifvie« hast tnuo disappeared it never reappears. 
<Jroiips (if Hpecie- inrrease in numU>rH slowly, and 
endure for une<nial periods of time ; for the proccw* of 
modi;!' ation in neceHnarily slow, and dejiendt on manv 
I'OMipU'x rontinjfencies. ITie dominant (5j>ecie8 of ti<e 
larjrer dominant groups tend to leave many modified 
desreudantH, and thus new suh-^roups and (froups are 
t'ornHMl. Ah these are formed, the s|>eiies of the les- 
vjjforoiiH frroup-i, from their inferiority inherited froni a 
••oinmon pro.rfnitor, tend to become extinct together, 
and to lea\ r no modified offspring on the face of tlie 
earth. Hut the utter eitinrtion of a whole irroup of 
».j>eries mav often i»e a very slow process, from tiie sur- 
vival of a ii'^ descendants, linperiinr in protected and 
isolatefl siluatioiii. W'lien a jrroup has once who.' , dis- 
ap]>eared, it does not reappear; f(»r the link of genera- 
tion has heen hroken. 

We can understand how the spreadinjf of the domi- 
nant forms of life, which are tho<e that oftenest vary, 
will in the lontj run tend to people the world with 
allied, hut modified, descendants ; and tliese will eener- 
allv succeed in takinir the places of tlu^e groups of 
Rf)ecies which are their inferiori in the strug'jfle for 
existence. HcJice, atU'r lois!; intervals of time, tlie 
productions of the world will ajipear to have chanffed 

\\e can understand how it is that all the forms uf 

iiro, .iriCCiii. .iliU rcilT*;cj i::..r*i* i**j^cL.,t . v;:;c ^.a..u 

Bystcin ; for all are connected hy ireneration. We can 
underKtii.d, from the continued ti'iidency to diverireui e 




anuh'r, v. 1 


e more aririeut a form i-, the 


il i."'!i»Tally ditf^TH from thove now li • ug. W h 
aii.i fxtirut formt ut\vJi tend to fih up t.ijm Ih'Iwwm 
t'ii»',ruf lornix, HometiiiijH lileiidinjr two ^roiij<>4 prt^ 
N ioii il y ilasri«-«l AS distinct into one ; but more rodirnonly 
niih hriiitfiTitr them a little closer together. The more 
nil I'tit a form in, th«« more oflt^n, afiparentiy, it dirt- 
pi, i..-. charii terH in some decree intermediate l^etweon 
■rriHipK now di^ti/ict ; for Die more .-uiiient a fjrin in, 
•!.c more nearly it will lie related to, and con-«e<iue'itly 
re- iiil>lp, tJM^ comrimii [)ro<:f>n:tor of trroupi*, since U'- 

■ uiiie wideh diver^renl. Kxtinct forms are sel.lnin 
"lireetly interme<liatt« between existijitr form-* ; but are 

iiterniediate only by a lonjf and circuitous cour-c 
■iiroujfh many extinct and \ery different fomiH. We 
can clearly see why the or^pinic remains of close!, 
itiii-^ei'utive formationn are more cbwely allii-d 
lo e^irh other, tlian are those of remote formation -4 , 
:>>r LJ.e forms are moro closely linked lo;:ether 

y ;,'eneratiou : we can clearly «e«» why the remaino 
»t an intermediate formation are intermediate in 

1 be inhabitant." of each succes ivp j»«riod in tue 

■ ■ rid's history have beaten their i)rede<e.s«orii in thr 
r.ue for iife, and are, in so far, lii4;iM-r in the scale of 
ii.iture; and this may account for tliat vaifue vet iil- 

Icniied sentiment, felt by many palieontolo-'ists, that 

oru'anisiition on the whole has pro^re8se<l. If it should 
ficre.ifter be proved that ancient animals resemble 
*-■> .1 certain extent the embr\o« of more recent 
njiimals of the same class, the f-\ci will be intelli_'ible. 

liio t<uccesHion of the siiiiie tviH'^ of structure within 
tbi! same areas durinjf the Lter frpolot'iciil jw-riodi 
. e.ises to lie mysterious, and is simply expUmied by 

' tieritaiice. 

If then the ^eolo^ieal record lje as imj>erfect as 1 
believe it to be, an.l it may at least be asserted that 
liie It-curd cannot bo pro\e<i t(» Ik? much nuire perfect, 
the main objections to the theory of natural s«-lectiou 
'•■ Toatly ditiiini«h('<l or (ii-i;ip|.ear < Mi th*- aher 




baml. .'ill tlio cliiof laws of j)aIrt'ou'.<)lo^v jilamly ^ro- 
claim, as it neeins to me. that ;i»ffi»'s have l^***!! pro- 
durftd liy oniiiiary iri'iu'rition : old fornix liavinjr iM-en 
8Uji|>'aiit»'d by new and improved forms of l.fe, pro- 
duieci !iy the laws of variation still a* tirnf ar<i,.nd ua, 
and pre-fived by Natural N'loctitm. 



i - 






';K(HiIlAJ»UICAL |i:>TKIHri lu.S 

P7'-ieiitci'.»tri!<uti'>niamic.t bo an-nui.t.-d ("Thy ditTen H' e» In ii1i)m si 
C')nli!i'>n»— liiip' rUiice r,t tiarritra Attiiiity uf it,' iiri"luti' ii 
■tt iiit s.ime loiitiiuMit -Cetitrtavf >nutioii- Mtai;.i >if ili.«|" t ^ai 
hj UidU'/f* ■ t rliiuate and ■ 'f the lev. ! ■ f lUv Und. nu>i by ■ ■< ■ ;i-i' .iial 
!> eaiis -Inspcrsalcluniip' tho Glacial iKTiod co-cxU'nsive wiUi thu 

Ln coiisiiierinjf llio <listr hution of ortraiiic heiiitrs over 
'ho tiu-e i:f the trldbe, the first trreat fact which htriki-jj 
■IS i^, that iH'itlier the similarity nor the dissinularit\ 
of tlio inhahitaiits oi various retfions ran he iu rountcd 
for hy tlieir cliniatal and otiier physical con(litit)'is. < )r 
late, almost every author who has studied the su});t'«'t 
lias comt* to this conclusion. The case of Ariiciica 
»h)nc would almost suthce to prove its truth : lur if we 
exclude the nortlieru parts where the circumsolar land 
'.* ahiio-t continuous, all authors airree tliat one <i! the 
rno>t fundamental divisions in ireo;:rai>iiical distribu- 
tion is tliat Wtween the New and Old \V'<irUis ; yet 
if we travel over the vast American co'ilinent, from 
the central parts of tlie 1 iiite«i States lO its extreme 
soutlieru point, we meet with the most diversified con- 
ditions ; the most humid distru-ts, arid deserts, lofty 
mountiins, crassv ])lains, forests, mar^!;es, lakes, ami 
^reat rivers, under almost every temperature. TLcro 

/ »i J \ I • 

CAillltktC ut 

wliich cannot he paralleled in the New— at least rt-" 


V AH the same s 

pecie.s jreiierallv re«j 


lire : for it if 



a tiH.>t rare ca-t- u. fiii.l a ;.ti.u{, of or-aniMiis confined 
tf.;iMy Miiall spot, liavm- .(.ndition.s [UTuliar in only a 
; '5'',^ .leirret?; for instance, small area^ in tli« (')ld 
Uoria couM !.,. p.Kiite.l out hotter than anv in the 
New Wcrl.l, yet thoe are not inhabited \,y a' peculiar 
fauna or llora. Notvrith.tandintr this [.aralleli^m in tlie 
cotulitions of the Old and New Worlds, }„.w widely 
difieront arc their livirit,' productions ! 

in the southern hemisphere, if we compare lari^H 
tra<ts of land in Australia. South Afru'a, and «e>tern 
N>ulh America, holwc.-n latitude.'^ 2.V and .'IV, we Hhall 
fni.i parti* extremely similar in all tlieir conditions, yet 
It w<.uld not he pos>ihle to point out three ♦annas and 
iumiM more utterly dissimilar. Or :iirain we may com- 
pare the productions of South America south of lat 
.';.V with tlios,> nortli of ^.r, which conse,,„»»ntlv inhabit 
a con>.derahly ditfer-nt .limate, and they will he found 
Hicoinparahly more closely related to eaVh other, than 
they are to tlie productions of Australia or Africa under 
nearly tlie same climate. .\naloi_n>us facts could he 
/-nven witli re>pect U, the inhatutants of the sea. 

A second ^jreat fact which -trike„s us in our ■■eneral 
review is, that harriers of y kind, or ohstacl,.s"to free 
nn^rration, are related in a close and imporUmt manner 
to the diiferences hetween the productions of yariouh 
remons. We see this in the trreat difference of nearly 
all tlie terrestrial productions of the New and Old 
^V orlds, excepting in the northern parts, where the 
land almost joins, and where, under a slightly diiferent 
climate, there miirht lia\e heen tree miirrati'on for the 
northern temperate forms, as there now is for the 
strictly arctic productio!i^. We see the same fact in 
the trreat ditference hetv*een the inhahitants (.f Au.^- 
tral;:i, Africa, and South America under the same lati- 
tude for theso countries are as much isolated 
from each other as is pussil le. On ea»h continent, 
aho, we see the same fact ; tor on the opposite sides of 

...... .,„.. • •■;:^;:;-.;t,..;- . 1 1 i : ; J i i Ui ■' i I - T .'i i i if f S , Uini Ul ^'rOHt 

desertji, and sometimee even of lart;o rivers, we tind production. ; thou-th as mo untaia- chains. 



Ji'mtLs. etc. , are iu> i.n imjiassahle, or liktlv to have 
einiured so lone as u\e oceans separating,' tontiiu-nta, 

tie (iitferenres are very inferior in (ietrree to tho^e 
rtiaractfristic of distinct continent.*. 

I'lirnin^ to the >e:\, we find t}ie same law. .\o two 
;i;arine fauna' are more distinct, with hardiv a tish, 
-!)<11, or crah in common, than tho^e of the eastern 
(lui western shores of South and (eritral Ameri.a ; yet 

iie.-e ereat faunas are separated only hy the narrow, 
li'it impas.s.ihle, isthmu.s of I'anama. \\'e>t\vard of the 
'(,i»res of America, a wide space of open ocean extend.s, 
.vith not an i«-l,irid as a halting-place for emi^rrants ; 
here we have a harrier of anotlier kind, and as soon i.i 
'his is pa.ssed we meet in the ea.stern i-Land.s of the 
I'acitic, vfith anotlier and totally dist:ni-t fauna. So 
•liat iiere three marine faunas raiiye far northward and 
!-(>ulhward, in parallel lines not tar from each other, 
under correspondinir climates; hut from heiriif bepa- 
rated from cich other hy impassahle f>arriers, eithrr 
of land or open sea, they are wholly distinct. ' »n the 
w-iier liand, proceeiiinif still further wt-tw ird fron; the 
•M-iern islands of the tropical [tarla of tiie I'acitic. we 
njcounter no impa.ssahle barriers, and we have ii nu- 
ii..ra!)le ifilands as haltinir-places, or continuous coxstii, 
until after travellinfj over a hemisphere we come to thj 
sli.ifo of Africa ; and over this space we meet with 
no well-defined and di.stinct marine fauna.->. .\lthouffh 
hardly one shell, crah or tisli is common to tlie .ihov»- 
riariied three approximate fairia.s of Kastern and \\'e>tern 
-Xriierica and the eastern Pacific islands, vet manv nsii 
ra!,.'-e from the Pacific into the Indian Ocean, and many 
siiclls are common to the eastern islands of the Pacitic 
and the eastern shores of Africa, nn almo>t exactly meridians of lonfritude. 

.\ third jfreat fact, partly included in the foreirt>in<r 
•-latement-s, is the affinity of the [troductions of the 
same continent or sea, thoutrh the specien themselvea 
are distinct at different points and stations. It n a 
Li« of the widest ^'enerality, and every continent olfen 
ii;:ianien4i>le instarices. Nev«rthele»« tlie nat;,ralipt 




ill I iM'i' niT, tor iiiHL-iiicc. from iii-rtli to south m-ve 
fail>- to ii»> ^tl•li(!k l)y t!it' in:ininT in wliich successive 
cTdiip- of iK'intr-, .-[M't-i'iciUy di^tiM' t, yet clearly n- 
la'i'ti, if|.lir(' f.ich niiiiT. IIh hears from clo-iely 
alluMi, yd (ii^t.nci kind- of hirils, notes nearly similar, 
fiM'i "-ees tlieir iiest^ -iinilariy con>trurte<i, hut not quitL* 
al:ke, uith e::^->. coliiii rt'd in nearly the same inaiiner. 
'I lie jil.tiii- tlie >traits r)f Maj-clian aie mhai'itrti 
hy lUH' -jMvie- nt" Kli'M I American i-tric)i), am! uortli- 
waid the plain-" ot l.i Plata by aii'.the' -.[mt e?, uf thi 
<iine ; eniis ; and not hy a true o~*rich or tiua, Iiko 
tho-e lound in Africa atnl \u-lralia undc- tlie saiiu" 
latitude, (hi tlie~e ^arui- plains of' I^ I'iata, we see 
the lu^outi and hi/iacha, aiiimal> havini: nearly th'- 
vaiue h.ilii;- a< our liare- and ralihit.s and helm _'i!iir t"' 
'Jje ^anie order of Kodents, hut tlicy plainly di-play 
an Anieriian t\]>e oi' structure. We asrend tin- I'dfy 
peaks of the ( ordiiiem ami wo f.nd an alpine -pecie-< 
of hi/.cacha ; we look to the wit<'r<, and we do not find 
the iie.iver or muvk-rat, hut the coypu and i.i[i\ i-ara. 
rodents of the .X-iuTican tvp<'. iiinumeraine ntlicr 
ilist i.i^e^ roiihl lie i:iven. If we look to the i>iands ntf 
tlu' .\ CI lean sliore. liMv\e\er m':ili thev may differ in 
>rP(do';.rai -truclure, llie inhalut.inL-, though they iii.iv 
'>e all peculiar ^pecie>:. are e-.'-entially American. V\ e 
mav look iiack to ]'ast a^M's, a.s vhouii in the last 
' liapter, and we tind American tyi)es then prevalent 
on the .\nierican continent and in the American sea>. 
\\'e ^ee in the^e facts some de»'p orcanic hon<l, pre^ail- 
lUir throuLfhout space and tinu*. over the same are.i-. of 
laud and water, and inde[)endent of their ptiy-;r;i' c(ui- 
ditioiis. Tlie naturalist must feel little curiosity, who 
x nut led to inijuire thi-^ hond is. 

I'his hond, on my theory, i^ simply inheritance, tiiat 
raustf whicii alone, as far as we positively know, pro- 
ducers or;ranisms (|uite like, or, as we see in the cit-^e of 
varietie.-, nearly like each other. Ihe dissimilarity of 

to iiioditication tlirou^^h natural selection, and in a <|uit« 
•u'l.ird.uate de.Tee to tlie direct i.Jluence of d'"tTenl 

i ■&-'{" -'ii'-i 



physical conditions. Tlie dotrn'e of <ii--<ini!larity will 
'ii'iK»n(l on the migration of the more dominant forms 
iJlite from one r»'f.non into another liavintr t'oen t'fftMtod 
vith nutre or lex«i ease, at periotls more or U'.ss romote ; 

>!' thf nature and number of the former immigrants ; 

- ,Ani on tlieir action and reaction, in tlieir mutual 

stniL'>,'i('s fur life; the rehition of ortranism to orj^aiiKm 

heintr. a- I have already often remarked, the most im- 

Iiortaiit lit all relations. Thus tlie hiL'h inij'ortaiwe of 

"'larriiTH comes into jday by checknii: mit{ration; a- 

ioes time for the slow process of modification thrMui:!i 

'latural selection. Widely-raiiirinif sjK'cies, ahoumiiny 

.11 indivjilualrt, which have already triumpln il over man> 

mnpetitors in their own widely-€'xtende<l homes wib 

'lase the best chance of sei/iutr on new phaces, wlien 

"iiev spread into new countries. In their new home 

'Jiev will be exposed to new condilion.-, and will (re 

juently underjfo further modification and improvement ; 

lud thus thev will l>e<'omo still further victorious, an(1 

will jirodiice groups of modifuMl dcscemlanti*. On thi.- 

■ rin. ijde of inheritance with modification, we can 

mderstPiid how it is that sectiouH of <fenera, whole 

cencra, and oven families are confined to the same 

M-e i>, as is so commonly and notoriously the c^•l^e. 

I believe, ;i-s was remarked iu the la.-.t chapter, in no 
law lit iiecessjiry development. .•\> the variability of 
each spec'ies i-« an independent property, and will iie 
'aken advantage of by natural selection, only so tar as 
it profits the individual in its coniplo; strut'trle for 
life. 'O the detrree of moditituitiou m ditTerent specie,* 
will in- no uniform quantity. If, for in•^tance, a niinibtr 
of 'p.'cies, which Ktand in direct competition svilh ea<h 
other, niiiirate in a body into a new and aMervv.inin 
iMdated country, they wiil be little liable to luiMlificA- 
tion ; for neither mitrration nor i^olatJ0n in themsflvet* 
can do iiivthinfT. These principles come into play onlv 
t)y brinjfiny or^nisms into new relations with each other, 

. - 1 . - . 1 ,_.!.__ ! jU il - 

-..•;i; ;:i a io»SM.-f u;:^rct; w;Iji ir.v m. 


ditioiu*. .\d we have seen in the last diaper that >omn 
forms have retained nearly the s.ime character from an 



■ * % 

pi.i»rrmMj-l;. n-niote ifeolotrif .1 ju-rMwl, ^(. certaiii himtirh 
.,..VH M,)_'-..:fM| over v.i'^t ^pace^, and l,;.ve not hetoine 
.Tfatly inodihf.i. 

<>n tlicso viows,it is «l.viou>, tiiat tlie -t-veral species 
'i the saiijt' irt-nns, thoutfli iiiJial.itiritr the distint 
MiarterH of the ?Torl.'. tnu.-t (>ri;rinallv have priut-i-ded 
irmii the s;in.f -our.,-, jis they have desct'iided from the 
xaii.H protreiiitor. In the caw of those species, which 
have under-., rie duriiijr wfioje irwdojfical perHxIn hiit 
Jittle moditicatiuu, there i-^ not niu.h difficulty in lieliev- 
iiitf '1. iL they may have nntrrated iroTn ttie vame re^^ion ; 
tor duriritr the vast pjotfraphic^l and dimatal chau(res 
"h)ch will have 8upervene<l since ancient times, almost 
any amount of miyration i« possihle. l{ut in many other 
c;i.-es, in which we liave reason to helieve that the 8pe<ies 
of a penus nave heen prodmed withui comparatively 
recent times, tliere is {.Teat ditficnlty on this head. It 
IS also obvious tliat the individuals (if the s;ime species, 
t!iouj,'h now inhahitint; distant and isolate.l retrions, must 
have proceeded from one snot, where their parents were 
iirst produced : for, h.s explained in the last chapter, it 
IS incredible that individuals identicallv the same should 
f-v er have l>een produced tliroujrh natural selection from 
;i3renta speciricaliy distinct. 

We are thus brou^'ht to the question whu ii has been 
lar-cly discussed by naturali.^t*-, namely, whether species 
have been created at one or more points ot the earth's 
surface. I'ndoubtedly there are very many ca«efl of 
extreme dith.ulty, in understandini^ how ' the same 
species could po>sibly have migrated from some one 
pouit to the several distant and isolated mdnts, where 
newfound. Neverthele,ss the simplicity of the view that 
each species vras first produced within' a Hin^le repiou 
.■^iptivat^s the mind. He who rejects it, rejectx the 
>>-ru caiuxi of ordinary ^feneration with su!)se.iuent 
miifratioii, and c^lis in the agency of a miracle. It is 
universally admitted, that in most cases tlie area in- 
h..i.iird by a species is continuous ; and when a plant 
or animal inhabits two noints so dist;int fmn. e;»ch 
olh.«r, or ^.th an intervHl of such a ,;i.; .:, thit the 



gj.^co roul'i not \io easil) pa^-od over by tniifratioi;, the 
fact i~i j^ven as something fiiiarkahle aiMi excpplioiial. 
I'lit' ivipacitv 'if mijjTa^''-^ across tlie ^ea is more dis- 
tinctly limit«'<l ill terrestrial mammal^, tlian |>erhaps in 
any other orfranic l>cintrs ; and, accordnsfly, we fiml no 
inexplirahle cai*ftn of the same mammal inhabitiriir "li-^ 
tant puintx of the w(»rhi. No groiniri^t will feel any 
difficulty in such ca«es am (treat liritiiin having heori 
formt'rly united to Kurope, and cnji>ioi|uently possessjrur 
tlio Hame (juadrup<jds. lint if the same '•{►ecics can 
!m» produced at two separate points, why do we not 
tiud a single mammal common to KurnjK? and Auh- 
tralia or ^outh America." The conditions of life are 
nearly the siirne, so that a multitude of European aiiiitiaN 
and plants have U'coine naturali-ed in America and 
Australia ; and gome of the ahorig'inal plants are identi- 
cally the same at these di-tmt points of the northern 
and southern hemispheres: Tiie answer, a* I tielicvc, 
i--. that manitnals have not heen ahle to mii;rat*', whert-a-" 
>;ome plants, from their varied means of disj)erBal, have 
micTatcd across the vast and broken interspace. 'Die 
•rreat and Htrikinff influence which barriers of every kind 
i^.ive had on distriitiition. is ititelli^ible only on tlie view 
ti at the erreat majority of species have Um^tj produced 
oM one side alone, and have not been able to mig-nite to 
tl:" other side. Some few families, many sub-families, 
very wiany genera, and a still greater number of sections 
of jfonera are confined to a single reflrion ; and it has 
l»een observed by several naturalists, tliat the rr.i t 
i>atural (fenera.or those trener.i in which the species are 
n.Dst closely related to each other, are trener^Jly local, 
or coTifined to one area. What a Htran«-e anomaly it 
\^ Mild })e, if, when coinin^j one step lower in the series, 
*>i the individuals of the same species, a directly oppo- 
site rule prevailed ; .ind 8pecie.s were not loi:al, but had 
l»»en produced in two or more distinct ! 

Hence it seems to me, as it haw to many (>tiier 
niturali>ts, tiiat the view of each !«pecie,s bavinif b« er 
produced in one area alone, and liavinj; sulisetjuentlj 
mii,''ral«>d from tliat areA a* far as it>» powers of miirrUion 



31 n 



%ti'i mih'iistotife innlor past ami prf»«f»nt, roiiditinim jht- 
./littod, is tli»» nio-.t jtrohalilp. ' inlouliftMlly m.iiiy < .«-««»?h 
iMTur, in whiili wp r.iruiot explain how tlie saint' spt'iif^ 
(■ould have passed 'Vom r»ne point to the other. l>ul 
the c-«'"irrap!iical and « liati^fes, which have 
certainly occurred within recent L'eolofjical times, must 
have interrupted or rendered discontinuous th« for- 
merly oontinMoiM raiiire of many specie^. ?»o that 
ive are redncd to roiisider u liet her tiie exceptions to 
ontMiuity of rantre are so nuxnerous and of so jrrave a 
nature, that wo outrht to irive up the Iwlief. reiulered 
prohaitle liv eeneral consideration*, that each specie- 
Isa-' heen produced rt'ithin one .ar"ri. and has mi^'rated 
thence as far as it cimiM. It would Im» hopele-.-;ly lediou« 
to discusH all the exceptional «a>es of the same ^pi-cies, 
no»\ liviiiiT at distant and separated points ; nor do I 
for a moment jiretend that any explanation could In.- 
offered of t mv such eases. But after some nreliminary 
remarks, 1 will discuss a fevr of the most strikiiit elassas 
of facts ; namely, the existence of the same species on 
the summits of distant mounttin-rantjes, and at distant 
points in tiie arctic and antarctic retrions ; and secondly 
(in the followinc: chapter), the wide distribution of fresh- 
water productions ; and thirdly, the occurreiu e of tiie 
same terrestrial vp«>«Mes on i-lands and on the mainland, 
thourrh separateil hy hundred- of miles of open seA. If 
the existence of the same species at distant and isolated 
pointii of the earth's surface, can in many instances he 
expl. lined on the view of each species having'' mitrratetl 
from a sinjfle hirtliplare ; then, considerintr our itrnor- 
aiii e with respect U) former climatal and treotrraphical 
ciiaiii^^es and various occasiotial means of transport, the 
belief that this lias IwH'n tho univer!>il law, seems to me 
incumparahly the safest. 

In discussing this suhject, we shall he enabled at the 
fcame time to consider a point e<iually important for u.-, 
namely, whether the several distinct species of a grenus, 
which on mv theory have all descended from a common 
protrenitor, can have mitrrated (under^oinff modificatioTi 
duriiii^ Bonio part of their miffration) from tlio an'.a 

(;K(K;|IAI'HI( Af. DIMIUlif tion 


uitial'ited liy their {irnir«'iiitor. If it i-aii l>«» -Iuhtji Vi 

'.♦> aliiHot iii\ ari.'ihly tin- r^-c, ;v rcj-iitii, nt' .»liirii 

niD^l -fits itih.i'.ijtaiit^ .ire rlo-.-lv roIat^Ml to, or lx>li>rig 

■(» tlif •i.-inio ireiitT.i wift tlio »ip»Ti(>-. ofa -«•( ond r«':.'iu!i, 

'i.i< prolialil V rfifivt'd nt ^oiiic furnuT [i»Titnl imtni'..T:iiit.-' 

'"rtirn this i>tli«>r roirioii, my thfury will ho -tnMiL'tlitMt'd . 

for \t> laii rli-.irly iimlprstrintl. on the priin'i[il(» ■•' 

nHnlitir:it;on, why th»* iiihahitarit'. < f ,i rciT^on ^ho'il'l >iO 

.'latod to those of aiiofhcr r«':r:<»M, wlirii' <» it h:i- l-t'ii 

-■o. l\«'il. A vohanir i-land, for instamo, iijdi<':i\>*d .r.d 

nrnu'd al thodi-tuiro of ;i t'«'w hundreds of iii;li'» fmr-i \ 

"Mtiiii'ht, would jirohatily n'ceivo fr4im it in t!n' > mi «> 

'• time a ffw <u!oni>ts, and thoir dc-cendants, thou, li 

nodifipd. wo'iid -Mil }»o plainly relaffd hv irihoritanr«» ti. 

;l," inhahit-mts of tlio contiiuMit. ' a-»'-i of this natiir»* 

Tf rornnion, and art-, as we si, ill hi'mifor rnoro full/ 

-• ••, iii»'xplirahl(« on 'lie thonrv of iifh'jtt'iidt'ct in-atinn 

! !iis v\,'\v of till' rrl ition <;f -[mm us im ont- rt-^ncn to 

tiiO~«" 111 anntluT, doc-, not dijTfr rnindi (l>v siih^tit itinjf 

•hi- ^^nrd varii-ty for sjH'cip<j) fnrn that l.-tplv adv.mfed 

n an itiir»'nious papfr !py Mr. ^^ .iila»<',in wliicli he I'on- 

Imit's, that 'every sppt-jp.s has come into existence 

(•.'inrideiit hotli in s[ ,ne atid time with a j<r»>-«'xi-tinii 

■ i'lsidy allied specie*. And I now know from corre- 

s]Hindence, that tliis coincidence he attrihiite* to trctu-fa- 

iiori with modilicatinn. 

I h" prtnio'iv remarks on ' sincrl,. and mi;!t;j>> 
•■litre- of creation' lio not d t!v hear on amUher 
illii'd (|iiestioii, — namely •<* iiether all the individuiil- ot 
•tie same s|K'<-ies have desi eniled from a siriijle ["ir, 
or -iritrle hiTrnaphrodite, or whether, as some aii'horx 
' ippose, from many individuaLs Kirmiltaneonslv cre.ited. 
U itli those or;ranic l>eiiii:= wliich never intercio-s (if 
-will exist), the speiies, «m my tlieory, must ha\e d«^ 
-' •Tided from a sticcession of improved varieties, which 
Alii never have hlerided with other itidiv idiials or vari«^ 
tii's. hut w'ill hrtvg Buoolnnt.v! each other t ^o th..'it. .'it tvih 
successive suuT'^ of modilication and inqirovemeiit. all 
the individuals if eacl< variety will liavc dest^endeti from 
a si!>;jh^ parent Hut \-> ♦be maio-itv of ^-aws, r-in*^!., 

f'^ nl 






w th -jll orjr.inixniH wliicli hahitually unite for i-acli 
('Till, or wl ich of't»'ri iiit«»rcr«HH, I l)«>liov»» that (linitijf 
tliR slow ir.Mfs.s of modifnation the imlividual-t of the 
• [..xKw will have lK>f>ii k»'i»t iM'arly niiiform l.y iuU-r- 
(•r'w«iiitr ; so that many in(i:\ iiluain will have cone on 
"itniiltaiK'oa.^ly cliaiiirinj;, and the whole amount of 
ni'i.lili. ai:..r: will not havf heeu due, at earb ^f.iiff, to 
<ip.>. <'nt from a ^irlt'l(• j>arent. I'o ill nitrate what I : our Kii^^lish nu-o-horsos dilfcr slijjhtly from the 
hor-eif of every other hreed ; hut they do not owe tlu-ir 
difforeiic-e and sujMTiority to des«-«-nt from any Hintrlp 
I'u r, tint to . continued care in Ki;le<ting and Irainiiitf 
iii.iin individuals during many ironeration«*. 

i'M'tore disru-sin^ the three' < l.tssex of fartit, whi.h I 
have >elerted as presejitiiig thetrreafest amount of diJJi 
«'Mlty on tlif theory of ' si ntrle centres of creation,' I 
niiihf s.iv a tew words on the iiMVins of dispersal. 

Mfdiix of J)i.'t>rr.yaL- Sir ( '. Lyell and other autliors 
h.ive ahly treated this suhject. I can ^^ive liere only 
the hriefe-t ai»stract of the more imporUmt facts'. 
( haiitre of climate must tiave had a powerful influence 
mi mitrration : a rc:rion when it.s climate was different 
may have heen a hitrh road for mitrration, but now he 
iiH|i,issahlc; I shall, however, jiresetitly have to discus* 
this branch of the subject iti some detail. ( h.miref" 
of le^el in the latid must also have heen hitfhly .nfiu- 
ential : a narrow isthmus now sej)arates two marine 
fiunas ; s,,hmer/e it, or let it formerly have heen 
siihmer^red. and the two will now J)lond or mny 
!'>rmerly have blended : where the sea now extends, 
land may at a former period have connected islands 
or posvildy even cotitineuts tofirether, and thus have 
allowed terrestrial productiotis to pass frotn one to the 
other. No treolotrist will dispute that mutations 
of level have occurred within the period of existinif 
oreanisms. Kdward I'orbes insisted that all the islands 
in tiie Atlantic must recetitiy have Deen cotniecfed with 
Kiiroi)e or Afric^i, and Kurope likewise with America. 
Other authors have thus hypothetically Iiridi^n'd over 

(.KCMJKAi'ffK Ai. rusrKiiirnoN 


- .TV (M,.ari. ,-111.1 Ik.v,. iiiiit-.l ;.Iin<Kt .•v,.r\ i,Ii,„l to 
-n... maitilan.l. h i,„j..,.d tl... Hrt'.ini.nts „M<i (.y 
»..rt..-s ;,r« tn l.o tr.Kf.vl, it mu^t I.,. :i.lM.:tt.-.l thai 
-.•r olya Mu-l.- |.l.„..l^ vvhi.l, iKi. not m-.-ntlv 
'■•'■:. iiint.-.l to M..„.. .•niitni.-nt. TIih m.-w ...iIn t)ir 
< ■•.' li.iii knot of til., .li^iwrvil <.tthes.„,ies|)e.i.-< to tli.- 
:■ ■••<i -li-t^iiit point.. ;iri.i rrmo.fs manv a .litririiltv 
■•It to iIh- )..-t of my Mid-n.f'iit «e :i!«."not authorisv,! 
'. .olni.tfin- M„h ,.nonno„. j;,M.^-ntMl,;,..-il rl.anir.-H 
-.Mmm t „. of ,.vi.:i„ir .p,...„.s. It mmtu. to me 

• .It u,. I.av.. aKiimlant evi.leiire of trreat OM-il.'atioi,^ ,., 
•■••>i in our rotiruMMifs; but not of .url, v„,t ••li.ui-.-. 

• 'n.-:r |.o.,tio,i atiW .-xt.Mi.inr,. a- to |,.-.m' iinitr.l thin, 
' -Mn t(,.. re.Ti.t i.tTin.i m mrU nth. r afnl !o tn.. 
-n.Tal !titprN.-nm;r o.-raiii-- i.|;u,,|v. I frr.-lv a.imii 
•MM torrnor .-M^t.-ri.-,. „f ,„anv i^laiwls. ri.o. I.,ine(i 

••■, the .,>a, wlii.h may havp ...rv.-.l ;,„ l.;dti„.r- 

•■ H.- f,,r plants au.l for i,i:.nv anii-ril- .iunn- 

■ --'■atin:i. In f!i.- roral-pro.|Mcmir o.-ari. such ^mv ,-r 

. "Il ar.. now mark.-.t. as 1 l.W.ev... nv of .-..rai 

.^•oll'. .tan.lsn,^ ov.-r th.-rn. \Vh,.n'..v,.r >t is fullv 

•!»i.tte( . as I h.-li,.vo it w:!! som.' d.iv Im-. that 


. ' ^oiin- ii.i\ iif, iriar »mi(i 

-u's has pror».,Ml,..l from a sintrle i.i,thp!a. v, an.] 
■'_■'[ in til.- rour-p ..f tin... ne know s.,;.;,.thiin: 
finite .il.out th». ,„.-ans „f di^trihut:.,,,. w,- .hiU !,♦- 

'•■!-;l to spe. wit!, on the „,rm,.r 

'';"'■'"" ••' '►"■ I'"'.! Mut I ,io no' h..!,Hvo that ,. 

. I -v.-r f„. p:„...,| that vvithtn the n-.-ent p.-n-.l 

•■•nf.n.'nts wn.rh a- now .pnte separate, hav.. I.,-.,. 

■•■ -■ 'iously. or almost ro-,tinuonv! v, unite.! with ea. Ii 

-•-•r anil .mm the many exi<t:n- o.'eanir whuni, 

• '■'■•'I t.i.t.. HI .iNtrihufion. .,„ h as the trreat .li??..r- 

'•■ "1 the marme faunas on th.- oj-po^.t,. .i,lp< „t 

-.-r e.,-r.v eontr.ent.- the .-lo.e relation of " the 

'r:arv inhat.ita!:t> of M-v.-ral lan.L a,.,! even se.u* to 

' '• r preMTjt nihahitant.-. a certain -'" r 

an. ma., an.l ttie .jepth of the sea,-~th 

'.'ree of reiat;(,n 
irii tli. 'iiM.rii>iitir.ri of 

.iicli facts seem t. 

pse am 

. me oppost.,1 to the a/lmiswon of 

iH jreoc-raphiral re\olutio 


IIS withiu liie rpcetit 



ON I UK (UtKJIN <»K >J'K< IK> 

t" I, n- ;irr rin I'^-iUitj'd on '■<.. . ■. .^ itlv^iih cii t. 
tirli"'^ ;iii»l adiiiitb"'! iiv hin iiiany '.•ll(»w(r>. Ihe 
ii.iliiro .iiid r»'l;iti\t' ps n|iortioii^ ni tlir'ifant^ uf 
'►'■rail <• i»latiiN likrii^c hci'ii. to !iif ii|ipo~i-ii U< tue 
Ix-lift «<( tht'ir fortiHT <»irititiiiit\ wiili roritiin'iit.s. Nor 
iloi's tlifir almost iini\ t'r>all', oliMuic ..iiiipo- lori 
ta\«inr til'- ;iiltiii>«» oi. that tlirv art* tli-- >vrri k^ «>• 
■•uiikt't' roiitiiH'iit- ; if tlii'V li.i'i i»ri:;i!ial!v <>.\i-if(| a» 
tiioiinl.i;ii-r'iriL''i'*' <'ii ti.f I.hhI, sotii*- at li'a>l ol tlir 
l^laIl(l- -^oiild have Iu'«mi t<irtiit'<l, liki* ntlit-r nioiiiifam- 
«i)"iinit-, (it trruiiiti', inctainorphu M'lii<t», oM fosHJl- 
ifcroi.K or otiu-r ^ui'ii ro. k>. iii-tta<l o. coiisi-Liiiir >>f 
nuTi' [>]]'.'•* ot volc.iuic iii.ittrr. 

I iM '■ 1111'* >av .1 ti'w v^oril- on m liat arc ca'.Ifil afi 
(U'lit.ii I'll in,, \in\ iiKM-i- projii-rly innrlit !'o railc 
o(T.i>' 'till rin-ari". ot (ii-^trilHi' on. I <hall liiTf 'oiiluit 
iii\-''It'i> jtlant* !n IxitaiiHal uork-, thi- or tliat jilaii 
is ht;ii»'<i lo Wp ill aiiantt'ti for wiilc iii«>t>iiiinat ion ; l»u 
tor trail-port across tlii' ^•'a, tlir tri'' it»*r or U'-s hinlitir- 
may Iw "••ml to In' airno-' wlioll;. nuknovn. I nlil I 
trii'd, with Mr. Ii»'rk<'l»'y's aiii, a ft-w ♦•xporitiu-nts, ii 
«a.« not fvcn ktiown ho* tar Kfcd-i ronid rf>i^t 'lif in- 
jiirion* attio'i oi !.t»a-wat»*r. lo ni\ >.nrp;i<t' I found tha 
uiit ot' H7 kinds, <'4 tj<'''riniia'i d atti»r an itnnicrs iri of 
L'!; da\<, "nid a t«'W Mirvut"*! an iiiiinor-i..n of \'<^~ day 
|-"or > tur. rniftiiM'' sakt' 1 cdiirliy tr:t'd >-niall ^<'i>ds, 
williont tlio rip-'ilt' or fruit; .ind .'is all >! fiie-e -cmk 
in a f«'« di\-, tlu'v coiiM not Ik? tioat« d a- r<»>*s widi 
>parrv of tin- >im, vvln'flitT or not tli«'\ '.mtc .niurcd li\ 
tli<« s;ilt-\*,iii>r. Aflt-rwards 1 tried .somt- iar^'»'r fruitf.. 
tap-iili's. etc.. and M)nie of these lioatcd {<<r a lont 
time. It is Midi kiiowti what a ditferem-r tlure is in (he 
hiio\ aiicy of tT'"'"''! ''iiid sciu-oned liinl»er; a-id it oi-furn-d 
to ino that llood- ti!';;ht «;i.sli do.\n plant« or liramdies, 
and that tin >e inijj;ht lie dried oii tin- hanks, anil then 
l>v a fresh rise in the stre-iin he na-iifd into ihe-ea. 
lience I led to dry >tt'ius am* lirmrhes of 'J I jilanU- 

majoritv sink <ju!<kly, hut soin«' which whilst ^reen 
tlo ited tor a ver\ *hort time, when dred tlonted tnurh 



</ :'.rr , lor »', r:|.4- |i.i/»-i-nii*> ; rn iin'il :.i •»•.-, . 
liiit when «lrit'(i tli»«y (i< for '.»<» iia>,,;iii(l .-illrrw.tnU 
^Ifti plaiif.-l tlicy tr«'rtniii,4ti'il ; iii' ;;ufUH |il,iiii 
*itii rijK' U'rricv. flo.itnl Jur LM .lavn, wiicn dri. J it 
ii»t#'il for V,.'> Ha\>, nii-i the >•«•. .1- altiTwarW- li-mhiii 
'•••I ; »lie riiM" ^ctvl^ of Helo-riajlium sank iti tv*o il.iw 
•lull (irifil tlu'\ for ahovo [nt (li\-.. arnl at', i 
' i'<l- i.'fnn.;iat«'(i, Alti>i:»>t],..r out ot thi' ;«i .In.d 
,.laiit>, 1,; ili.atcd for alxivo :^';i .lays, tiid riornt' ni il 
il fioatj'd for a v»t\ murh lon^'.T j..'ri...|. So lliat i- : ' 
•iT.I iTfrmiiiatnl ail.r an iniriuT-i..n ot 2i; day-, ai^i 
i.>^: plants v%itliriiM' iniiKi.iit not all ;tie ^aIlu• >•}.♦•< i,-- 
•i-i in tiiL- forft'oin-.xj.eriiiijMn; tloalrd, art»'r iM-iiicdri.-ii. 
■ r ilK)ve J;{ da\-. as i'ira.swo rn ly iiiUT aiiytliiinr from 
ili.'-i- sraiify t.nts, ur may .011. ludi" that tli«« ««■,■(!-'. 
,»r>8 plants of lus (ountry niirlit !..• rioatrd l.y -.m 
luricnt- duriiiL' .;; dayx, and would n-taiti tln'ir po'wei oi 
. .■rriiiiiai.ou. In .'ohnston ^ IMiysical Atl.i>, ;li»' avjM/n:f 
I •!«' of the srvcral Atlantic viii'-.Mit.s i- ;;;{ m;l.'> pfT 
■: ••tn (>oino ruricnt.- running at the rat** «if tilt in.ic- 
, ■ r dirniy ; on tlii^ averaire, the -.•♦■ds of ,i,»5 plant.^ 
• ••'ItinirinL' to one counuy rniL'lit 'h« llnat«'<l ,i<to-s :'-J I 
:iiiN'> of v,-a to anotlier fountry ; and « lien -trandt;«l, ii 
i'liiwn to a ta\oiiral.U' sftot dy nu inland ::al.", tli.>\ \vouI(i 

^uif-t'.ju.-ntlv to i.iv t.\pt r incnts, .M. Mar't-n- tr,.-: 
>iiiiiiar Mill'-, ,iit in a much hetler rnaiinrr, foi 1 .■ 
i I ic,.d till' s»'t'«l:' in a 1><>V mi tin- ;utual sea, so that IIm-v 
*rif al'ernaf»'ly v.ft and exposeii to the air iiki- really 
I iiatini.' }daii*>. ]|e tried ";»!{ seeds, ntostlv di'S-r.-n! 
litiiii uiiiie; hut lie «-liose many lav.e fruit** and Iiktvvi«f 
-.H'ds irom j)lant.- «lijeh live'iifir the sea; and tiii» 
■*"uld have favoured tin. avera^re lenylh of their liot.i 
!ion and of their resistance to the injurious action ot t| ■ 
-alt-water. On the other hand he did not previouslv 
dry the piaub. or hranch.". witli *!ic fruit; and ihi-, a> 
we have seen, would have oaii.Hed some of them to hH\e 
: -. ;ti :;;;;rri iuiiti . . i he lesuil >*a.s liiat j; of Jll- 

M-eds Jli.ated for 4:.' day-,, and were then cap.ilde o 
iiiinatioii. Hut I do not douht pl.ints exposei. 

> < 


ii' ' 

IP. ■ 


.Ti4 ON IHK OUKilN OF Si'K(:ih.s 

• o th. vvHv.. wo.1.1 tor a le.s iMUO thau iho^. pr«> 
; . M rum vu.lcMt n.ov.-n.ent a^ n. our »^M-n"> " ^^ 

' r. s ott.M lloat.uu' l.-n.^.-r than ih. s.nall .. 

l.i,.,.r iruus or triiit «-oul(i 

:i:r;;j;:ih^.,J>W...n that ...h ,lan:- ..nera.v haw- 

'"^;r::'.i:";n:vl casionaiW,ra,.,..rt.llnannt,u. 

,., n,.er. Dnti' Umt..r .s thrown up ou "^'^ ;1;'.' J 

M tluw.. in thf in'wlst of the widest u,fau> . au.i 

r: r:," ^ f ho oral-islandK in the I' pro.-ure 

.:f o;thlir tools .d..lvtror;When..:so,dned 

tU.. th.-.e stones beinu' a valuable royal ta. Id 

• ♦. ,, tir.i when irr.'Lni arlv ^hajrtMl ^*tone- 

"" '"•":"■;. i in b^ n t of i'..-S ;.nall 'pan-ols at 

l^.;:;;:':; V. M.uV.M.-los.Miinthnrinter>t,.e. 

>\ 1 1 Aw m - M. VortVrtlv tliat not a iKirticle 

.: „^ ' ' .: „t,i-. »i.." ii..^"i"i-' "" ""• *•"•, ►•""»■""'"* 


man> fa. ts ;bo^^.^_ ^^^ ^^^^ \i„i.,,;,es a.-ross the ore.u,. 
vi". nriv I think "^iteiv :iss,ime that un.ler .u.h 
lr.:-,heir rat. of .U.h, would otYen U, .•> m.le. an 



r ; and some atitlmrs have jrivon a tar 



;it*. I 1 

lave ii('v< T -• 

•in an ii)-itanct' of nutritiou? 


efds [lassiiiiT tlirouirii 

the int«'>itin(*s i 

t a 



1 Heeds of fruit [<;i>< uninjured ti.routrh e\«'ii ♦ 


.iii."'stiv(' uryatiH of a turkey. 

In '"lie <"oiirse ot two 

months, i j.icke-l up in my u'.irden I'J kin({>i of «et'(."^. 
nut of the excrement of small, and these «.-enu'<i 
j)erf.^<-t, .in<i sonu- of them, winch 1 tried, irermiriated 
i'.ut the foilowiiiir "ai-l i" m.'-rf important : the crop^ <.l 
birds do not ^e.Tete trH-otric juire, .iiid do not ni tlio 
least injure, as 1 know l-y tiial, the tr«'rminaii<.n ot 
..(■ods : !iow after a iiird ha> found and de\t»ured a lars.'- 
-upplv of food, It is positively as-erted that all the trr.m. 
.in not |>aK« into the jfizzard for 1- or even IH hoiir-. 
K bird in this interval mitrlit easily he hlown t<. tin- 
distance of 60<) niile*^, and hawks are known to loo!^ 
out forUre<l birds, an<l the <onlent- of their torn crop- 
mitrht tiius readily tret scattered. .Mr. Hrent inform> u.. 
•hat a friend of bis had U) ^ive up flyintr earrier-juceon- 
from Iranre to Kn^l.-uid, as the hawks on the K;ic! -h dwtrovwi ho many on tlieir arrival, ^ome hawk- 
md owln bolt their prey whole, and after an interval 
of from t»«-lve to twenty liours, distforce |>ellets, win. h, 
,is ! know from experimentfl made in the Zooloi.n.a': 
(iardens, include seeds capa;dp of cermination. Sttrnf 
-^•(uW of the oat, wheat, millet, cJinary, hemp, clover. 
Mid t»eet irerm-nated after having tteen from twelve to 
•Hcnty-one hours in tiie stomachs of ditferent birds o) 
l.rey ; «nd two se^nls of l)e*'t ^ew after having: i>e<M, 
•hu- retained for two days and fourteen hours. Kroh 
vvit^T, 1 find, eat B*^i- of many land and watc 
ldant.s : tish are fre<|ueutly devoure<l by birds, and tliii« 
•he seeds mieht l>e transq)orUHl trom pla<-e \o pla<e ' 
tnrted many kuids of Heeds into the st^inno hs ot <ie.i.! 
."i4i. and then jjave their bodie,i 'o tishintr-ea^'les, storks, 
and pelicans; tlie--c birds after an in'erval of rianv 
iiours, either reje^-ted the m eds in |>elletj< or p.i-«'.' in their excrement, and several of the^.- ~»ed- 
retained their jxiwer ot jrerminati«»n. ( erUui .mmjUb, 
loviever, were alway'; killed by tliis prorei-!i. 

1 n 




If if 



3v.- i»N IHK OllKilN OF hPKCIF> 

\llhoii«l' the Kr.iks niiil fe«'t .>i h:r,ls arc u'<-Mer.ill> 
nuit- .-lenM. I -hn* thnt eartli w.-n.,-limes ;ulh.Tes 
to them : m. on.' i.^faiic- I removed twenty-two irnmis 
,.l .irv .Mrtii from one foot of a j>.'irtr..i^'e, 
an.i i„ thisenrth th.^n- ua8 a pel.l.le .|iuto as lartr.' as 
llH, so, (i of a vetch TIhh see<l> mi-l.t oora^:orial!> be 
truisporte.1 to irreat (li>tancPH ; for inanv facts comI.. be 
uiven -l.ouinjT tlwit soil almost everywhere is (-.larfre. 
;. ith M.-e'ls. Hellect for a tn-'ineiit nn the millions o. 
quails which annuallv cross the Me-literrauean . ui.l cai« 
we .l..iiht thai the earth adheriii? to their feel vfou 1.1 
snmetimeM include a few minute seeds .- IJiit i -ha, 
prcsen'lv hav.' to recur to this suhject. 

\s iceher-"* are known to he sometimes .oaded v\!th 
^.-.rth and stones, and haNe even carried t.r.ishwood, 
i.ones. an<l the ne^t of a iaiid-hird, i can hardly. louht 
Ihitthcvmu.t'.cca^ionallv h-ve trar^^ported se.-.Utron. 
«,„ to another of the arctic and antarctic re- ons^^ 
as .'i '^este<l hv l>v»'ll ; and durint; the Glac-al |.erio i 
fron. one i.arl .'.f the now temperate re^'ions to an..lhcr. 
In !lie \/ores, from the lar-_'e number of the species 
ot i.iant.s comm:.n to i:urope, in omparison w,th the 
i.iant.s of other oceanic islands nearer to the mainlanu 
uid (a.s remarked bv Mr. II. (•.\\'at.son) from the some 
vhtMiorthern character nf the flora in comparison witb 
•i.e latitude, 1 susjuvted that those islan-ls had Wei^ 
. -irtiv sto,ked bv ice-borne seeds, dunriir tlic Uiacial 
;.„ At mv request SirC. Lyell wrote to .M. HartuiiK 
u, inquire whether I.e had observed v.rratic boulders 
.,,1 thcM^ Island-., and iie answered that ho had found 
i,rv fnurmeiits of -rauite and other rocks, wh:ch do 
unr.Mcur in the ;.nhipelat:o. Hen-e we m.ay <afely 
inier that iceber^^s fornerlv landed their rocky burthens 
on the chores of ihe>e mid-oceau i-iand-. and it is at 
least possible that they may have hro,i-at thither the 
-iii>d-i of northern plants. 

(•.,..o;.i„ni„„- that til.' several above means of traiiK- 
port,' and that several other means, which witliout 
doubt remain to l>e discovered, have Wen in act.oii 
V ar after vear for renturi.- and l.-us of thousand.s of 



\t'v.-n, it would I think l)e a marvelloui fact if many 

ilan'a had not thus become widely tran-|>orted. IlieM*' 

ii»ian«« of trail-port are sometimes called accirlental, but 

hi>» ix iii)t strirtly corrert : the currents of the nea are 

.ot aaiiU'iital. nor is the direction of prevalent jfaies 

if wiiKt. if should be observed that scarcely any 

iieaiiH (if transport would carry >eeds for very KT<*at 

iistant«<i ; for seeds do not retain tlieir vitality w^hen 

•V posed for a irr»'at leiiirth of time to the action of sea- 

AJiter; nor could they be lonj? carried in the crops or 

,iitefttii,c-iof bird><. 'Hie-e means, however, would sufhce 

'Mr occasional transport acrosH tracts of sea some 

i iiiln'd miles in breadth, or from island t<» island, or 

•r((m a continent toa nei^hhouriiitf '>laiid. but not from 

lie di-tant continent to another. Hm- floras of distant 

ontimuts would not by -uch means become mintrled 

II any ^rreat decree; but would remain as di-;inct 

i-i w»« now see them to be. 'Hie currents, from their 

»ur-e, would never brin? seeds from .Ndrth America 

• Britain, thoujfh they mitrht and (..) bring seeds 
.mil th«» \\'e'-t Indies to our western shores, where, 
: not killed bv so lontr an immersion in salt-water, 
ru'V could not endure our climate. Almost every 
•mV, one or two laud -birds are blown across the 

»l.o!e .Atlantic Ocean, from North America to the 
*t'-tern shores of Ireland and Kiifrland ; but seeds 
11 lid l>e transported by these wanderers (uily by one 
iipans. namely, in dirt stnkitjjf to their feet, which 
- m itself a rare mci.lent. Kven in this case, how 
-rnaii would the chaiu e 1)6 of a seed falliiii,' on favour- 
Me soil, and coiiiin? to maturity! But it would be 
. irreat error to arirue that because a well -stocked 

• i.ti, like (Ireat Hnlain, has not, as fa.' as is known 
uid it would be verv difficult to prove this), received 

vithin the few c»Mituries, throuirh occasional means 
• transport, immiirrants from Kiiroi>e or any other 
itinent, that a poorly-stocked island, thoutrh standint: 
.,.r« rairi'.ite froTp. tht' mainland, would not receive 
.ilouists by similar means. I do not doubt that out of 
'^' ntv -ced-i or r'nimals transported to an island, even 



.... ^^^rs^i^^^ 

! i 



,f f&T loss w<»ll-Ht()rk.(i Uiaii linuiiu, grrinely wnrf ihan 
one would \>f. «•• wfll titttvl to its ih-w homp. a« to 
beiome Il.•lturali^.•(l. Hut this, a». it hwdh t<» rre, i» 
no vali(i ar^runient aiiaiiist what wouM 1h> effocU'd hv 
ocrasictnal tueariK of trans^Kirt, duriiijf the loiitr I:H>«*e "^ 
fc(iIoai< tiirip, whiNt an islatid wa*- h«'in^ ■iplif^vfd 
ami turmrd, ai.d befort" it h.iii l>o<-nmp fully sunrkrd 
with '.iihaiiitaut^s. < >n aimont hare land, witli !♦•* or im 
<iehtru<t)v»» iiij-fcts or hirris liviufir there, n.-arlr e\ery 
»e«'(l, wh:< h cliaucefl lo .irtive, if nited tor ilie clirnau-, 
WDiiliI We nure Xi> jrermiuato .iiid survive. 

[hM>rr*(il dtirMiij ttif iilnriiil prrunt. The iden':'v of 
many |'!aiit> and aiiima!-. on inouiiUiiii-suiiinm.', -'Miar- 
ateii iVniii e;ii ii other hv liuiidred< of mile-; of l(i\»latid:>. 
\Tlicif thfl Alfiiue -.iieiies could not |»o>^silily e\i-:t, i*- 
oiie ot tlie nio>.t striking tasox known of »!<; hanie 
NJ.«•.■ie^ livirit; at di>Uii'. jiointH, witiioiit the a|>pareiit 
j.o'im'.ilit V of their h.iviiiL' mitrrated from one to thn 
other. It is indeed a reinarkahle fa<t to ~<»e ho ma:i\ 
of the Name plants* livinj' on the snowv reirio.i* of 1h<' 
Aijo or I'yreiHM"^, and in the extreme northern pa-ts 
of Kurope ; !>ut it i^ far more lemarkalde, that tlie 
plant.-, on the White Mountani^. in the I nited Sta-«« 
of Aineriea, are all the «ame with tho-e of l-ihradir, 
and nearly all the same, as we hear from A^^a <;ray. 
witii those on the loftiest mounbiins of Kuroy*-'. V.y'U 
ae luiiiT aiTO as 1747, !"i<h faet.s led (ii:ielin to rondude 
that the Kanie spe. les must have heen in<iej)e!identlv 
created a' M«veral distiiu't ponits , and we miirht have 
remained in this fvin e belief, had not At'^assiz and 
others called vivid a tention to the (ilaoial period, 
which, as we shall immediatelv see, afford-. \ -impli 
explanation of these facts. We have eviden- e f)f almost 
every roneeivahle kind, ortranic and inorjranic, that 
vrithni a very recent jfeolotrieal period, central Kurope 
and .S.irth Amerioa suffered under an Arctic climate. 
I iie ruiii'» ol a iioiiSr- i»uriil i>y ure iio noi icw i;;i":« 
tale more plainly, than il(» the mountains of Sc«»tland 
ind W ales, with iheir ..coreii flanks, poli.^hed Hurfjcen. 



ind penciled Injuldprs, of the icy streams with whirh 
rhtir valleys were Utely tilled. So jjreatly lias the 
rliniatf of Fliimpe rhaiitod, that in Northern Italy, 
_M>i;iiitic moraine*!, left by old trlaciers, are now rlotlifd 
}>y the vino and maize. Throughout a larp:e i«art ot 
the liiited States, erratic houlders, aiul rocks score<i 
hy drifted iceiier{rs and ♦ oa«t-icG, plainly reveal a former 
cold jHTiod. 

The former influence of the jrlncial climate on the 
iistrihutidn of the, iiihahitanU? of Kurojw, as explained 
•■ r.-markahle clearness by Kdward Forties, is snl)- 
xTantially as follows. Hut we shall follow the changes 
more re.idilv, !>y supposing a new ^'lacial {>eriod to come 
<lowly on, and theji \t&^< aw.iy, a.s formerly occurre-l 
As the cold came on, an> i- each mi^re suutiierii zone 
'.'.anie fitted for arctic hein:rs and ill-titted for their more temperate inhahitjints, the latter woul"! 
tie supplanted and arctic pr<-(i notions would take the r 
.'aces. The inhahitants of th.> more temperate refrions 
■ould at the same time travel southward, utiles.^ tln^y 
••re stopped !>y harriers, in which case they wculd 
cri-h. I he mounUiins would Jerome covered wilh 
nou- and ice, and t>ieir former Alpine inhahitanN 
^^nuid ri.'-cend to the plains. Hy the time that the 
cuiii had reachp<l it.s maximum, we should have a 
uniform arctic fauna and flora, covering the central 
parts of Kurope, as far south as the Ah» and I'yreneeji, 
and even stretchini; into Spain. 'Hie n<iw temperate 
rf::ions of *he United States would likewise be covereo 
hy antic plant- and .mimals, and these would be nearly 
the same with those of Europe ; for the present circuir 
pulir inhabitants, which we suppose Uj have ever\ wiieir 
lra\e;lfd southward, are remarkably unif<irm round 
the wnrld. \\'e may suppose that tlie Glacial pertod 
>amo on a little earlier or Inter in North America ihan 
n l.iirni.e, m will the southern mifrration there have 
licen a little earlier or later; hut this will make no 

1 . .V « :■■ «1... ('.Lrtl raulllt 

';:::•:';":;•.." : i i •. r : "^ ■ ■ :i t» t • * ■ — - . . - 

A«i the warmth returned, the arctic forms would 
ii-tieal uo'*h«ard. closely followfvl up in thoir retnal 






>iv tlif prorlurtioiiv (it the nutn" tPm|MTat»' retrioii»». 
Anil an tin? miiow nu-ltt'd from tlie bases <»f the tixmii- 
fains, tlie .'irrtic tonus would spi/.e ou tlie «Uare<l aiul 
«h:i'.v»'<l ::roinid, always a'ceiidiiitr hiirher and hi^'lior, 
,v- the warmth iiiiTeased, whilst tlieir lirethren were 
l»'ir'-m"a; their northern jotirtiev. Hence, wlien the 
v^ann h had tiilly returneil, the >^ime aretic speeies. 
.vlii.ti had hitely lived in a l.ody tot;»'tlier on the 
lowl.uids of the Old aii<i New Worlds, would !>e let\ 
isolait d on distant mouiitain-«iimmits ihaviiiir been ex- 
rernmiated on all lesser heiirhts) and in the aretic 
e^ions of hotli heiiiisphere>. 

liiiis we can understand the idenfit\ ot many plants 
,«t poiiius -o ittmiensely reniote as on tiie riuiuntains ot 
tlie I iiit«*d States ami of Kiirope. ^^ e can thus also 
iindersUnd the fact that the Alpine plants of each 
ii.ouiitain-ranirt' are more .'-jtecially related to the 
arctic forma livinir due north or nearly due north o! 
them: for the miuTation as the cold came on, and the 
re-iniLTation on the returnintr warmth, will ^reiierally 
have heeti due smith and nortli. 'Hie Alpine plants, 
lor example, of Scotland, rh remarked l)y Mr. H. (. . 
\\ atsan, and those of the I'yreneea, as remarked by 
Ix.iiiH.ud, are more especially allied to the p!ant« of 
northern Scandinavia; those of the Lniicd >tates to 
l^ahrador ; tho>;o of the mountains of Siberia to the 
arct"- regions of that country. ITieso views, grounded 
as thev are on the perfectly well-ascert;iined (.ccurrence 
of a former (facial period, »;eem to me to evplain in 
-I. satisfactory a manner the present distril)Ution of the 
Alpiiie and Arctic productions of Kunine and America, 
that Hhen in other regions we fnid tne same -pecie- 
.»•! di-lant m«»untaiii-summits, »»> may almost conclude 
.vittiout other evidence, that a colder climate permitte<! 
'heir former micratioM across the low intervening tracts, 
riii«.o bcc«ime too warm for their exi>-tence. 

If the climate, since the Cllacial period, has ever 
rccn in aiiv urrrvrc wafTnrr than at pre^nt '■a- <^r,^^ 
•jeol<.;rist« m the I'nited States believe to have l>een 
'liH case, chietlv from the dist riluitioti of the fossil 



(Mifitlifxlon), tlien the ar<-tu- and tmipenue prodiictiorw 
.vill at a very Lite jK-riod have marohed a littlo further 
lorth, and siih<p»iiipiitlv have retrf-ated to tlieir present 
homes ; hut F have min with no satisfactory evidence 
Aith re««pect to this intercalatr.l .-litir>«tly warmer peri«).l. 
-UM-e the (flacial period. 

The arctic forms, durinir tlieir lontr southfrti inie-r.i- 
tiou and re-mi<rration northward, \m!1 have U"U (><- 
oo-ed to nearly tlie !«»mo climate, and, as i«» especially 
to \*e noticed, they will have kept in a ho<ly totrether ; 
. (.nseqiiently their mutual relations will not have Wcm 
much distur'hed, and, in accordance with the principles 
Kculcated in this volume, they will not have heen 
iahle to much moditicAtion. But with our Ali-me prrv 
hictiuiis, lef\ isolated from the moment of the returiv- 
titf warmth, first •«.t the bases and ultimately on the 
-ummits of the mountains, the ca-e will have heen 
■^onu'^hat different : for it is not likely that all the 
-ime arctic species will have heen left on mountain- 
ran-'cs distant from each other, and have survived there 
over since: thev will, also, in all prohahility ha\e in- 
come mintrled w'ith ancient Alpine species, which must 
ti.ive existed on the mountains before the commence- 
II .-lit of the (llacial epoch, and which during its coldest 
'„ri(Ml will have been temporarily driven down to the 
1 Inns ; they will, also, have been expoHed to som»«wlial 
.different climatal influences. 'ITieir mutual relations 
will thus have been in some decree disturbed ; cons*©- 
.' lently thev will have been liable to modification . 
■md this we find has been the case ; for if we compan' 
the present Alpine planta and animals of the -everal 
i'r(>at KuropeAn mountain-ranees, though very munv 
nf the -pecies are identically the same, some present 
varieties, some are ranked as doubtful forms, and some 
t.'* are distinct yet closely allied or representativ 

species. , 

In illtistratintr what, as 1 l)elieve, nctiially took place 

i , ii:;r the Viiatiai prfiSJU, l aar---!-; — ; r.-.v ^ -_ 

nu-nocmeiit the arctic productions were a« uniform 
-ound the polar regions a« they are at the present day 




I t 


Hut tlirt forH^oiii;; remarks on di-trihiitioii applv ijn? 
only to strictly .irctir toriii'*, Imf ajno to rn.iuy siil>- 
«r<tii- .iiMJ to Home trw iiortluTii tonipprato forms, for 
POTTie (it th»'«p are tlu' Banif* on tlu' l<>wor ninuiitain.a 
and (in the pl.iins of North Anicricj* and Kiir(i|«»' ; and 
it itiav lie rc.i-diialdy a.'^ked ho'v I arcouiit for tin- 
iiwcss;irv li'-LTcc o( uniformity of the Hul>-.'ir<'t;(: and 
nf»rllieru tt'inpcratp forms round tho world, at th( 
romnicnr»»Tni»nt of tiic (ilarial fM»ri<'d. At tlic |>r»'sent 
dny, tli<» sub-arctic and rthprn ti'inperalc |ir(Mjijc- 
ttoiiK ot" tlie Old and New i\'orlds are scparal^'d from 
each oi'hur by the Atlantic ( )cean and by t'no rxtrcmc 
northern part of the f'acific. I>urimjr the (jlacial 
'•••nod, I* hen the inhabit. mtw of the < 'Id and Ne^* 
\\ -i-lii, lived further southward^ than at pri»scnt. thev 
!i)u»' iiave been still more <'imjilet«'lv -e[iarat<'d by 
•vider >^;>'ue>< of ocean I l>elie\c the alio\e dit?i<uhv 
may be -urmount4»d liy lookintr to still earlier diatiircH 
of clim lie of ati o|i|Hisite nature. ^V^• have trood reaMin 
'o believe tlat duriiij; the ne'ver i'iiocene period, he 
fore 'lie <ilacial p|»och, and »'iil»t tlie niaiontv oi the 
Tib kbitan!.>< of th(> world -"ere s|iecificallv the ^*ame 
1,-1 no-.v. the climate was warmer tlian at tlie present 
day. Hence we may "-iippose that tlie ortraniem-; now 
livintr under the (limate of latitude t50\ durintr the 
I'iiocene period lived further north under the Polar 
t irdo, in latitude *]i\"-iu' '. and that the strictly arctic 
productions then lived on the broken land ntill i:earer 
*o the pole. N^^v if we look it a (flobe, we shall see 
that undiM the i'olar ' irde there is almost continuou.s fr(mi western Kurope, throuirh >i!ieria, to ea.-- tern 
Allien.. I. .And to this continuity of the circumpolar 
land, and to the ronse(|uent freedom for intermitra 
tioii under a more favourable cliinnte, I attribute the 
neco-^iry amount of uniformity in the sul>-arctic and 
northern teiiiperato [(nxiijetions of the < 'Id and New 
\\ drills, at a period anterior to the (ilacial epoch. 

fieiievinff. from rivLsous betore aiJudeti to. thai our 
continents have lonj; remained in nearly tlie s;ime 
relative i>osition, thoui:h subjected to larjfe. but partial 

I I 


(;ech;kai'HICAL DisnuBrTioN 


oiMill.itioiiB (it level. I am -<troiiirly iiu-line«l to extemi 

th«> above vi«'vr, and to infer that (luriiitr •miii** earlier 
iiiil 'till wiirmer jieri<Mi, xiuh an tlie «tl<U-r I'lioioiie 

i)«Tn)<l, H Iar;re nutiil>er of the Kaine plaiiU and aniiual-! 
iihaliited the almtist contiimoUH tirrutn polar land : 
mil that t)it-e plants and animaN, i.oth in the ( 'Ui 
uid New W orhls, Wtrari -lowly to nufrate -oiilhwari" 

ii-t the (lunate herame less warm, lontr IxMore 


.•ncenient of the iJlatial period. We now see 
'lieve. their desiemianls, tno 

as I 
^tlv in a iiui<liii.(l con 


Ml the eeiitral parts of Kurope and the I niteil 
(In this view we can under-<tand the relation- 
lip, v*ilii very little identitv, between the ](ro<lii.tions 
i<( North Anieric;i and Kurope, a relationship v^nich 
1- nio-t rernarkahle. consideriinr tlo* distance of the two 
iiie.i.-'. and their separation hy the Atlantic ( > Wf 
, ,in fnrther iiiuler-iand the -insular fac-t remarked oi^ 
,\ several oh-»'rvers, that the production- of Ijirope 
lid America durinjr the later tertiary stages were more 
. luseiy related to eacli other than they are at the proent 
time ; for durinir these warmer periods the northern 
[.•i'-»< of the (Md ami New Worlds will have heen aimo.-t 
r>i!itinii..u>lv united hy land, >er\ in-r a- a hridt--*'. -in<-e 
renilere<l impassable by cohl, for the intcrmi;:ration of 
rht'ir iiiliabit.'iTit>. 

I >iir:u;r the slowly decreasiiijr warmth of the I'lioceiie 
[lenod, a-s soon as the spe<ies in comn.on, u liirh in- 
!ial.ite<l tlie New and Old Worlds, mijrrated -outh of 
•li" Tolar Circle, they must have been completely cut 
i(f from each other. This reparation, ;us far a> lio- 
•iiore temjx'rate production- are concerned, took place 
ionj aire- ajro. And as the plant- and animals mi^rraU-d 
-MMthward, thev will have become miii-led in the one 
jTcat re:rion with the native American productions, 
iiui ha\e iiad to compete with tlieni ; and in the other 
-rt'il rt'iiion. with th«)-e of the Old World. C onse- 
.liiciiMy we have here everythiiiir favourable for much 
->, . . _V^*:.._. f,,- r.,.. vY^,.\^4k rY'^fifHhi'.it ion than witli the 

.\l!)iie productions, left i.-<datwl. within a much more 
re. ent {Hiriod, on the several mountain-rmnf^e* and on 

- i 




the ciPlic laiidH ot tl.o two MurldH. lleiue it has 
com.', that when we rompure llu' now liviiitf prctdu. - 
ti(.M< of Uu' Hrm| r.tfions --t tlie NVw \n>\ Old 
W orlil<, we IiikI m'iv If" idt'nlical -i.rcMW (thoii-li .\s;» 
(.rav Jias i"!!..'"!! that nK.n- j.lanb* :iro id.-iitiral 
than wa, forim-rlv ^tl|.po^pd), Lut w<^ tiiid iii every 
Tt-at cla^K many form^, win. li some natunilislH rank 
as iriM) race-, and others as distinct sjx'Cie.s . 
:.n,i a host of .los.-K ..IIkmI or rei-resoutative forms 

hich are ranked hy all naturali-'- 

w hii 

as spoi'itiiMii V 

As on the land. >.. in the uater^ i the wa, a slow 
southern iinjrration of ft marine iain.a. whu-h dunni; 
the I'lio.eue or ev.'ii a somewhat •• irlier period, was 
nearly unitorm alonK tlie c«»ntinuous ^hores ol the 
Polar < ir.le, will ar«()iint, on tlie theory of modihca- 
tion, lor many clos,!v allied f..rms now livinjf in are;i> 
,„,Mpletely sundered. Ihus, 1 we can under- 
sUnd the presence of n.anv existintr and tertiary repre- 
sentative forms on the eastern and western siiores oi 
te-nperate North America ; and the still more ^tnkin- 
caso of many closeiv allied crustaceans (as described in 
Dana's admirable work), of some lish and other marine 
animals, in the Mediterranean and in the seas ot Japan, 
- areas now separated hy a continent and hy neniy a 
hemisphere of ecj'.iatorial ocean. 

Ihfse cases ot relationship, without identity , ol the 
,;, habitants of sesis now di>ioined, and likew-e of the 
oast and present inhabitants of the tomoer.ite laiids ot 
North Aiiien.a and Kun.p'.', are inexplicable on the 
ll.eorv of creation. \\e cannot sa> that they ha\ e 
t,een 'created alike, in correspondence w ith the ueany 
similar plivsical conditions ..f the areas ; tor it we com- 
..are, for instance, certain i>arts of South Aincnca with 
liu- M.utherii coniiiicnts of the Old U ..rl.l, we see 
<ountri.-s closeiv corresponding in all their physical 
, ondilions, but with their inhabiunts utterly dissimilar, 
lint wf must reluiii to our uiorc imiiirtiiate su-ViO^'t, 
the t.lacial i)erio.l. 1 am convinced that Forbes's view 
nun l-e larirelv extended. in we have the 



pUuit'St evid»Mi<»' «it tln> cold |»«'rio<l, troin the wi'slerii 
hhoro- of llrilaia to tlio (Jural nmtre, .iiul M)utliwanl to 
the rvriMuu's. We in.iy infer troin the frozen niainrnal- 
,iiid ii'i'ur*' of lh»' ino iiitiiii ve^.'-ftatiuii, liat SilxTia wan 
siinil.iily atlfited. Aloi;,' fhr Himalaya, at iMiiiits Shki 
mileh apart, »rlat ifr-; havi' liMt thf iii.irksof tht'ir fornuT 
low (l««>.{M»t ; ami in Sikkini, l>r Hooker saw mai/.e 
trrowiiij.' oti ciirritilii- aiicifMil in<)rain»>s. ^outl; of tliH 
♦•(jiiator, \*t« h.i\»' •.•line ill roct evidftire of former trla< ;al 
!u.tion in New /.ealaml ; and the xame plant*", fonntl on 
wi.ii'ly separated mountains iutliat i-laiid, tell tin s;iiii«' 
>torv. If <»!!»> iccMijiit wtiH-h lia> Iwen pultlishrd can It- 
trus'U'd, v»e iiav<' direct e\iilen«e of trhwial action in the 
-()Uih-i-;i»t«'rn rnriicr of A;i«'r:ilia. 

l/ookiiitf to America ; in Wir northern half, ice-tmnic 
• ,„'t)i»'iits of ro«k have Iwen ohserved on the ea^lern 
-,dc a-- houth a> hit. ;i<". -.'57', and on the shores nt 
in- I'acitic, where the climate is now so differeiK, a> south as hit. 4<' ; erratic boulder- hav»', al-o, U«en 
•M.'iced on the Kooky .Mountains. In the ( ordillen of 
i;.|ualurial South .\riHTi<a, jrlacitTs mice eMeniled tar 
h.low their present level. In central ( hi!i I <a- 
l.-'llni^lltHl at trie structure of a nmund of detri;ii-. 
aixiul Wx> fee; in hei^-'lit, crossiii;: a valley t f the .\ndc-. 
md this I now feel convinced was a tMiran'ie morain--, 
lift far lielow any e.xistinir glacier. Further s«iuii> 
■ n l>oth ^idc- of the continent, from lat. -41 to tic 
-outliernmost extremity, we have the dearest evide:i.>> 
.tf former jflacial action, in hujre houlders transported 
: u- from tlieir parent source. 

We do not kiio.s (hat the (ilacial ejMwh w:is strict!) 
-imultaneous at the-e several far distant points on o]" 
pos; ,. sides of the world. Hut we liave tro«Ml e'.idencf 
in almo>l every case, thai the epoch ah- indudcl wi»hin 
•he latest ^Tolojrical peiioii. W e have, also, excelleiii 
evidence, that it endured for an enormous time, a- 
ineasured by years, at e loh point. The cold m.iy have 

» 1.^..r> <<.>'i>.<.1 p-irliiir at olio luiillt (it * }u' 

• tr:::T- tril, •■ft iid - ^-- ^ *. •» ■• •• j ' —- ; - 

:rlot»e than at another, but seeing that it endured tor 
lo/ii: at each, and that it was contemooraneous in ^ 






(jt'olrii.' »i'iim«. if -^-fnis ti> me pr<il».itilf 'liat it w.i.-.,<liir 
iiiC :i I :irt al If Lit of tlit> piTiod, .ittit'ilh •«imiilfniii>im> 
■ lirmii^liniit iIm' Murl'l. \\ itlnHit Minu' <Ii*tiint t»\ it|«>tM«' 
to till' fdntrary, vv«« may at len^t admit ax prnlialdp 
that till" irlanal at-titiii wm* Himnltaiicoii"* on Mm- »T»itfrti 
a'lil wottTii hidtw of North Aiiutkm, in th<'( nnl.liiTa 
iiiiiliT the »'i|iiat«fr and iiiidtT the wariinT t.-m[»»'rat<' 
/"III-,, atid on hoth "iidi's of the >4oiitherii ••\»r'imty 
ot the roiitiiiftit. If this he admitN-d, it i> dilh( iilt 
to avoid helifsi'itj that th»» ti-mp.-rat iir»' of tlo- w[iid«- 
v*orlii WOH at this |H'rio<i 'iiiiiilt.iii«*<Mi-lv cooler. lint 
It would >4nffi(t« tor mv iMiipoue, if t)i- trrnpcrature 
v«a-* ;i' th<' same titn^ h)W»'r ahmi^ rerfam h«dtn 
of hdiiritiide. 

« 'n thi-< view of the whole world, or at U'.i»t of hro id 
loii^ritudinal lultM, haviiijr heeii vimnlLifit misly .-older 
tmiii [ifdf to pole, iniicii lush' « .m hi- thiown on th<' 
I'l'M'tit ili-'trihiitiuii of iiU'iitical and allied '[lecies. 
ill Aineric.i, Dr. Hooker has ^hown that het^i-i-n htrty 
Old titty of the floweriinr plant.s of lierra d»'i Kiieiro, 
t'>rmin^ no inconsideralile part of it.s -tant) fln'-.k, are 
eonimon to Kurone, eiiorinou>'ly remote a-* tlif-f two 
p":nt.sare; and tliere are in.iny rlosfly allied >pe(ieH. 
' 'I the lofty mountani^ of e(jii.itorial America a ho^'l of 
p< ( uliar -pccies l>eh>njriri:r to KurujKvm irenera occur. 
< Ml til.- hiirlu'st mountains of Brazil, some tVw Kuropeaii 
t'> iiera v\(re lounil l»y (iarihier, wiiieh do nut exist in 
liic Wide interveiiintr hot countries. S(» on the Sill.j o*' 
I aracca< the illustrious llumholdt htiij- atfo ton. d 
tijtecii'^ t.«';fin;,' to t'cnera characteristic of the ' o.-dil- 
Icra ( 'n the mount;iins of Ahyssinia, M*\«'ral Kumpca'i 
lui iii>. atiii s(mie few reprt'scntatives of the peculiar tlor i 
ot thi' ( ape of (ioi ' Hope o<'cur. At the ( apt' of < iood 
ill'].,' a \cry tew K i.ipeati speoie.><, helioved not t<» liave 
•ti-u iiitidduced hv man, .unl on the mountain-., ^ome 
few repir~i>ntati\ e Muidpi-an torm> are found, wliii h 
h.i\e nt»t tieen discovered in the intertropical parLs 
o; .iiP. »*."». \ fii me i 1 1 iiiaia^'a, aiiii <>ri ifit} i.-^.'i.'i'c*! 
mountain -rini^^es of the peninsula of India, on the 
iicii:ht.« of ( e\i«>n, anti on the volcanic conci* ,<> .fava 




maiiv plantH orcur. «'ith»'r identically tho wun« (»f r»»- 

[ -<'s«'iititi|f viuh other, and at tlw sanu* timo r«'pr»n'nt.iii(f 

l.itit-H of KiirnjM', not found in the intervpnintr h<»t in*- 

irids. A li»f <)f th»» tfpn««ra colliTtrd on tln» loftier 

iks of Java rainps .i nirtiire of a mlU'rfion tnad« on a 

II in KurojM' ' Still rnor*- -trikitiK "> ''"»* ''ft ''«at 
-.iuth«'rn Australian fornis are I'Uviriy rrpn"^pnt»Mj by 
;.i iitH crowirij'' on the nummiLs of tho niountaini* of 
l;.iriieo Some of thi«j»« Austriliin fonnt. an I hear 
rriitn 1 >r. Hookrr, extend alona: the hfiirlif^ of tht- 
p»'nin«iiia of Malaira, and ar»* thinly sratt«Tt'd, on the 
(•!H' hand ov»'r India ainl on tho other a.«* far north .'w 
J t[>;»ii. 

I'll the Houthern rnountain-; of Australia, Dr. I. 
\I )ll<'r has dinooverpd several Kurr)j>»'aii >iperies ; other 
«p.i le*;. not intro<luced by man, mTur on the lowLindH ; 
and ;i lonsr li'-'t can In.' jjiven, an I am informed liy Dr. 
lioukiT, of K'jro{H>an jfeuera, found in Australia, hut 
tiot in llie intermediate torrid refno'is- In <'•«* ailruir- 
:Uile Introductuin to tti^ hlom of .\'nr Ztainnd, by 
Dr. 5lo(»ker, analojrou«* and s-trikin^j fact** are {riven in 
re:: ird to the plants of that lartre island. Hence we M'e thnnitrhout the world, the plant** jrrowinc on the 
fimre lotty mountains, and on the temperate lowlands 
of the northern and southern hemiMpberen, are some- 
times identically the same ; but they are much oftener 
»[«e( difitinct, thoutfh relate«l to each other iu a 
most remarkable manner. 

Hiis iirief abtrtract applies to plants alone : some 
stricil) aiKiloirous fartM could U- jfiven »)n the distribu- 
tion of terrestrial animals. In marine productiona, 
piniilar cii^es occur ; as an example, I may quote a 
.'em.irk l.v the hitrhest authority, Prof. Dana, tliat * it 
is certain !v a wonderful fact that New /eaia;id should 
liiive a (fo-ier resemblance in it.s Crustacea to <ireat 
U.-ifain, its antifiode, than to any other |Kirt of the 
vorld." Sir J. Iliehardson, also, speaks of the roappear- 
<iine on the siiiirea oi New /.eiiiaud i ii.>>tii.iiii.'», etc., 
mI riorfliern forms of fmh. Ur. Hooker informs me 
tiiat twenty-tive species of .Altr<e are oommou to New 





\i'- i 




! I 

Z»r.ilanfl and t(» Kuropo, but hav.- not been found in tiif 
inicrmediate tropifuf seas. 

It should be olwerved that, tho northern sp.Tuw and 
forms found in the poutliern j)arti5 of the southern hemi- 
-phore, and on tho niountain-raiiire« of the int»'rtro]>iial 
r.'jrions, are not arclir,, hut hehjn^' to the northern tem- 
perate zones. As Mr. H. C. W alson lias recently re- 
inarkefi. ' In reredinjf from polar towards equatorial 
latitud.s, the Alpine or mountain floras really liecon.e 
les- and less antir." Many of the forms livinjf <»n the 
mounUins of the warmer reerioTis of the earth and in 
thf NouUiern lioinisphere are of doubtful vaiu.-, l»»'inif 
r.iiik.'d liy soin.- naturalists as speeirtcally distinet, bj 
others as varieties ; but some are certainly identical, 
iind many, thou^rh i-losely related to northern forms, 
must 1k> ranked iis distinct species. 

Now let us see lijrht can be thrown on tlie iore- 
iroiii;; fact^, on the I>elief, supported as it is by a larjrc 
lK)dy of jreolojrical evidence, that the whole world, or 
a la'rire part of it, was during the tilacial period simul- 
taiK uiijy much colder than at present. The (ilacial 
period, as measured by years, must have lieen very 
lonp ; and when we remember over wliat vast spaces 
M.iiic naturalised plants and animals have eprea<l *ithin 
a few centuries, this period will have been ample for 
.iiiv amount of migration. As the cold came slowly on, 
all the tropical plants and other productions will have- 
n treated from both sides towards the equator, followed 
ill tlic nar by the temperate productions, and these by 
the arctic ; but with the latter we are not now concern»'d. 
I'he tropical plants probably suffered much extinction ; 
how much no one can say ; perhaps formerly the 
tropics supported as many species as we see at the pre- 
sent day crowded together at the (ape of <iood Hone, 
and in i»arts of temperate Australia. As we know that 
many tropical plants and animals can withstand a con- 
siderable amount of cold, many have escaped ex- 
termination durintr a moderate fall of lemperauire. 
more et«pccially by escaping into the lowest, most pro- 
tectee! . and warmest district*. But the -^reat fact to 



bear in mind is, that all tropical productions will have 
suffered to a certain extent On the other hand, tiu- 
temporate productions, after niijrrating' nearer to the 
p<)uat«)r, tlioutrli Iht'v will liave l>eer» placed under nomo 
■*hat new conditions, will have suffered less. And it l^ 
r««rtain that many t<*mperate planus, if prot»»rted from 
tho inroads of competitors, can withstand a much 
warmer climate than their own. Hence, it seems to mo 
[)ossihle, bearing in mind that tl'*' tropical production> 
were in a sufferintj state and could not have presented 
I firm front a^inst intruders, that a certain number 

>f the more vigorous and dominant temperate forms 
nii^lit have penetrat«d the native ranks and have 

t-arhed or even crossed the equator. ITie invasion 
would, of course, have i>een j^reatly favoure<l by lii;r}i 
■and, and perhaps by a dry climate ; for I^r. Falconer 
informs me thKt it is the damp with the heat c»f th»' 
troj)ics which is go destructive to pe. .;ial plants from 
n teiii|)erato climate. On the otliei nand, the most 
liiiinid and hottest districts will have afforded an vlum 
to the tropical natives. The mountain -ran^res north- 
west of the Himalaya, and the lonjf line of the CordiU 
iera. seem to have aiTorded two jrreat lines of invasion : 
and it IS a striking fact, lately communicated to me by 
Dr. Hooker, that all the floweriiiK^ plants, alxuit fort\ - 
six ui number, common to Tierra del P'ue^fo and to 
Kur'ij>e still exist in North America, which must have 
lain on the line of march. But 1 do n«>t doubt that 
some temperate productions entered and crossed even 
tlie .iiu/iind-g of the tropics at the period whei. tiie cold 
was most intense,— when arctic forms had mierated 
some twenty-five decrees of latitude from their native 
lountry and covered the land at the foot of the 
!*yrf'nees. At this period of extreme cold, I believ*' 
that the climate under the equator at the level of tiie 
sea was about the same with that now felt there at 
the iieiifht of six or seven thousand feet. During thi.s 

>L!^^* ,^ 


Upp;!=ii tii 

uir;;r r.,;a! rD uj 

tropical lowlands were clothed with a minjflod tropi 
''al .!id temperate ve^jet-ation, like that now jfrowinjf 

' TK.nBim:- 








with stmiitre luxuriance at the of the Himalaya, a»* 
trrrjphi.'ally <let«TihtMl liy Hooker. 

Ilnis, a8 i iK'licve, a considerable uumh»'r of plant.-, a 
few tt-rrcHtrial aiiimalM, and Home marine productions, 
miirrated diirine the (ilacial pericxl from the northern 
iM'i Honthern temperate /ones into the iiitertrdpical 
r»'<rioii<, and some ev.-n (;ro«j«sl the equator. .\s 
the warmth returned, these teinixTate forms w.mld 
natiiniliy a.M-end tlie hiifher mountains, beintr exter 
riiinat(Ml'on the lowland.s ; those which ha<l not reached 
the e»|ii.itor would re-mij^rate northward or souttiward 
Uiw.irds their former homes ; but the form.><, . liietly 
northern, which had crossed the eijuator, would travel 
-till further fr<»m their homes into the more temperate 
latitudes of the or.|M)site hemisphere. AlthM\i:rh we 
ha\c reason to Indieve from ^eolotfica! evidence that 
ihe wiiole body of antic shells underwent scarcely any 
moditication durintr their lonff southern mitrratioti and 
r»'-miirrati(ui northward, the case may have iM^en wholly 
dilfereiit with those intruding: forms which settled them- 
<ehes on the intertropical mountains, and in the 
southern Iiemi<piiere. Ihese bein^ surround»Ml bv 
stranger- will h.ut! had to compete with .iiany new 
forms of life ; and it is probable that sele«-ted moditica- 
t,.iiis in their .structure, habits, and constitution- will 
b.ixe protitcd tliem. 'Hius many of these wanderers, 
Ihouiih still plainly related by inheritance to their 
hrethren of the northern or southern hemispheres, now 
.xi-t in their new homes as well-marked varieties or ivs 
di-tinct species. 

It is a remarkable fact, strona:ly insisted on by 
Hooker in resrard to .America, and by t aiidoUo 
in reL':ird to .Australia, that many more identical plants 
:iiid lUied ♦orms have ap{»arently mierated from the 
-lorth to the south, than in a reversed direction. \V'e 
see, however, a few southern vegetable lorms on the 
mountains of Borneo and .\byssinia. I suspect that 
thi- preponderant m.^ralion rn>m norlii to suulli ».- 
due to tlie trreater extent of land in the north, and to 
the northern forms having e^i^ed in their own home* 



ill ifreaUT uumhers, and having consequently Ikm-u 
adv:iiif»'(l throu^'h natural wleotion and comjK-'tilKin t<i 
a hiirlicr hUte of perfection or dominating power, t'laii 
the soiitlieru forms^. And thus, when they hemme 
(■oii!iniiit:led durintr the (ilariul {teriod, the northern 
forms were enahled to l>eat the less jK)werful southern 
forms. Just in the same manner as we see at the 
present day, that very many Kuroj)ean produitioii-* 
cover the ^^rouud in Ij I'lata, and in a le.-ser de;rree 
m Australia, and have to a eertaiu extent beaten the 
natives; whereas extremely few iwuthern forms have 
lie<oiiie naturalised in any part of Kurope, though 
hi(!('-. wool, and other ohjects likely to carry si'ed- 
lia\i lieen lartrcly ini|M)rted into Kurope durini: thi- 
List two ur three centuries from 1^ I'lata, and during 
tiie liL-i thirty or forty years from Australia. Some- 
thiiiiT of the same kind must have oeeurred on the 
intertroiMcal mountains: no douht l>efore the (Jhu-ial 

«ri<i(i they were stocked with endemic Alpine fomn ; 

ut these have almost everywhere larfjely yielded to 
the more dominant forms, generated in the lari>»'r 
ireas and more efficient m rkshops of the north. In 
many islands the native prod uctioun are nearly equalled 
or eviii outnumbered by the naturalised; and if tlie 
n;iti\e.s liave not Inseii actually exterminate*!, th»'ir 
iiunil/ers have Wen greatly reduced, and tlii« is tiie 
first hlincc towards extinction. A mountain Ih an 
Island on the land ; and tlie intertropical ruountains 
l»t'fore the (ihuial period must have been completely 
Isolated ; and I Lelieve that the productions of these 
islaurjs on the laud yielded to those produced ^» it Inn 
•he l.irtrer areas of the north, just in the same way a^ 
the jirudut tions of real islands have everj-where lately 
yHt'ltd tu continental forms, naturalised jy man's 
Oijeni y. 

1 aiii f:ir from suppowin^ that all dilficultieu are re- 
inoveu on the view here civen in regard to tlte ntu^-e 
.iiHi aiujiii.'tis 01 the <iiiitxi opeties wiiicn iive «u liir 
iiorthtrii and southern tem|)enite /.onew and on the 
moiiiiUiiu.- of the intertropiral re^fions. \ ery manr 




difficalties rt'iiiaiii to Ix* solved. I do uot jireteud to 
iiidirate the exact line8 and meaiiH of miL^ratiou, or 
the reiison why certain species and uot others have 
mitfraled ; why crrtiiin species have been moditied and 
have ^iven rise to new j^roup'' of form-, and othern 
have remained unaltered. >N'o cannot hope to explain 
■iiich facts, until we can say why one species and not 
another becomes naturalised by man's ag'ency in a 
foreitrn lafid ; why one ranges twice or thrice aa far, 
nT)il is twice or tlirice a.s common, a.s another ^jjecies 
vviiiiin their own homes. 

1 have said that many difficulties remain to l>e solved : 
Mime of the most remarkable are stated with admirable 
ilearne«8 by Dr. Hooker in his botanical works on the 
antijrctic refjions. 'Hiese (^nnot 1)6 here discussed. 1 
v*ill only say that as far as regards the occurrence of 
ideiitical species at points so enormously remote a> 
Ktr^uelen I^nd, New Zealand, and Kue^a, I Wlieve 
that towards the close of the lilacial ptriod, icelier^, 
as sutrjjoated by Lyell, liave been larjjely concerned iu 
their dispersal. But the existence of several quite di»- 
linct specie.s, lieloufrin!; to jjenera exclusively confined 
lo t^a south, at these and other distant points of the 
southern hemisphere, is, oa my the<iry of de.scent with 
modification, a far more remarkable case of difficulty 
K(»r soma of t}i*i!se species are so distinct, that we can- 
not HupjK)se tb;it tliere has been time since the coni- 
inencenient of the (Jlacial period for their migration, 
and for their subsequent modification to the necessary 
iie<rree. 'Hie facts seem to me to indicate that peculiar 
•md very 'iistinct Kpecies have miffrated in radiatin^r 
lines from 8on»e common centre; and 1 am inclined 
to l.tok in the southern, as in the northern hemi- 
sphere, to a former and warmer period, before the 
commencement of the (Jlacial period, when the ant- 
arctic lands, now covered with ice, supported a highly 
!>er!iliar and Isolated flora. I suspect that l>efore thi> 
flora was exterminated by the (Ilacial epoch, a few 
forms were widely dispersed to various points of the 
•aiiithern hemtsphere bv occasional means of transport, 


;iti<i bv the aid, as haltinjf-places, of existine and now 
-unkeii islands. By these means, an I l»elieve, the 
-oiitherii shores of America, Australia, New Zealand, 
hav»< l.orome sli^^htly tintetl by the same peculiar forms 
of veirt'tahle life. 

Sir ( . Lyell in a strikintr pass^me ha.s sp«'<-tilated, in 
l.iiiL'UHire almost identical with mine, on the etfecti* of alternatious of climate on ideographical distri- 
•^iiitio'i I believe that the world ha» recently felt one 
of his (Treat > ycies r' change ; and that on this view. 
rombined with rnodi ition throujrh natural selection, 
. riiiiltitude of facts in the present distribution l>otl. 
. f the same nid of allied forms of life can be ex- 
plained. The living watern may be said to have riowed 
■liirniiT one short j)eriod from the north and from the 
,<»uth. and to have crossed at the equator ; but to 
• .ave tlowed with >rreat*,f force from the north ^o as 
'o ii.iw freely inundated the south. As the tide leaves 
t.s dritl iu horizontal linw, thoujfh risin^r hi^rher on 
'be shores where the tide rises highest, so have the 
tivin ' waters left their living drift on our mountain- 
-unimits, in a line jfently rising,' from the arctic low- 
ianil- to a ;rroat height under the e«|uator. The various 
heinsrs tluis left stranded may l»e compared with savajje 
races of man, driven up and surviving in the mountain- 
. vstri<:v«-es of almost every land, which serve as a record, 
' ill of interest to us, of the former inhabitants of the 
-irromidiut? lowlands. 

1 in-" _i 




I'istribiitl )ii of frt'sh • w:vttr pnvi'ptlimt — <>m the liih»l'lUnU >( 
iMT.itiii; iiilaiiili — AI>^L•lll•l• of IJatraihiaiiH aiiil of U-rr«»tn*l 
MHiiiiiialit On tlic rfliilinii of the iiihaliitatiu >■{ Islaiiils t<> 
tliiise of tlif luaii -t nuiiiliiiiil -On culonisatiiii from the nrarr.-tt 
(...iircf witli HiiiiM'<|ueut iiiiMliflcaUon — Huiuiiiary of tht- liuti anil 
prcsi'iit 1 Iiai>t<r8, 




As lakt's and rivor-systerns are separated from each 
otlipr Ity liarriors of land, it niiyht have Irh'ii tlioiiL'ht 
that fresh -watrr productions would not hav« raM;;ed 
widely witliin the same country, and as the «ca jh 
ajiparently a still more impassable barrier, that they 
n(n»!r would have t'xtendod to distant countries. Hut 
tlie rase is exactly the reverse. Not only have many 
fresh-water species, Injlong'mir to quite ditTereut clashes, 
an fiiormous ran^'e, but allied sjM»cies prevail in a 
remarkable manner throughout tJie world. I well 
rt^member, when tirst collectinjr in the friish waters of 
lira/il. ietdin^ much surprise at the >iiui!arity of the 
fn-li-water iiisectH, shells, etc., and at the di.-v-imilarity 
of thf surroundiiitr terrestrial l>ein^s, compared with 
thoM> of MriUiiii 

Hut tliis power in fres!i-water productions of rai^finiir 
widely, thout'li so uiiexiK'cted, can, 1 think, in most 
cases \h\ explained by tlieir liaviiiif he4'ome filled, in 

-- .-,.,- -^ 1 ,,1 1 -'i- 1 t ii r -_ I _» 1 r__^ 

quent rnu^rations from pond to pond, or from stream 
to stre.iin ; and liability to wide dispers;il would bdlow 


1 I 

GE()C;RArHI(:AL distkibltion .^w 

from this {•Apsu'.iiy as an almoHt iiwe>isary conHe<|u«»!i<*r. 
We ran here cotisider only a few cusv-*. In rejranl to 
fiwh, I l)«lieve that the same hj>et ie» never occur in the 
fre>h waters of distant continent*;. IJut on tlie winie 
(•(tiitinent the ppecie« often nin;?e widely and almost 
c.ipririously ; for two river-systemn will have some fish 
iti coTumon and s«ome different. A few facts s«'»"m to 
:<iv<)iir the ponsihility of their occassional trans})orl hy 
;uTi4lciit;il means; like that of the live fish not rarelv 
dropped hy whirlwinds in India, and the vitality of 
their ova when removed from the water. Hut I am 
iiulined to attrihute the dispersal of frefeh-water fish 
m tinly to slight chautres within the recent jieriod in 
the level of the land, havinK caused rivers to How into 
.ii h other. lustances, alho, could l»e »fiven of thin 
h.ivint; occurred during floods, without any ch.iiiue of 
leM'l. We have evidence in the loess of the Kliiiie of 
runs;derai<ie changes ol level in ihe land ^itiiin a very 
rercut s:«'<>l<>R'*"*l period, and when the surface was 
pLoj.led hy existiujf land and fresh-water shells. 'l'h»* 
•viiie difference of the fish on opp4»site sides of con- 
tinuous mountain-ranges, which from an early period 
,iiu>t have parted river-systems and completely pre- 
vented their inosculation, seems to lead to this -^aiiie 
i'on(lu>ion. ^^'ith respect to allied fresh -water fi>h 
occurring at very distant points of the world, no douht 
there are many case** which cannot at present l»e 
Hvpltined : hut some fresh -water rish helong t« very 
mcieiit forms, and in such ouses there will have U'eu 
ample time for great geographical changes, and conse- 
ijUtMitly time and means for much migration, la the 
set Olid place, salt-water h>h can with care ho slowly 
.iccwstouied to live in fresh water ; and, according to 
\ alenciennes, there is hardly a siuL'le group of tithes 
(ontine<l exclusively to fresh water, h4» that we may 
iiiiau^me that a marine memher of a fresh-water group 
mitrht travel far along the shores of the s»>.i. and ^u^•s•»- 

(Ui iitiy r-c-coine mouiiicd s,:-;] .uiiiptrd Ui the ^resh 

•vaicrs of a distant land, 
.■vime specie-s of fre»*h-water nhells have a very wide 


■ "• SH ■ 


ran^'p, ;iiul niliefl .sjx'cies, which, orj my theory, aro de- 
H<pri(l«(l from a rommoti parpiit aiiri'mti<t havp |iro- 
co.mIimI from a siiitrle source, prevail throturhout the 
world. Their di-f rihution at firHt |>erplexed me niurh. 
n- their ova are nut likely to be transporteil hy l.irdH. 

liid tliev are iniUM-diately killed Ity sea-water, as are 
tlie adiilu*. I could not even understand how some 
•1 itiiralised s[>ecie- have rapidly s|»read throujfhout tlie 
-ame country, liut two fact«,' which I have observed 
and no doubt many otliern remain to be observed — 
flir.iw some li^ht on this subject. When a duck 
>iiii.i<'nly eriierjfes Irom a pond covere«l with duck- 
weed. I have twice seen these little plants adhenny to 
itH l.;i< !< ; and it has happened to me, in rcmoviinf J* 
little «liick-wee(l from one aquarium to another, that I 
have <|uite unintentionally stocked the one with fresh- 
water Bhells from the other. Hut another agency is 
perhaps more effectual : I Buspended a duck's fi'et, 
which mitfht represent those of a bird §leepin^ in a 
natural pond, in an aquarium, where many ova oi 
fresh-water shells were hatchinjf ; and I found that 
numbers of the extremely minut<> and just-hatched 
"hells crawled on the feet, and dunjf to them so firmly 
that when t.tken out of the water they could not be 
larred off. though at a somewhat more advanced a^e 
tliev would voluntarily drop off. Ilie-se just hatche<i 
rnoliusc^, thuuirh aquatic in their nature, survived on 
tim duck s f(.,'t, ill damp air, from tweho to twenty 
hours ; and in this leiiirth of time a duck or heron 
mifrht t\y at least six or seven hundred miles, and 
would he sure to alight on a pool or rivulet, if blown 
HTOS.S sea tr) an o«eanic island or to any other d iiant 

• tint. Sir Charles Lyell aUo informs me that a 
|)\-ticus has been r;iu(,'ht with an .\ncvlus a fresh 
water shell like a limpet) tirmly adherintr to it ; and a 
water-beetle of the same family, a ( olymbetes, once 
»lew on board the Htn'/U- *hen fortv-fve miles 

liistATit frniii rlia iiu:ir<iwt l-iii<4 • I</a<— •»>...!. <.'...<l :^ 

ui'ffht have tidwn wii!i a favouring' jn\,' no on« can 




^\ ith respect to plants, it hait loiipf b<'eii known what 
lurrnouH ran^eit many tresli- water and even niarsli 
pefit's have, both over continents and to the rin<»t 

• mote o< eanic islands. Thiti is strikiriizly shown, ax 
I'Miarkt'd by Alph. de ( andoUe, in larife irroupH of 

■(•rr»'strial plants, which have only a very f«'w atjuatic 

nemhers ; for these latter seem immediately to acquire, 

i-i it' m conse«|u^nce, a very wide ran^e. I think 

'avourahle means of dispersal explain this fa<'1. I have 

'efnre mentioned that earth occasionally, thouifh 

'ireiy. adheres in some quantity to the feet and heaks 

>r birds. Wadinu birds, wliich fre(|uent the muddy 

.(Ijrt's of {M>Dds, if suddenly flushed, would he th» 

Tiost likely to have muddy fret Birds of this order I 

.m show are the (n"<**te8t wanderer*, and are occa- 

MDiially found on the most remote and barren island-* 

. the open ocean ; they would not be likely to alight 

III tiie surface of the sea, so that the dirt would not U- 

• ishvd otf their feet ; when makiiit; land, they would 

'm' sure to fly to their natural fresh-water haunts. I 

111 not believe that botauLsta are aware how charjfed 

he fiiud of ponds is with seedn : 1 have tried several 

lt!e experiments, but will here ifive only the mosJt 

• •.rikiiis fA8« : I took in February three table-spooufu Is 
it'iii'.ii from three different points, beneath water, on 

• ■,,. Hili^M' of a little pond ; this mud when dry wei^hcil 
iiily t)!^ ounces ; I Kept it covered up in my study for 
MX months, pulling up and counting each plant as it 
/rew ; the plants were of many kinds, and were alto- 
M'tiier .">;)7 in number; and yet the viscid mud wa.s 
i'i I'oiitained in a breakfast cup ! Considering the?te 
:.iit>, I think it would he an inexplicable circum.stance 

* water-birds did not transport the seeds of fresh-water 
;iiants to vast distances, and if consequently the rang*- 
"f tht^tif plants was not very great ITie same agency 

ri.iy tuve come itito play with the eggs of some of the 
mailer fre>sh-water animals. 

< -iiifr ami uukiiow:i agencies proiiabiy ijave aim 

• ' ived a part. I have 8tate<l that frp^ ti»h ear 
M)iiie kintis of seeds, though they rejert many other 




kiiKls fiaor having hH;ill.,we«l tlieiii ; vm-u Hmai; Imh 
swalii.u ^,.Hh of n.o«lerat« size, m of the vellow water- 
lily Jiii.l l'(.UmMtr«'toii. IliTonsaii.l other hi^l^, .riiturN 
Hitor .eiiturv, have jfom. on daily .ievouriu<f fi-h; thev 
then take lli>r},t arid jfo to other waters, or are hlowii 
'•.•r(.>s the >ea; and we have Keen that*. retain their 
[.ower nl Kt-niiinatioii. when rejected in pelh-ts ..r in 
excrement, many hour- atlerwanls. When 1 ,s,iw 
^'leat Hi/e at the seeds (,C tlial tine waU-r-lilv, the 
NelumhiMin, ami reinerni.ered .\!i,h. de ( andolles 
remarK- on thii, plant, I thought Lt it* di>trihijtion 
iniiM remain .|uite inexplicahle ; hut v^uduhon Mate^ 
that he found tho Keedn el the creat southern nater- 
ily i.rohahly.a.Twrdintjto Dr. Hooker, tlie Nelumhiun. 
Iiitetim) m a heron'n wlomach ; althoujfli 1 do not kiiov* 
the taet, yet analo^jy makes me U«lievo that a lieron 
tl\mt; to another iK)nd and ^ettin^f a hearty meal >^t 
tisli. won hi i.rolwihly reject from it« stomaih a pellet 
■■onUinuiK the seeds of the Nelumhium undi4fe^ted ; 
'r the heedH mi^ht U- dropped hy tlie hinl whilst 
leedinu' il.s younjr, in the same way a^ hsL are known 
somelimeh to l»e drop|,ed. 

In eonsiderin^ thf>e several me.'ins of distri.,^tion, 
It should !»#» rememhered that when a pond or streani 
IS first formed, tor instance, ou a rising i^let, it will he 
iMUKVupie.1; and a sin^rle Mjad or e«:jr will have a ^'ood 
ehaiice .,1 sueceeilin^r. AithouKh there will alwavs he a 
stniiryle (or life Imtween the individuals of tlie specie-, 
however few, already oceupviu^ any pond, vet as the 
miinl>er of kinds is small, compareil'with those on the 
and, the oomi)etition will proh.ihlv 1^ less severe 
l>etweeii aquatic than hetween terrestrial sj>e<i.-s ; con- 
sequently an intruder from the waters of a foreign 
country, would ijave a hetter chance <.f seizing on a 
place, than in the rase of terrestrial colonists. We 
sliould.aLio, rememher that some, perhaps many, fresh- 
water productions are h.w in the scale of nature, and we have reason Ut lieljeie iliat si-ch !(>.u- h; i;-— - 
chan^n- or become modiiied less .juickly than the h^'h ; 
and this will tive lonj^er time than thi' uverd^^e for the 

(;K(K;HAPmcAL DisnumrnoN 


mitfTatJon of the nam^ aquatic «p«>ri«»n. W'v shotil<l not 
•'(.r^'ot the pruh.ihility of many sp^rips h.ivini^ foriiu'rlv 
'iiiiffvl an continuously as fresh-wnter prjwluctionH ev»«r 
-111 raiure, over immpiis* areas, ami havinjf suhsoijui'nHv 
•♦•(•omo extinct in internie<liate rejfions. But the wide 
i>tril)iitinn ot f re* h - water [ilantx ami of tin* lii»«'i 
iiiimals, whether retiinitiif tlie same identical (■ 'n 
<r ill ^ome fleirree modifieii, I believe mairilv de|»eiids 
• i the wide dispersal of their «eeds and etrirs iiy aiiirnaU, 
imrt* cHpetMally hy fresh-water hirils, which h.ue larifc 
lowiTs of tliiflit, aiui naturally travel f m one to 
..'luthcr and often distant piece of water. \ «*urf, like 
I r.ireful ifardener, thus takes her seeds from a UmI of 
1 piirticiilar nature, and drops them in anoth»>r e<)uall\ 
^♦•ll fitted for them. 

"a ihf Ifihahitnntfi of Orranie lulnn-ix. — We now 

•lime til the la^t of the three cla».«e?* ot facts, which I 

i.ive selected as presentinjf the tfreatest amoiuit «)f 

■i.fticulty, on the view that all the inilividua - Inith of 

•'le vinio and of allied species have descended from u 

iiiL'le jkarent ; and therefore have all proceeded from a 

■ iiiimon birthplace, notwithstandinif that in the course 

' time they have come to inhabit distant {Ktint.s of the 

.'liilie. I have already stated that 1 cannot honextiy 

ulmit Forben's view on continental extensions, whicli, 

:; iejjitimately followed out, would lead to the ixlief 

•I It witliin the recent periml all existing islands liave 

't eii nearly or quite joined to some continent. This 

>'w would remove many difficultien, but it would not, 

tliink, exphain all the factn in retrard to insular pro- 

tiutioris. In the followine remark.s I shall not contine 

ii\Mlf to the mere question of disper-al ; but shall 

. nii.siiier some other factii, which l>e^ar on the truth of 

'K.' twd theories of independent creation and of descent 

* "ti iiiodiJication. 

Hie ■.jiecies of all kinds which inhabit oceanic islandit 
■••c" .1 *•*• 111 4a««iii[K r ; urii litirtii '"^iiii i-iio""** on • tiwrii I'^in- 
lifUMit.Tl areas: Alph. de ("andoUe admits this for planta, 
■i!ii WoUaston for insectH. If we look to the larg^f- 


ON illK OKKilN OK M'K( IF> 




sIm! and varied •*tatiniiH «tf New /ealaiid, <'xt«Mi(liii>f own 
7ttO mill's til latitude, and fompart' itn fl«»weriii:-' plants, 
nnlv T-'" in nuinlicr. with thiixe on an etpial area a? 
tiip (ape of (Jood Hope or in Australia, we rrnist, 1 
think, admit that iMtmethintr <|iiite inde{M'nd<Mitly of 
iMV difference in physical ••()niiitif)nH has raiise<i st» pr'-a* 
I difference in iinniher. Kven tl>e uniform county of 
• .iiiiliridtre ha^ H47 plaiitfl, and the little island ot 
\ii4rle«ea 7'>4, hut a few ferns and a few introduced 
i>lant.s are included in these numhers, and the cuiii- 
pariHun in Home other respect* is not quite fair. We 
iiave evidence tliat the harreti inland of Asi-ension ai»- 
"irig-inally nossessed under half a dozen Howerinir plant*; 
\et many have become naturalixed on it, as they have 
in .Now Ze.-iland and on every other oceanic island 
vhi'h can he named. In St. Helena there in rea.son to 
l>elieve that the naturalised plants and animals have 
nearly or quite extermii:r.*.;'d many native productions 
lie who admits the doctrine of the creation of each 
-eparale species, will have to admit, that a suffit'ient 
iiumher of the best adapted plants and animals have 
not Iwen created on oceanic islands ; for man has un- 
iiiteiiti(»nally stocked them from various gof.rces I'ai 
more fully and |>erfcctly tlian has uature. 

Althoutrh in uceaDic islands the number of kindd 
■ >f inhaliiLants is scanty, the proportion of endemic 
species {i r. those found nowhere else in the world) is 
often extremely lar^e. If we compare, for instance, 
the nuHiher of the endemic land-shells in Madeira, or 
of the endemic birds in the Cialapagos Archipelago, with 
the number found on any continent, and then compare 
the area of the islands with that of the continent, ^e 
>.hall see that this is true. This fact mi^ht have \>eeu 
expected on my theory, for, as already explained, 
species occasionallyarnvin^ after lou^ intervals iti a new 
and isolated di.strict, and havin^f to comi>ete with new 
asso<';ate*, will he eminently liable to modification, and 
•-ill '-({e-ii j-ro-iiicc -jTO"}'- of modified dcsi'ondant?;. Hn% 
it by no means follows, that, because in an island nearly 
all the specieji of one class nre peculiar, those of another 

(iK«H;iiAI'HI< Al. DIS'lKiHl HON 


.ami, -ir of aimlliir sertion ot the winu* «;l;.>-. nrv 

jn'ciiliar ; and tliin diffrrfru •• M>ems to (ir|)«Ti(l itaitlv iti 

'ho i«;><>t-ic.s which «t«» not h«M-om«' nioiiitiiMi having 

rnrniirratrd with f;icility and in a JkmIv, bo that tlicir rrlatioiis have not heeu much 'diMturU.! ; ;inil 

• artly un tlif frt'cjucnt arrival of iiriniodifuMl inunik'r.iiiN 
itm the niotlnT-coiintry, and tJie c«)nKe»|u»-iit iiitor- 

( r<i>»sin^ with thorn. >N'ith r«w|ie< t to the offrrt- ot thi^ 
iiittTfrossint;, it should Im> ri'Mu-niln'rol that the orf-prini: 

• •f surh croHses would almost cert-iinly gAxii in vi^'our ; 
»<• tliat even an oc«asional itoks would prcMluce more 
n'.rt tlian miirlit at lirst have l»een anticipated. I'o jfivc 
I t.'W examples : in the (ialap.iiroH Isl.nida nearly ev«T\ 
l.iiid-hird, hut only two out ot the eleven marine hirds. 
ir»> peculiar ; and it is ohvioiis that marine hirdg could 
irrivf at these i.^iandH more easily than land - l»ird«». 
Uermtida, on the other hand, which lies at alxiut the 
■iiiie distance from North America an the (lalapairo-^ 
l-laiids do from South America, and which h:w a very 
peculiar soil, does not ponsens one endemic land->>ird 
iiid we know from Mr, J, M. Jon«»'K admirahle ac, ount 
-f Bermuda, that very many North American hird-. 
Iiiririj; their jjreat annual mijrrations, vinit either 
[••Tii.dic.illy or occasionally thin inland. .Maiieira d(K>«i 

"t possen." one peculiar bird, and many European aim 

African birds are alirost everv year blown there, as I 

im informed by Mr. K. V. ifarcourt So that these 

two islands of Bermuda and Madeira have been stm-ked 

I'V birds, which for loujf a^es have strujfjjled topetiier 

111 their former homes, and have l)efome mutually 

idapied to each other ; and when settled in their new 

""lie-, each kind will have l>eeu kept by the others to 

I'cir proper place.s and habits, ami wril'l consequently 

: tve been little liable to nuKJificatiou. Any ten<ieiic\ 

t" niodification will, also, have l»een checked by inter- 

croosinu with the unmodified immijjrants from the 

niotiior-country. .Madeira, a^ain, is inhabited by ,t 

;;;.tTiUi .iii,ni)er or peculiar ianii-sheii.t, ♦*iier»i» not 

one species of sea-shell is confined to it* shores : now, 

thoujfli we do not know how sea-«hells are di«|>ers©d, yet 






wp ran see that their p^jtm or larva*, [K'rhaps attached 
In M^awoed or lloaiiiijf timher, or to the feet of wadiiur 
hini*;, mitfht bo transjMirtcd far more easily th^in laud- 
-hoU-i. across throe or four hundred miles of (.jh"!! sea. 
1 he dirierjiit orders of inseotw in Madeira apparently 
[irc<ciit"'is fa<'ts. 

( li'cani*; islands are Homelimes deficient in certain 
clasM'-;, and tS'^ir places are apparently occupied hy 
the otlicr iiili.iliitanl-s ; in the <ialapacos Islands reptiles, 
and in New Zealand ^'•i^'nntic wiriffless birds, take the 
place of mammals. in tlie plants of the (ialapa^os 
l-l;ind»* Dr. Hooker has shown that the pro{K)rtional 
nnml^ors of tlie different orders are very dirferent from 
iviiat they are elsewtiere. Such i-aso are generally 
iccouutcd for by the physical cctnditions of the islands ; 
t)ul tins exphin.ition seems to me not a little doubtful. 
Kacilitv of immiirration, I believe, has been at least aj* 
iriiiKirtant as tlie nature of the conditions. 

Many remarkable little facts could l>e iriveu with 
re-pect to the inliabitants of remote i»l.iniis. For 
in-tance, in i-ertinn islands not tenante<i by mammals, 
some of the endemic plants have beautifully tiooked 
seeds ; vet few relations are more strikniir tlian the 
adaptation of t,'<)ked seeds for transportal by the wool 
•nil fur of ijuadrupeds. lliis case presents nr* difficulty 
0:1 ;nv view, for a liooked seed mijrht l)e trans[)orted to 
Hi island bv some nthe," means; and the plant then 
.>e<"iim:nir slitrhth modilied, but still retainiiiir its hooked 
«ec'i>. vMiiild fiirm an endemic s[)ecie». having- a-« useless 
•iu appendaire as any rudimentary ort^in, tor instance, 
as tlie shrivelled wintrs utiiler the soldered elytra of 
many insular beetles. .Atrain, islaiuls often jxtssess treen 
or bu<hes >ielont''intr to orders whi«h elsewhere include 
onlv herbaceous s(»ecies ; now trees, as Alph. de 
I aiiilolle has sliown, trenerallv hav e, wiiatever tlie cause 
mav be, contined rauire-i- Hence trees would be iittle 
likelv to reaeh distant oceanic islands ; and an herb- 
.• eou- pi ml. liiotiiiij it woiiiO navt- in) criaiiCti of 
»iicces>tullv lompetiiiT in stature with a fully de- 
vt>jnTH'd tresv when esfaMisheu on an inland a.ud havinc 



to compete will. - \aceuus plunls aloiie^ nii^flit rf^dily 
train an advant Uy jrrowiug taller and taller and 

uvortopiiin^ the • tlu-r |)lants. If so, natural »ele<fion 
Hoiild often tend d add to the stature of herbaceous 
plants wlien <rrowiiiir on an ocean-c island, to whatever 
iirder tlu-y ht'loiiifcd, and thus convert them first into 
hu>hes and ultimalfiy into treefi. 

^^ itli n"^pect to the ah>ience of whole orders <iii 
fxeauic inlands, Hory St. Vincent lon^ ago remarked 
that Balrachians (fro^s, toads, newt^) liavo never hecn 
found on any of tlie many i-laii<U with whidi the frrcat 
oceans are sttidiifd. I have taken pains Ly veritv this 
assertion, and I have found it strictly true. I have, 
however, heen a>sured that a fro;; exists on the moun- 
tains of the i^reat inland of .New Zealand ; hut I suspect 
ttiat this exception (if the ini- • 'ation ho correct) may 
'•e explained throuirh ^'lacial agency. Ihis ^MMieral 
ih>eiice of frog^s, toads, and newts on so many oceanic 
-lafiils cannot lie ai-couiitcd for hy their physical con- 
iitioiis ; indeed it seems that islands arc peculiarly well 
titted for these animals ; for fro^s have heen introduced 
into .Madeira, the .Vzores, and Mauritius, and have 
Multiplied <() as to i>ecome a nuisance. But as these 
iiiimals and tlicir spawn are known to he immediately 
' illed hy sea-waU-r, on my view we can see that there 
■vould Ite threat difficulty in their tran.«jK)rt:il across 
'he sea, and therefore why they do not on any 
oceanic island. But why, on the theory of creation, 
ihey slioiild not have l)een credited there, it would he 
very didicult to explain. 

.Mainmals o'!ei aimther and similar I havf 
'•arefnlly searched the oldest voyages, hut have not 
tinivhed my search ; a.s yet I have not found a single 
iiistitriie, free from doubt, of a terrestrial mammal 
(excluuing domesticated animals kept hy the natives) 
iiihahititiL' an island situated aUive ti<H> miles fron> a 
continent or great continental islaud ; and many inlands 
situated at a much le«o distance are e»)ually barren, 
i he lalkland Ishand8, which are inliabited f>\ a wolf- 
like fo\, come nearest to an exception ; hut this trroup 



cannot be considered as oceanic, ii« it lie« on a bank 
connected with the mainland ; moreover, icelterjfs ror- 
iiierly broujjht boulders to its we«tern shores, and they 
may have formerly transported foxes, as so frequently 
now happens in the arctic re>)^ions. Yet it cannot be 
H;iid that small islands will not support small mammals, 
for they occur in many parts of the world on very 
Hmall islands, if close to a continent ; and hardly an 
island can be named on which our smaller <)uadrupeds 
liave not become naturalised and greatly r lultipfied. 
It cannot be s;iid. on the ordinary view of cre-atiou, 
that there has not been time for the creation of mam- 
mals ; many volcanic islands are sufficiently ancient, 
as shown hy the stupendous deyrradation which tliey 
have siitfere^l and by their tertiary strata: there has 
al>;o been time for the producti<)n of endemic species 
heloiitrin^ to other classes ; and on continents it is 
thoujfht that mammals apjwar and disappear at a 
<j nicker rate than other and lower animals, 'iliou^h 
ti'rre>trial mainnui.s do not occur on oceanic islands, 
atrial iiammals do occur on almost every island. New 
Zealand possesses two bat« found nowhere else in tlie 
world : Norfolk island, the Viti Archipelago, the Honin 
i.-laiids, the Caroline and Marianne Archipehi^oes, and 
Mauritius, all po>sess their peculiar l»ats. \V'hy, it 
may be asked, has the supposed cre^itive force prf>- 
(liiced bats and no other mammals on remote islands? 
( »a my view this question can easily lie answered ; for 
no terre-tnal mammal can he trans{M»rted across a wide 
-l>ace of sea, but kats can fly a<-ross. liats have been 
M'eti wanderintr hy day far over the Atlantic < )i ean ; 
aiui two .\orth American specie-* either rcirulariy or 
occasionally visit IJermuda, at the distance of «;(K> miles 
trom the mainland. 1 hear from Mr. iomes, wh»t has 
specially stmiied this family, that many of the same 
sjiecies have enormous ran^^es, and are found on conti- 
nents and on far distant island*. Hence we have onlv 


tie>d through natural selection iii their new hoinee in re- 
lation to their new position, and we cjui understand the 


pr«^«'nce of endemic bat« on islands, witli the altsence 
of all terrestrial mammals. 

i{eside.s the ahsence of terr.'strial mammals in rela- 
Uou to the ri'motencH* of islands from contiiuTits 
ilwro 18 also a n-lation, to a certain ext.-nt 
of distanre, between the depth of the ^ea m-iKtratiinr 
an island from the nei^rhbourinjf mainland, and the 
{.reHence in lK)th of the same mammiferoiis species or 
of allied speci.-« in a more «.r less modified condition 
Mr. U md>or I':arl has made s«mie strikintr ol.servati<.iH 
ou thiH head in reirar.l to the crea' Malav ArchiH«ir.. 
vihich IS traversed near fciche^ by a space of d.^p 
• •< ean : and this «pa«e separate* two widelv distinct 
mammalian faunas. On either side the i.sland^ are 
sitiia'od on moderately deep submarine banks, an.l 
theyaro inhabited by closely allied or identical ,|ij;id- 
r.ijM.iv No doubt some few anomalies o«cur in tliis 
irrcat archipelairo, and there is much difficulty in form- 
intf a judu'ment in some owintf to th.- proUibl.. 
naturalisation of certain mammals throuirh man'- 
;.;:ciiry; J.ut we shall soon have much liirht thrown 
"u tlie natural history of this anbipolaifo by tlic 
admirable zeal and researches of .Mr. Wallace. I ha\e 
liol a.s yet had time to follow up this subject in all 
••;bcr .juarters of the world ; but as far a.s i have iroue 
tic relation generally g,uu\. We see Mnf.un 
sej.arat.d by a shallow .•harinel from Kurop-. and the 
Tii.immals are the same on both sides ; we meet with^ ♦•actf' on many islands .sep;,rated by similar 
ci.inneN from Australia. The \\ est Indian' M;..h|s 
stand ..n a submertred bank, nearly 1<hk» fathoms 
111 depth, and here we hnd American forms, but the 
-Irenes and even the jrenera are distirnt. As the 
am. Mint of modification in all dein-nds to a certain 
<Ui:ri'e im the lapse of time, and a^ durin- rha.-es 
Of Jevp ,t IS cbvmus that islands separated by s}i;,ll«,w 
< banriel.s are more likely to ha.e l,een contioMnuJv 
'"..leji wiuiin a recent {H>nud U>. the mainland than 
islands separated by deejn-r cf- .nuel^. we can under 
-tand the fre.pient relation 1 •.ween the depth of tJi« 



tea and tin ile^^n;- of affiuityot the mnmmalian inhaujt- 
iiit>. of isl.iii'ls w; h tlios« of a neiphl>ouriii)i? '-oiitinerit, 
- ,-iti iiio.\iili<altle r..I;iti()n on the view of mdepen<ieiit 

;,c1ri i)t iT«'ati()ll. 

All the l(in'i.'Oiiiif retnark^ on Cue iuhahitanljH ot 
o.-.'.ini< i<l.tii<l>. ii:im<ly, liie «'carcity of kiuds-tlie 
richness in t';i'i''nHr tonus in partifular claS!4«-< or 
«e«-tion> of clas-*'-. the ahM'n.e of whole irroups. a« ot 
!(atr:u-lii.t)i-. and ot lerrt-Ntrial mammals notwithstand- 
ing: the |M.-.eii.-e .>f a.-rial hats, the sin^'ular projior- 
i.iMii^ of ■rrt.tin nr< of plants, herhaceouH ft>rins 
iiavMi? heeii deveiope<i into trees, ete.,- s(«em to me 
to ae.i-oro hetUT with Uie view of occasional means 
of tr:'!isi»(irl liavini; hecii r.r-ely ellicient iu the lon*j 
course of liruo, tlian with tin' view of all our oceanic 
islands havintr ''•'•'ii furmerl) lOinuKled lt> contniuous 
land with the nearest continent; for ou this latter 
view tlic iiiiirration would prol'ahiy have he»'n more 
I (.iiipiete ; and if inoditication he adinilteii, all the tnrins 
»f life Aiiuld have U>en more ei|t;ally ino.litied, in 
ic<-ord:i!ice with tiie j>aramount imporUnc- of the rela- 
tion of orL'aiii-tn to orii-anisin. 

I do not 'leiiv that there are niaii}' and jrr^^'e diffi- 
culties in understindina: how several of the inhabit-int.> 
of the more rein.ite i>land-. wliether still retaining the 
same specific form or moditied .since their arrival, ''•"Id 
;ia\ e reached their present homes. Uut the prol»abiiity 
of iiianv i>land- havinir existed am haUiiitj-places, of 
which not a wreck now remains, mu-L not l>e over- 
looked 1 will here trive a single instance of one of 
the ca-es of ditK. ulty. .\lmo>t ali oceanic islands, 
even the most i.solated a'.d smalleht, are inhabited by 
hinii >hells, trenorally i-y endenuc species, hut some- 
'ime-< iiy sp,M•ie^ found ei>ewiiere. Dr. Auir. A. tiould 
has ifiveti several intere^liiijr cases in re-ard to the 
land-shells of the i-latids of the I'acilic. Now it is 
noL.'-iotis that land->liells are verv easil> killed by salt , 
I'leir ezir>. at iea."<t "-ti' ii as i na'>c iric';, siiiii :;; 
vsater and are killed hy it. Vet there must he. on 
Miv view, some unknown, i>ut hi;;lily efficient uieani 

(;Kf>r,RAPHirAL nisTRiBrrioN 



for their traii«,>ortHi U'ouhl the just-liatched y«itiiit£ 
urrnsiniially •nvw! uti hud adhere to the tVet of hird- 
roostiutf on tlie ^rnmri!, and thus get transported? It 
.)r('iirrt'«l to nie that land-shells, when hihjTiiatiiiu' and 
*iaving a nifmhranout diajdirayrn o\er tl** mouth o' 
ihe shell, niinht he tlnnted in rhuikc of drifted tiiuher 
\cr(tsx nuM^er.i 'ly wide arms of the sea. And 1 toiiini 
that (several s{>*M-ifH di ' in 'is state withstand un- 
inj ired an immersion ii. sea-nater durinj: lieven days : 
01. »• id these shells was the Helix pomatia. and after 
it. had a^Tiin hibernated I put it in sea-water for twenty 
days, and it [ ^■rfei tly reeovered. As thi-. -pofies ha.n 
a thick caloar uus open !> him. I removed it, and when 
It had formed a new mi nhr;, lous one, I immersed it 
^or toii -en days in sea-water, and it recovered and 
• rawle': .^ay : hue more experiments -ire wanted on 
tills ht.»d. 

The mo.-t stnkintr and import.i'it fart for iis in re-.ird 
to tlie inhabitants of islands, i.s their affinitv to those o! 
liie ...'are-t iiuinlaml, without heinir aetualh the same 
-p»'ties. Numerous instance.- could he (ri\en of this 
fact. I will tnve "hly one, that of the 'ialapajjo- 
Archipelago, situated under the e<iuator, between ;>'" 
..nd r,iM) miles frnip ^he shores of South America. 
M'T.- aimoi<t every product of the land and water Wars 
tl.e 1 niiiistakahle stamn of the Amerir.m eontment. 
I here are twenty-sit land-hirds a'd twentv-rive ot 
these are r;i::ked hy >tr. < Jould a distiint species, 
supposed to have heen created here ; vet the clofie 
rtdinity of most of tiiese b'rds to Aoierican species in 
f'verv character, in their hai)it.s, restures. and toties of 
■ c( , '.vari manifesit. So it is »:th the ottor animals, 
and with nearly all the plants, as shown hv l>r Hon' r 
'H h\-> adii'.iralde memoir on the Flora c? this ar-di;- 
P'dajo. 'I'he naturalist, lookint' at the inhnbitanLs of 
these volcanic islands in the Pacific, disUmt se. eral 
tuiuilrfsl miles from the tontinent, vet leeK that he 
s sUndiniT on Amencai: land. Why should this b*- 
s-.f* wbv should tlie species which are supposed U> 
;..iTt (m'^i) freate<l in the (Jal.ioaeos Ar<hipel.iii((, and 



» ! 



iiowhere else, J.ear so pl.iin a «timp of affinity to th.>H« 
creatoil in Am.'rirfl - Jliere is nothing in the con- 
ditioriH of life, in the ireoloKiral nature of the, 
in thiMr heitrht or climate, or in the proportions in 
which the several clast^eH are awociated toirether, whirh 
rPM'nii.l.'H closely the roiulitions of the South Am.rican 
coast : in fact there is a consiilcrahle dissimilarity in 
■ill th.->-e rcspecu. ( >n the other hand, there is a con- 
sidcrahle decree of ^esemh^.!H•e in the volcanic nature 
of the soil, in climate, height, and si?^ of the islands, 
l)etw(>entlie(;al,Ti.,'i:rosaii(| ( apede \erde ArchijK'ht^ros : 
hut what an entire and a'«soiuto difference in their 
inlial-itvirits : 11,.' inhahitants of the ( ajw df Verio 
lsl,li|(J^ are rolate.l ^o those of Africa, like tho^e of t'le 
(iai.ipacos to Amerira. I helieve this errand fact can 
receive no sort of exjilaiiation on th.> ordinary view nf 
in(i."p..rident creation ; whereas- on the view here main 
Uiiicd, it is obvious that the (laiapa^os Mands won!.' 
he likely to receive colonists, wliether hy occahional 
means ol transport or hy formerly continuous land 
from America; and the Cape de Verde Islands from 
Atrica; and that Puch colonists would he lia'de to 
modification ;-the principle of inheritance still lietray- 
inj; their firiffinal hirthplace. 

Many analo;rou8 facts could l»e eiven : indeed it is an 
almost universal rule that the endemic productions of 
islands are related to those of the nearest continent, or 
of other near islands. 'ITie exceptions are few, and 
nio>t of them can be explained. 'Hius the plants of 
Kcrffuelcii Und, thoii;:h standing: nearer to Afriia than 
to America, are related, and that very closelv, as we 
know from Dr. Hooker's account, to those of America • 
hul on the view that this island has heen mainly stocked 
hy seeds broug-ht with earth and stones on "iceher-s, 
driited !.y the prevailiner currents, this anomaly dV 
Tpix'ars. New /eiland in its endemic plants is much 
more closely related to Australia, the nearest mainland, 
than to any other reirion : and t!ii» i- wliat mi-'ht b-.v^ 
(►een>ected ; hut it i« also plainly related to South 
Am.-nca, winch, althoueh tiie next nearest continent, 




\n no enormously remote, tliat the fact beromt^ an 
.inomaly. Hut thif difficulty almcmt disappears on the 
view that l>oth New Zealand, South America, and 
other southern lands were Ions: a^o partially (itocke<l 
tVom a nearly intermediate though distant point, namely 
from the antarctic islands, when they wore clotlie<l witli 
vegetation. In-fore the commencement of the <Jlari,il 
perio<l. ITie affinity, which, thoutrli feehlp. 1 am 
asHurod l>y I>r. Hooker is, between the flora of the 
>*out!i-western corner of Australia and of the (ape of 
(Ji>o(l Hofic, is a far more remarkaliie ca»e, and is at 
j)re'<ent ine.tplical)le : hut thi« affinity is confined to 
the plants, and will, I do not doubt, be Konie dav ex 

11k^ law which cau-es the inhabitant* of an archi- 
peliifi'o, tli()ut:h specifnally distinct, to be closely allied 
to tlio^e of the nearest continent, we ^ometinles nee 
displayed on a itmali scale, yet in a most iiitere.«<tin:i 
manner, witliin the limits of the same archi[)el;u:o. 
Ilius the several islands of the (J;'.laj)a:ros Ar» hipelaifo 
are tenanted, a^i I have elsewhere shown, in a quite 
marvellous manner, by very closely related species ; 
so that the inhabitants of each separate island, tlioiicli 
lno^tly di«itin(-t, are related in an incomparably rlos«'r 
de^Tee to each other than to the inhabiUiiits of any 
other i)art of the world. And this is just what mij:ht 
ha\e Iteen exj»ected on my view, for the i lands are 
situated so near each otiier that they would almost 
certainly receive immigrants from the same oritrinal 
souri »*, or from each other. But this disj»imilarity 
l)etwt'i'n the endemic inhabitant>i of the island* mav 
be Used an an arjfument au'ainst my views ; for it may 
be asked, how has it happened in the several island- 
situated within sij^lit of e-'u']» otliT, havin;; the same 
y.TiIofiiciii nature, tlie sume height, diitiat*-. etc., that 
many of the immigrants should liave been ditferentK 
ino<l.:ied, thoutrh only in a sm.ill decree. Thi* lonjf 
.aiiiM'.ired to nie li irreit difFlcuitv : but it -irises in 
"iiief part from the di'e[>ly- seated error of con-ider- 
inp tlie physical condition."* of a lounlrv a.s the m t 





important for iN; w}„.ro,-,s if ,a„„ot, I think 
.e d.sputnl that the nature of the other inh^h.^nt*! 
« h which e,u-h h,.H to compet.., i. at ioant a., imnort- 

M„ce.s. No.v ,f ^.e look to those ,nha!.itant.s of the 

of tZ'T •,V'';,"''V'^'-" "•'''■'' •''^•' f'"""J i" other inrt. 
em. i ^'''y;'^' •>" '>»e .ide for the moment th. 

endemic .pecTs, wh.rh cannot he here t.iirlv included, 
Hs veare con.Hleru.;. how they have come to he modi- 
lu'.i . n.e the.r arrival), we find a n.nsi.ierahle amount 

mi.;! in";"". '." *'", '"'"'"' '■'^'•'*'"'^- ''■'"« -litference 
"Ufh indee,! have been expected on the vie^ of the 

Inland, having, heeri stocked by .u-ca>ional means of 

^r.ins,,ort-a seed, for instance, of one plant iiavi,,^ 

-nhro.n:ht to one island, and that of another plant 

'" another .>land. Hen.e when n, former times an 

nnm:,,-a,it settled „n any one or more of the <.r 

when 1 Mihse.,uentlv spread from one i.sland to another, 

wo„ld ,„„,nuhtedly be exposed to ditferent condi- 

to compete with different sets of or^ariisms : a plant 

or m. a„ce. uouM rind the hest-fitfed ..round Inore 
rfc. ly occupied hv distinct plant, in one islaiM than 

nano her and it would he exposed t<. the attacks ot 
somewhat different enemies. If then it varied, natura 
^elec ion x.ouM prohahly favour dirierent va. .,tie« i, 

he dirierent inlands. Some species, however, n?!^h 
^ .rca.l and yet retain the same character throughout 
'he .^roup, just as we see on continents somo specie^ 
^pwidin- widely i^tul remaininjr the same. 

he really surprising ta,t in this case of the (Jala- 
I'.i^'os Archipela-o, and in a le:,ser decree in «ome instances, is that the new snecies formed m 
•. n.i separate islands have not (piickfy to the 
-.Hier islands. I{.t the, thotieh' in si.^ht of 
each other, are sepamted hv .leep arms of the sea in 
n.o<t case.s wider than the Hriti.h Channel, and there 
• H no re.Lson to suoDose th.-it th'"' ><-•.- -» •..- f— -. 
F.ono.1 l.een continuously united." Hie curren'ts'o/the 
8ea are rapid and sweep acres.- the archipeL-o, and 


falpfj ..r wiii.l are i-xtriorflinarily' ; no th;it the 
iBl.nml- are far more etfectually separatod fnmi earh 
otli.T tharj lliey appwir tn \>v on' a map. N' 
air.xHl many «pories, ()olli tlxwe found :u nthvr parti* 
i»t the world and those confinod to the archi[.«'{aifo, 
in- common to the >*pveral i«laiidi-, nnd we may inter 
irom (.Tt.iin fact.- flii-.-e have pro^Kihly spnvi'd from 
"Mvip ..lie i..l:ind to tlin othor^. Mut we'oftcn take, I 
Miink, an err.m.'otis view of the probahility of .Josel'y- 
•lili. li spf-ci*-!* invadinir each other's territory, wlifn put 
into frer intercommunication. f'ndouhtedlv if one 
-prcie.i iias any advantatfj, whatever over another, it 
will in a \.vy brief time wholly or in part'it : 
lut if hoili are e<|uallv well fi'tt.'d for their own pl.ue- 
.n nature, hofl, prohahly will hold their own places and 
kr»'|. ^tparate for almost any lentrtH of time. Meinc 
im;Ilar with the fact that many sneoies, naturalised 
'tin.i'urh man's .Mrenry, have spread with astonishing 
r. j.ty over new countries, we are apt to infer that 
!i: .-t aperies would thus spread; hut we should r»- 
rn» mta'r that the forms which become naturalised in 
new countries are not eenerally closely allie<i to the 
a''> inhahitants, hut are very distinct species, 
'•■loi'L'-in^ in a lartje propt.rtion of, as shown hy 
Mph do (andolle, to distinct ifenera. In the Cab 
• vi.'os .Ar.hipelatfo, many even of the birds, thoutrh m. 
'.11 ad.apted for flying from island to island arr 
iistmct ou each ; thus there are three closelv-all e.l 
-pe<ies of mockin^-thrush, each conHned to 'its own 
"-land. Now let us suppose the mo.-kinp- thrush of 
t hatham Island to be blown to ( harles Island, which 
n:L< It., own mockin^'-thrush : why should it Buccecl 
.n est;,Mi>hin^ itself there .- We may safely infer that 
( har.e.s Island i.s well stocked with its own specie.-?, for 
■iriniiallv more e:rirs are laid there than can fxKssibly J^ 
^' Mred ; and we may infer that the mockitijf- thrush 
('«'-'iliar to Charles Island i.s at a.s well fitted for 
' hou.r, i, i^ the sp.-cies peculiar to ( haUiam Island. 
■r ( . Kyell and .Mr. Woila.ston have communicated 
'o ifif « ren.arkaMe fact '.earinsr on this aubjcct : 




namely, that Madeira and the adjoinini^ islet of Port/t 
Santo poHHeBfl many diMtinct but ropr>»«entative latid- 
nhrils. Ronie of which live in crevicPH of «tniie ; and 
;ilth<nij/)i larifp quantitio* of Rtone are annually traiiH- 
portisl trorn I'orto Santo to Madeira, yet thiw latter 
island lias not Iwromo coloniswl l»y the I'orto Santo 
8|»ei"ies : iH'vi'rthelpss hoth ifiland- have Inen rolo!ux«'d 
by 8oni»' Kur()p<Mn land-HhelU, wliiih no <loul)t hail 
some ;nlvaiit«fre over the indi«{eiious --peries. Krom 
tiipie coiisideratioriB I think we noid not ereatlv 
marvel at the endemic and repres«'iitativo Kpecit>, 
wliich iiihaliit tlie neveral i-ilainis of the (i Lipruro-^ 
Archipelatfo, not liavinjf iinivcrwiliy Hjiroad from 
i.-lan<l !i> i»iland. In many other iii'-tancen, an* in tlie 
sevrral districtH of the name continent, pre-occiipatixn 
hi-i probably played an important i»art in chockinjf the 
comniinglinjf of sp»'iies under the same conditions of 
life. Hiiis, the Kouth-east and Houth-west corner* of 
An>;tr;ilia have nearly the same phywical conditions, 
and are united by continuous land, y»^t they rire in- 
habited by a vast numlier of distinct mammals, birds, 
and plaiit>. 

I'.ie principle nhich determines the jreneral rb ir- 
acter of the fauna and flora of oceanic islands, namely, 
that the inhabitants, when not identically the same, 
yet are plainly related to the inhabitantB of that rt-irion 
whence colonist* could nio«t readily have been «lerive<i, 
- the colonists having been subseijuently modified and 
better fitted to their new homes,-- is of the wide«-t 
applicatirin throughout nature. N\'e see this on every 
mountiin, in every lake and marsh. For Alpine 
species, excepting? in so far as the same forms, chiefly 
of plants, have spread widely throuirhout the world 
durint; the recent (ilacial e|M)ch, are related to thn>ie of 
the Kurroundiuff lowlands ;— thus we have in South 
America, Alpine liumminaf-birds, .\l[iine rodents, 
Alj)ine plants, etc., all of strictly American forms, 
and it 1;^ >>bvio"= *}i"* s rr*o!!?;t;;i!!, a- it be^'-r"*^ t;|ow!r 
uphe.ived, would naturally be colonised from the 
•uiroundin:{ lowlands. So it is with the inhabitant.- of 



oeo(;rai»hical distrihc tion 


lake* and marthoa, excepting in ao hr tu* ertmt facility 
of traiis{K)rt haa trivftn the name jceneral fornn to th* 
v»hole world. We B«»e this aamo priucij.!*' in the Mind 
;iriimaN inhahjtinff thp raves of America and of KurojH?. 
Other analosrouH fact* could be jf'ven. And it will, I 
Iteiieve, \>e universally found to !.<• true, that wherever 
in two reifions, let them l)e ever «o distant, many 
rloiely-aliied or representative iipeciea f»ccur. there w.fl 
likewise be found some identical siM'cien, Hhowiin;, in 
accordance with the forejfoin^ riew, tliat at some 
former j>erio<l there has ».een intercommunication or 
mi^rratir.n hetween the two re^rions. And wl.ereMT 
many closely-allied species occur, there will l»e found 
many forms which some naturalist* rank as distinct 
-I'ecies, and some a« varieties ; these doul>tful fort i* 
Hlinwinp us the steps in the process of modification. 

B pi 


Ihi-< relation bietween the power and extent of 
migration of a species, either at the present time or at 
some former {)eriod under different physical conditions, 
and iho exi.stence at remote point* of the worici of 
"tlier species allied to it, is showii in another and more 
reneraJ way Mr. (lould remarked to me long .itf... 
*hat iu those irenera of birds which r^uga over the 
world, many of the species have very wide ranges. I 
can hardly doubt that this rule is jrenerally true, 
thoMtrh it would be difficult to prove it Amon^nit 
mr»mmal«, we see it strikinjrly displayed in Bats, and 
it! a les.ser depree in the Felid* and (anid*. We .see 
it, if we compare the distribution of butterflies and 
fK-etles. So it is with most fresh-water productions, in 
which NO many genera ranj^e over the world, and many 
Individ uiil specie* have enormous ran^s. It is not 
mea;it that in world -ran^injf jfeuera all tlie species 
have a wide ranjre, or even that they have on an 
a\-4-r,i,jf a wide raiiije ; but only that some of the spe< iw 
raiitfe very widely ; for the facility with which widel- 
ranirin;,' species vary and pive ri.-^e to new forms ni!l 
iart;eiv delejuiine iheir average rantre. For iustan e, 
two varieties of the same upecies inhabit America ar-i 
Kuroijc, and tiie species thus has an immen'* ran^e ; 











1^ ||2.8 






1 2.0 






-.-^ ,^., Phon« 
■ 6) 288 - 5989 - Fq. 





but, if the variation had been a little Kreator, the two 
varieties would have \teen ranked »s distinrt sppcjes, 
aiid the .' mrnoii ranee would have l)e»Mi u'rcatlv 
reduced, .-^till les-* i> it meant, that a sr>e«'ips'"-.vhioli 
fipparently h,i« the .apncity of crossin? harrier* ind 
rantrinif widely, a« in tlie case of certain powertnlly- 
wiii^M'd birds, will necessarily range widely ; f.,r we 
should never fort'et that to rariire widely implies not 
only thf puvM'r of crossing harriers, hut the m^re im- 
portint power of hein^ victorious in -iistant lands in 
the strutrjfle for life with foreiifn .•\>sociates. Hut 
on tl.M view of all the species of a ^enus havinsf de- 
scended from a sinijle parent, thou^jh now distributed 
fo the most remote points of the world, we ou!?ht to 
nnd, 9nd I believe as a general rule we do find, that 
some at least of the species range very widely ; for it 
H necessary that the unmodified parent should ranj^e 
widely, underiToinpr modification durinj? its difTusioii, 
and should place itself under diverse conditions favour- 
able for the conversion of its offspring, firstly into new 
^.iriefie8 and ultimately into new species 

In considerinji: the wide distribution ot certain 
c«Mipra, we should hear in mind that some are ex- 
tremely ancient, and must have branched off from a 
' ommon parent at a remote epoch ; so that hi such 
ase? there will have been ample time for great cli- 
mata! and geographical clianges and for accidents of 
tranfii-ort ; and consequentlv for the migration of some 
ot the species into all ([uarters of the world, where 
they may have Income slightly modified in relation to 
th»^ir new conditions. There is, also, some reason to 
behove from geological evidence that organisms low in 
the scale within each trreat class, generally chatiire at a 
s ower rate than the higher forms ; and consequently 
t!ie lower forms will have had a better chance of ran^-inif 
■*uloly and of still retaining the same specific character 
I his lact, together with the seeds and eggs of many low 

»raioj>ortati.)ri, prof ably accounts for a law which has 
h'ng been oh<erve<l, and which lat.-'y \»^a »dmirablv 


d.*t.u6.*ed by Alph. dp (andolle in re^rd to planU, 
namely, that the Iow»t any »rroup of orjfanismn in th.- 
more widely it ia apt to ran^o. 

I he relations junt di^-ussed, - namely, 1o-a au.i 
sowlv-chau^nir ortanisms rariKiuif more widely than 
the h,^h,^«ome of theHjH>ciesofwidely-ranifinK jrenen 
themselves raiiKnuK widely, — such facta, as alniii.. 
lanistnue, and marsh productions beinjf r.'lated (with 
t)»e exceptions Wfore specified) to those ou the sur- 
rotindiiiir low lands aud dry lauds, thouph tlie«e st^itiofis 
are so dirfcrent,- the very close relation of the distinct 
bi^'cies which uihabit the islets of the same arch ipelairo 
and especially the striking? relation of the inhabitiints 
ot each whole archiiielairo or islaiid to those of the 
iiMrest mainland, - are, 1 think, utterly inexplicable 
on t!i« ordinary view of the independent creation of 
each gpeciea, but are explicable on the view of colon- 
isation from the nearest or readiest source, together 
«i;h the subsequent modification and better adapUUuii 
o« tiio colonists to their new homes. 

Sutnmnry of Uist and prtsrnt Vh<ij,ter». —In these 
ciMpters I have endeavoured to show, that if we make 
'iue allowance fi.r our i^orauce of the full e!Tect« ut 
all the chantres of climate and of the level of the land 
which have certainly occurred within the recent period' 
and of other similar chau^CH wliich may have occurred' 
within the same period ; if we rememWr how pro- 
fouiuhy ijfnorant we are with resjiect to the manv 
and curious means of occasional transport,— a subjeci 
whuh has liardly ever been pro|>erlv experimentised on ; 
It we l^ear in mind how oflen a species may have ranged 
continuously over a wide area, and then have Inn-ome 
extinct m the intermediate tracU, 1 think *fe difH 
culties in lielieviuff tliat all the individuals of the name 
species, whenner IcK-ated, liave descended from tlie 
name parents, are not insuperable. And we are led to 
t.-iis concliiiiou, wh'cii ha.s been arrived at bv many 
naturalists under the denipiation of single i-eiitre* of 
creation, by uome ffeueral coiwideraLious, more eupeciall v 

. --r-4i^?,ui!. 


from the importance of barrierH and from the aualo«nc«l 
.iMtnbution of 8ub-^,.nera, genera, and fam ,!...«. 

V\ ith resoect to the distinct species of the name 

-enuH which on my theory must have spread from one 

pirent-Kource; if we make the same allonauces as l^fore 

c.r our lirnorance and remember that some forms of 

i»e . nan^e most slowly, enormous periods of time iH-ioir 

hu^rHnted for the.r migration, f do not think that 

the difficulties are insuperable ; though they often are 

in this case, and in that of the individuals of the same 

species, extreme) V jfreat. 

As eicemplifyin'^ the etfects of climatal rh-w.^e^ ou 
distribution, i have attempted to show how important 
hiis been the influence of the modern (ilacial period, 
^ iirh I am fully convinced simultaneously atlV.ted the 
whole world, or at least ^reat meridional beit^ As 
showing^ how diversified are the means of occasional 
transport I have discusse«l at some little length the 
means of,er8al of fresh-water productions. 

if the dijhculties be not insuperable in admitting 
that in the lonjf course of time the individuals of tliV. 
s.'ime sj^eciea, and likewise of allied spt^cies, have pn^; 
.eeded from some one source; then 1 think all the 
errand eading fa.:ts of ^ei,»traphical distribution are 
explicable ou the theory of mi^rraUon Ofenerally of the 
m<.re dominant forms of life), together with subseuueut 
modihcation and the multiplication of new forms WV 
can thus understand the hitfh importance of barrier^ 
whether of land or water, which separate our several" 
zoo ojfical and botanical provinces. \V« can thus 
understand the Imalisation of sub-fTonera, genera, and 
families ; and how it is that under different latitudes 
for insuiue in South America, U;e inh-Mtants of the 
plains and mountains, of the forests, marshes, and d.»serts 
are in so mysterious amanner linked together bv.uffi'nitv' 
and are likewise linked tx> the extinct Umiu^s which 
ormerly inhabited the same . ontinent. Hearing' in .lind 
that the mutual relation of onrunism to or-anism is of 
1!=--- :::i;:ic-..L i;i:p<;rUriCC, we lain see why two areas havinir 
nearly the same physical conditions should oflen he 


nut o horn to enter, either in neater <,r le^.V^rC 
.•„fir ornot, a.s those whi.h enteral hi. . . ' 

-; ■■ -ly related ,„ eaC, other, .ndllw « W V "tei 

.'ii;. :,;;:"::',,::.,;'";: 'f '■■•, — * <■-".":!; 

rived. «->?..r..!!'.^.. ""f ^ "■"' I'"'''"''''' *•■ 
tJ.e p,e«oc, „f Idemicl .pece,, J''^^:! u, 




do^tful .pedes. a,H of distinct l.ut repraser.Ut. 

A. tl... l;.t.. i:,lvvard Forh.s ..ft.M. in.i.tocj, there i, 

r. L ' ■ '' ■'"■' '^'•'V'-'""-' '»'« "un-cssion of lorn 
pa.t nu.s |.e,n.. n.arly the .s.unc uith tho.e «.u " 
m^ at the pre>ent tune the differences in \uZll 
ana.. W o ^ee this ui inanv fact^. rj,,, endu, .n.-e 
-h npenes and ^n.up ol^.eeies is eontinuou^ ; ^i 
tor the ex.e,. .ous to tiie rule are ho few, that tl ev Z 
fairly }>e att.;h.,ted to our not h.-.vinir « s v "t H ^ 
m an in,e..u..l.ate deposit the f^!!: :^.^ ^^^^ 
absent, but o.-eur ahove and helow : m, „ .a'" 

♦^.roups 01 spe<,e.. belonjfintr either to a cer -^ ' i 

•>f time, or to a certain area .re oC oh .r-L; -'"T'l"' 

iii.l lliat Miuri. (,r«aiiism» differ lllll,. »l,il ' , 

tr-atl . I,. I„,i|, t„„p ,„j space the l.,wcr mem Wr7^( 
a.), ,1.1,,. ,.,.„,ra|lv ,-l.a„;;e L» than tli,- iS „ t ,?, 


quart..r«. ,„ l,.„"l'-'i/j'.';:,, ;"_'"-' "".-"""l "'to di,la„t 



= if V ;>&;=: 

S3i£4rjS?' .it;?)^,^^!^ 




r.K( HiHAPUH AL Dis nun[ rio\ 

atiori ; «ri(i tlie more iiparlv anv »«.. f 

- f-!"'"l, the nearer tl,; 'in'^, ^^ ,^'"'7 «7 -''''^^'^ 

"tfH>r iri time and .j«ce in hoth . i« f T"^ ^c '"'''^ 



' MAI'TKFl Mil 


-'• rr.w Afn.viTiKs ,n- ohnam. hf.isoh: moih-holoo 

KMIlUVofooY : Kl LIMKNTAltV OI».;avs 

.).-.■• nt with n,..,|inr«tlr,n-ClaMm,M|.,', o/ varlM^. o7, 

-A-;,, ti. «. een.-n,l. ,o„,pi„ „„, rH.n.ifinK- Kxti „ i .n il^;!^ 
an.l .!. •l„..-i:r..,:,« M,,r,.h,.i..,.v. i^.,«..en mi..n^^ri f O.o ,a 

in'.M th.. fir.t .l.iWM of life, all orjranic hoinen nro roun 

•n r.'MvnM,. oa.h other in <l,s<-.„.ii,u; dtvre,-., .o thf 

t H.V ran 1... rla^vf,! iri ffroupn under irrouiw 'n,, 

;-..-.^MfMati..n h evidently not arhitrarv like the ^rour 

■ n- of the star^ in constellations. ■H.e existem-i. t 

trn.iij.^ would have heon of simple sie-nifieati.ui if on 

-roui) had heen evclusivelv fitted fn inhahit the land 

and anot.ier tlie watrr ; one to feed on flesh, anothe 

-n ve-..tal.le matter, and so on ; hut the case is wideh 

•iiff.'rent in nature : for it is notorious how commoni; 

'"••'Mhors of even the same suh-^rroup have differen 

hah.t-s. In our second and fourth chapters, o„ \-ariatior 

and on Natural .^election, I have attempted to show thai 

1 IS the widely ran^ri„.. ^.e mu-h diffused and conur.on, 

that IS the dominant species helon-intr to the larirei 

crr.era. whi.l, vary mo.f. "n.e varieties, or incipient 

^fvPCiCH, thus produced ultimately iK^come converted a« 

I ••elieve, ,„to nev. and distinct sptvics ; ami the^.'on 

'..f priu. ipie oi mueriunce. tend to produce other new 






.r. MOW I„5P, i„, which JerAXLl .''"''''•' •''"•'^ 

"f natur*.. there is s cln.t^ra terTI *: <'<'o, 

i.oki„eatt^eI.r..t 1 ^r^^r^^^^^^^ ""Pr-^-' by 

•n a,u .mall are;, cor, ^ 1 /h f"'"'"'' '*' 'i^'* -'"^h. 

' also to -lu^/thTt t- ' ' 
•I'"] ,l;veririnir in .harnrfer f '"Toasu,^ ,„ ,„„„f.^r 

'<>" I-. duer^ent ti-. I . "''^^'•■'"!"'''^ '"xternnnate 

-"- ' -'i-i the'VJ;;;;';:!-;;;; • -| f'T""'"'^ 

''"'-tratinjftheartion as formp^lJ . ^^\^ <f'-';rrarn 
"«" pr..eenitor hecome hroU, ! P'-ocee.lirijf from 

'"•".•.Line in';r„^i*"'''i " Tir";;"-- '""• '"'■"'""' 

' from a i-(unmori nar...,f „» ^i . ...-. '• *""cn 

'^■"-iiKin riarifj. \»h rh 

•;mm..„ parer.t at the riftf, .ta..e o 

;'— t. Th,., fi.r;; ';^T . ■; ''" '^'^!' •^^^••'« "' 

'•-. i" common : aruJ they fo n a ' ''•,""r"^-' '*'""^''' 

^''^•;t liari.l. nhi.h .livfr^-H "^^ '"*'" ^" ^^•■" 

,,, 1 . K» "era, liexeriilod from ( \.\ c 

^T-u-r liNtirirt from the .r^M<.r J "^'^ni f\), furnian 

rtii<i ijito one cla.«s. 'T\\\i% 



'HK OHKWN (;K .vf'KLJF> 

'*'-^'r;w..i u,i u. natural l.i.tor; ni ti... .„|,or.lin. 

-e,..rat,n.Ml.o.o«hi..h an- mo.t unlike ; o a .':«" 

tl.n-|. cornm.m to the do^r-^enu.. and Ui^/ I v aH " 
-.d. sente„o.. a full des.r.,.tio„ is ^rve^ o " o^r k 

luoputal.le liut many naturalists think tliit «n^ 
nn.^ more ,s ^e..nt by the Natural s's^^ • "^ 
'" "^t'/luf It reveals the plan of the ('Vea^r • 
«"1"- .t ... <,K..nfied H-hether order , .^inTor ' J 
or Hhat else is meant hv th- plan of t .« ? I^ 
reern. to n,e that nothir,, rLj ^de l"'to"o 
knowledge. .Surh exnre.-<sions an that hT a,.d which /e otlen mtet'';! h'^ir. mc.';: 

'o;;u' ri::;' ufatT' ^''^^ ''" ^''^^•"•^«"' ^^^ - "-" " i 

in iiii 

icient timen thnuk'ht) thaf tf 

.LTu.turn^lMch (lefrn.inecl the hal.iu of" I 
.♦•fuTal of tacfi l.p 

i«»tM' jKirtjj of the 

iiitr in the .-com.riiv of mit 

• nu ,1 W of very hi^h i..,,.,.rUm-e in .1 

i»»*. and fh»' 


Nnffjititr cAii h(« 

ninre false. \( 



•flrnilanty of a mouw to » nhrew, „f « j 

f>riere:rr,rris the externa; 

"f .» ^hale to a tish 



tu of 


ariv im 

f-*^. tfioijt.'h Ko intimate! 


ii-'Tjif to a vOiale 



iff*' rt'sefii 

'•' <>t the heiriL'. arf ranked 
kiI"_'1imJ fJiaraftiT-*" ; hut to t\ 

y connert,.,! *ith the m hoi. 

Alfc'lH. '] 

^ merely ' adapt i^w 



• " • ■■"!. lo iiiB rolls 

re..,Mhbnr« ue ^h;.ll have to reeur. ft may even U- 
if.v.M as a .^eneral rule, that the less a iv^rt oV uT 
on.M-„^-rtionuro,u-erned with special hahft, fh« 
in.porunt it Wome« for da^sitirE. A . !? "'"'* 

< »wfn in noeakino- of n,^ '^''"ration. As an lUMtanee: 
tn, innpeakin^of theduifon^', Mavn, ' Hie irennr-itiv.. 

*;? 5;rr'*'i"'^''^''«"""^'^trueatKniUeV UV 

'l.ere^ th. orpu,. „f ,epr<Klucti„„ »i,h their Lr^'.,' 
I." feed. ;.r. of paramount importaiir, ■ "^ 

>U. mu.t not, therefore, in cf.mifvi„„ i,u„ i,, ,„ „ 

=^e.v :a;^rr?r "th'^ts-rs^vj^rirrS-r 

•; ' outer vrorld. Perhan^ from Iv ;1 *^ relation to 
.1 I cruaps rrom tnia rauae it hxM oarti, 

arisen, that almo.t aU natunUiHt* lav the^r«,u^t'sTr ' 

-"■7 throughout Ur^e'^^Tou'^ Z ^J:"'^^ 'Z 
^ijfaii uoen not UfUrniine i»v rja^f. 



"N niK (.Kj(;i\ OK >j.|.^ j^;^s 

"•a...,, to ' i;'"; ; '« -''"« '-^-'. - - i.-o.. 

valu.., ,t. rji ':. : "7'''>; "'♦• -""•• pl.VHolo,^ 
''••''''r;U, .,,7 ';'r :••'''** '■" ^"'-'y •i.ffem.L 
-tru.k .:, ■ h , fa.t 1 ^;r^-»^,^-M' "Ul.out U. 
'•"l-'-i .n t. nt • "VS''" '"*'" ''^">»'k.i. 
-''i -'f.... U. ^. t'Xe H ;"'V *"^7> -"*''"^- 

•♦.■iVH. t»ie tr.-iji.ra ,,r tl.» V 'i'lutlier work 

•'• cw;"t";''r.''';''l''^ -ti..tion. A, 

"'H' JTobaMv Hill Ha tV«t n ' '•'^^""■*^'"" ; yet II 

i'"l'<TUnt'..r^„i u hm tL '^^"'^•^l'"" o^he wru, 

or,^ai.. are o/hi^ / ,.1? , .^T '"""'''•"^^'V "^ *tro,.lu.c 
vet. or! i''hTr'*^ "^^."^ in.portaure 

the rudimentlAC • 7L -^^ ""*' '^'^ ^-P"te that 
nants, and certain r ^^V^''?-'*"" "^^'O""*? nimi- 

tHWM KuminanUandpf ^^ ti.e .Iums affiruiv be. 
^tr..nd V; he f . IXAT " "r'*^ ^'^"^•" ^ 






.iern,.d trum iwrts whirl, nuint 1« cunHi.IortHi ..fx.-r.. 
tndui^ l.l.VMHln^ nn,n,rr..iut., but «in.l, urn utnv.T- 
•allv ^i.lii.ift.vl a. In^hly »*Tvu,.a!.i« in the .leMutiu:; 
'■J«h..l,. t::,.ii|... iM.ri/i.Ui.c,., MhrthtTor notlluT. - 
-.1 .-I"-" |'.i>-M^o trw.n the iio.tnls to tl,o r.M.iith. i,.,- il.Hra.t.T,i.,vi,rdin^to(*w,.ii,HhichaU4,liit,.lv.i„ 
tMipi.>l.eH ..,!,..> r.',.l.j,..-tl.e iuJicrt.on o! tiioa.. ■!. 
"J the i.iH, Ml Marsu|.,.»l.s- the ti.ann.r in wiu.h t"h,. 
*in»rH of ,M.tH-t^ are h.lded- mere roh.ur .u . erUu. 
\l^>r ,,,,.,-e |.ul.esc,.i.,e on partiH ot the fh.^^t-r ,u 
»rraH..., .ho of the der.ual .ouTiuc. .1. ha.r or 
.^Iher., nuhe ertohruu. If the ( )rnahorhv ruhu^ had 
l*Hn .u.c-rc-d HUh feathers iuMead of hair, tin., euernal 
aiid trifling rharartvr Houhl, I think, have i..-, n c un 
ml ,\" :'^^"^^''^*^ ^ i.i.|.ortHnt an a.d ii. deter- 

m nu,^ he de.^ree o, affinity of th.. .tran^^e crcuur. to 

,n r "f "T '''' *" *"«M'^^'^^t' i" '.tructure in a:u uu. 
iiiternal and inipurUnt orj^an. 

r).« ini,.orUn.-e, tor cU.,ticatio«, of trifiuiir < hara. - 

•eu'ral other .hararten. of n.ore or le«.s ,nw.ortan... 
he Nalue Uid^'ed otan a^^e^mto of .hara. ter» ... verv 

r . .rkod, a .pe,:,eH may dei«.rt from iU allien ui Keveral 

-ru terw, both of hi^h nLy.iol.,^ic*l a,.l 

" aJ ,.o.t nniver^ urovalenee, aiid vet have u. in no 

iouhtwhire itHhoufd Ih5 rauked. Uenve ah,o ha 
'-;; .uund tlut a oL^ifi.atiou founded ou an ' .'t 

ijracter. boHever .mp..rUut tlmt may »hj, ba- alwav. 

■onl; !"'lT •''*'' ""^ '^*' or^uuuiaon i. universal), 
' . ^tanl. He .mpoi ^nceof au a^»?re^^t«of . hara. t*,r«'. 
e . i when none are unport^t, aTooe expU.r.., 1 ib.nk 
t^ KU sayui^ of knua-us. that the charactl-n. do not t,ue 
ti>e *renu., but the ^enu- ^vo. the eharac-U-r. ; for thi- 
•^vn^f «eem. founded on an ap,,re«iaUon of manv 
inun^ po.nt. of resemblance, too .li*rht U> he dehned 

i-rfe..t a.,d de^ra;ie^fl;^;; ^ ■:i;^*ut;:;i' w: ha- reuurked, 'the t^re^ittr numhc-r of tL. 



•I . I 

■' ^ * ^''\' *, •*^'*' '''-'I'P'.'r, and thus la,,-!, at oi 
■^1— .<H-atH.n. Itut «1h.„ ., in J-r 'nc 
'lurn,,. H.v.;ral only ch.,.ra'i..l (iovrer .'pa 

U.J,.„dnan.;P. / In- ra^o seen.. t„ ,ru. wt-ll t- i.lustr . 

I'ra.lically wlu-ii naturalists are at work tl,...- .1 
-t tn.u Me thern>elve. about the phvsXioa Val I 
o o .• .ara..ter. .hich they u^e in .jVriniri a -rui 
'.r n alloratn.u' a,>y partieular speeies. If tu^; "n 
■^ -^Kiracter n..arly n,ufonn, an./eun.mon to a J^ 
.'in.'-roflorms and noteomuMm to others, thevust 
•t as one of h;.^h value; if c.uu.non to .o, lesse 
""".her, they use it as of suhordinato value nZ 

) t e the true one : and l,v none more clearlv than hv 
th:a excelient hot^-ust, Au;,. St Ihlairr f e^^ 

-ararterH are alwa.^n found .-orrelated with oU^A 
t!'""ch no apparent bond of connertion ,a he S 
...veu-d between then,, espe.ial value is .et u them 
As u most .^rouj.s of animals, in.portant o^.^u,s, such as 
'j'--.' tor propelhn;: the blood, or for aeratin- it or t! ot 
"T i.ropa,^■itu.,^ the ra.e. are found nearly ni Vm C 
■^re n.ns.dered a. h,,hlv serviceable J U^^^^. 
u>ome ..roups or a.umal. all the.e. the mo.tim-* 
MO'Unt v.ta, are four.d to olfer ehararu-. o/ 
■Miite .suf.orduuife value. 

^boulVb.'';:?' ^''-l :"''^"--'"'^«^« ^'^'•'^»'<1 from the en.hrvo 
• e L 2''"'"' 7'l";'-;«"';- -it»' those derived from 
- ..: "'^""'•.'•'•-;';<-tn.ns of eourse include all 

,r ■; .'''*"'""■ '"' ;' '^ ''>' "" "'^'•''"^ "^'^''«"«. 


ore nnpnruuu for this purpose thaii that of 
■^n aiooe piay-^ its full part in the eoonomv 
i»-t K i..i.. „....;, .^'.roriL'lv .ir-ed ,.v tho^ 

"f" n.iture. 

■It naturalists, Milne lO! wards and A 


I i I > (icitiiin of 

trassiz, that 

.•fianitfeis ar^ th.' most ininort^tnt of anv in tl 



iUinialH ; and tliis dort 

trt'iL-rally befii admitted a^f t. ..„ 

.00.1 u'itli riowerintr plants, of vviiirh H 

rniR has vorv 
rue. Hie samo fact held- 

-Kiiis hav 

!«• two main dm 

(' l«en (ouiHled on characters derived from fh. 
rmKrvo._on tlm numher and position of the emi.rv- 


li'a\cs or cotyledotiH, and on tl 

i/i»Mit of tlio jilurinjle and radicle. I 

16 mode of «leveloj. 

n our di>.u«Mon 

Mi.ryol.,:ry, „e shall see why such charact.-r 
it)le. on liift vievr of claf.siri<ation tac 

i!:i:ihle, on liie vi 
le idea of descent. 

itly uiclud 

•< ai>> so 


( ) 


«■l■l^-sification^ are often jdainlv inriuenced \ 

i.iwi- 1,1 affinities. Noti 


■U-w.w a of charactt 
ui itic ca>e of 

nriir ca;i t,e easier than t. 

r-i tommon to all hird^- i»ii' 
crustaceans, such detin:tion h;is hitherto 
.-en found imyK.sH.h le. There are crustaceans at the 
"I'I'-ite end. of the series, which have hardlv a 
• t^ar.icter in common : u-t the s|»ecies at hoth end. 
from beuiiT plainly alll.d to others, and the,e to 
•M -er.. and so onwards, can he re^-o^nised a.s uneouivo 
al y l.elo,i^..n^ m thi.-, an.l to no other cla.s« of the 

'--graphical distrihution has oftei- heen used.thou.-n 
.'••r!,ap« not .,u.te lopc-lly, in classifioatior!, m.fre 
^-.ecially in very large groups of closely allied forn,- 
"•'"'""i.^k insist., on the utility or even necesvtv of 
'■■■> i-ractice m certain groups of hirds; and it has heen 
". '"v... t,y several entomologists and fn.tanists 

I inally, with resptxt to the comparative value ..f the 
w-riou, ,^roups of sj^cies, such as orders, sulM.rders, 
urn i,,.., .sul>-families, and genera, they seem to he, at 
■e^-t at pre,Hen . aim- -t arh.trary. Several of the l,e.t 
^-t•in.sts, such as Mr. Jientham and other, have 
^troniriv ,ns.ste.i on their arbitrary value. in.-tances 
UHild 1,0 ^nven amoni.-t plants and in-ects, of a i:rou,. 
■'!.,''"'.!: T.l ""•'^* ';>■ \"-^''^'-^'^ natumli-t.. as only i 

i'Milv and this has been <lone, not be<-ause n,r,fier 
^♦'-^e.r.-h has detected im}x> structural UiffereiK-<.s 


at first overlooked, but bix-au^naineruus allied ,,^1 
^'•h sh^rUVy d,rt-«rent ^^raden of d.fferen.e. l,a^iT>l 
Hul)s<>.(iH'iilly discovered. 

All Uie lorefroin^r rules and aids and diffi.ulties>:.hatiou are ex|,h.i,ied, if I do not cnatly derei 
■nvM-lf. un the vu-. that the n.tura! s;>ten» iAound, 
ondeseentwith modiiicaUor, ; that ihe'charartern whi, 
i.aturalist.* consider afl shonin;: true artinitv l.etv»e< 

inhentod ,rom a conm.on ^nMit, and, m m. tar, all tr, 

ihT! ' r m" " r'T^T"^^ ' ^''''^^ community of descei 
O' the hidden Inind which .uturalK.t^ havV Wn u, 
consciously Keeking, and not some unknown r.!.n . 
creation, or the enunriatjon of treueral proj -{,;„*,, j^„ 
th. n.,.,, tt.n,^ to.^ether and .separatW oojectn mu, 
or le.s.s alike. 

Hut 1 must explain my meanin^^ more fuliv. 
be .e^ e tiiat the armnyevu-ut of the Krou,« within 'eac 
«i.i>s, m oue Kubordmatiou and relation to the othe 

'ItuST'f.^..f'''^>' »^«"''^^^'K-1 i" order to I, 
natural , hut that the anwwit of ditfereuce in the ..-vera 
.Hinche. or ^^roups, though allied in the ^n,e decree ii 
'l-'d to the.r common pro;,enit<,r, mav differ ^^reatly 

^^h., 1 they have uuder^rone ; and this ii, exi>resse< 

•y the (orms bemK ra,ike.l under different ienera 

am.lies, seet.ons, or orders. 'Hie reader wfll 1 

mder.stand what h meant, if he w.ll take the trouhlt 

o reternnu to the diagram in the preliminary. U 

w.ll 8up,.o.e the etters A to L to represent allied 

genera, which l.veddurintr the a nd th^ 

have descended from a species eJi.t vi a ta^.^ 

k n..wnan en..r penod. Sp,vie« of three ol dies.- ^^n^ a 

i; , ; VJ ''^ ^'■^'-•'"'ittt'd modified de«oendant.s tx, 

the present day, repre.sented by the liftoeu ^en.ra (a^ u, 

^^.on he uppermost horizontal i;ne. Now all thel^ descendants from a siu^rle ,j^.„^ are re.. ^T 

-n,ed a.-_ related in bhKKl or de J!?!"-": ^r/M'::: 

<U-^T.e ; they may metapnoricaily Ik. called cous.nrto 

the .une m.llumth de^^ree ; yet they differ J.deJy 

<tf ■ K'^iinj.i^C'.i^-tt:;? ;,**«*-. 



^.^ld in different de^e«, from eaih ilie fon.u* 

lesroiideu from A, now broken up into two or TrZ 

ramJ.e. conHtituU, a distinct order from thone ,1.! 

scoM. ed from 1, also l.rok.M. up into two famiJ.*^ W 

can lh« ox.«t.n^ «{H^, dosrende.l fro,., A, be rank.-l 

n th.. .ame, H,tb tl.e parent A ; or tho^ n m 

, wah the parent I. Hut tlie eiLsfn.^ ^ernis ►-* „" 

k' .up{M.>e.i U, have Wn hut sli^htlv nw,dif,ed ; an i 

it *.ll then rank w,th die parent -»renus F; just i^^ 

"n^rl"' t\"';V^" ^*'"*^« ''^'-"^ to\s]h:n.t 
^enerft. N) that the amount or value of Uie ditfer- 
'•urcH l^tween organic bein^rn all relat^^d to e.uh other 
.1 lu. ja„.e decree in blood. ha« come to In, H'ie v 
hrftrent. Neverthele«. their Ronealotrical urraj^. 
mnu remaui. «tnrtly true, not only at the pre. 'nt 
' r^^'f ?"'' successive f^eriod of descent. U 
the ,„,.d.he<i descendant, fron. A will have inherited tlnu*. ,n common from their common parent^ 
will all Uie descendant, from i ; so will it be wij, li" 

; ;'>d "l? hT'^ "' <J«'-ridant-, at each «ucce"ve 
c^H d. If, h..wever, we choose to .uppose that anv of 
Uie descendant, of A or of I have l^n so much mo^ rted 
as to have more or le*, completely lo«t trace. .^ 
the.r ,.ireuta*fe, in this ra>.e. their place* in a naM,r 
cWMfK-ation will have been more or leCompl tj h o' " 
-a^ sometime- seem. u. have occurred wlh exist nj 
or^.-Hm« All the descendaaU of the ^eTn F ah ^ 
|ti. who e line of decent, are supposed t^ ha v'eh^n 
ut httle modified, and they yet VL. a IX "^. I ' 
IJut ti.u, c-enufi, thoujrh much isolated will still ... 1 
.t. proper intermedin po«iUon ; for' Tori; L^^^^;^ 
Hitenneduite iri character between A and I ^ ,^ n 
^'veral jrenera descended from the«e two ^n ra I 1 
have inherited to a certain extent their ch" r^-u r. 

tnaiiiier. If a bj-auchin^r dia^rram had "«» t-i.- ■ ^ 

and ooiy the names of the jrroups had lienwHUeTHt, 

uave ,r,ven a natural arrangement ; and it u, notoriously 


ON 'nn: orkjin ok spe( jk.s 


I ! 

-ot povsiMe to re,.re>CM.t in a seri,-., .,n a flit surfa.-e 
itio afhiiities which we diMuver in nature amongst th( 
'.euiL'.- of the Mame ^runj.. '11..!*, „n the view which 
Hold. iU' natural .system is ^.Mifaloj^i.-aJ ,n it. arran-e 
.nej.f like a i.e.i,;,rree ; but the d..:,^reeH of n.odit^ratu,, 
^•liuJ, the dilff/ent sjroups have underirone, have to hi 
'xpre^^Hd by rankintr them .mder dirferent rto-rallft 
-'en.'ra, sub- families, families, .ectinns, orders an.l 

It may he worth whil,^ to iiJuHtrate thin wew oi 
lassifiration, hy takiiijc the rase of lan-uaijr^ If wf' 
imssessed a perfect pediirreeof mankind, a trene^loincai 
..rranirement of the raot-s. of man wouhl afford the best 
.lasH.fication of the \anous lanj-ua-es now spoken 
throu^rhout theworM; and if all extinct lanjr.Kiiies and 
..1. intrrrnHiiato and slowly chan;,Mni; dialecU^, had to 
t»e mc udi-d, riuch an arranyen.ent would, I think be 
thf ..nly possible one. Vet it nn-ht U^ that sou.e very 
ancu.i,t lan-uaue had altered little, .I'ld had gneu ri.,i 
• ' ^ ii^vT lanirua-es, wiiil,t others (owintr to the 
-pieadin<r and subhequent isolation and states of civilisa- 
tion of the several ra. e,, descended from a common 
ra, e) l,ad altered ipuch, an.l had -iven rise to mariv new 
lanirua^es and dialects. He various decrees of differ- 
ence in tiie lariiriia^res from the vime stock, would have 
to !„■ e.vpre.sseil hy groups subordinate to ^-roups ; but 
rhe I-rojK'r or even only p„ssiblearranfremeut would still 
i>e «eneAlo;:ical ; and this would be strictly natural as 
.t would connect tofrether all Ian, ..a^res. 'extinct and 
.nodern, hy tl.e close..t affinities, and would ei;e the 
hluitutn and oritriu of e.i< h tongue. 

In .onfirma^ion of this view, let us -lance at 
ihe cUsMificution of varieties, whi. i; are !.»'lieve«l „r 
ni.own to have descended from one species 'Ilie^e 
i.-e irrouped under spvcies, with sub - varieties under 
• arieties; and with our domestic productions several 
other KT-yles of difference are re.|uisite, as we liave 
■tH-n with piLH'ons. The or'"!!', -.-.f :]:t: «TUt.-.=..-~. -.i 
w'roiijw Pubo'rdinate to groups, is the same with >arie\i&s 
^- -iiLh specioM, namely, closentMi of dt-Hcent with various 

'" " i II llililill I I II |ii|l|i|MIIMi I 



de*^.-.-i. of moiinratiori. Nearlv the H-im^ riile^ arn 
(oJowed in .-Lvsifvin;: variotjps, as with specie. Author- 
havf» msHlfd on the n.'ressitv of .la'^.sintr vanou.M oii - 
nalt.ral iiiHtoad of an artihria! «vKtoni ; wp are mu 
t:oi,P,l. lor n,.ti»ii.-o, not to .-la.,* two %ari..tieH of th«. 
pinf-nvple to-r>th.'r, mrrely \>ecHuse their fruit, though 
tl..' nv^t important jiart, happens to h.. nparly icientir.ii • 
MO ot... put., the Swedish and common turnips ti.irether' 
thfMi..., theeMuilcntand tiiirkened stems are bo sun. i;ir' 
\M.afvor part is found to he most roiKtant. is used 
m varieties: thus the ^rent aerirultur.f 
Marsfiall >ays the horns are verv useful for this puriMw 
with rattle l,er^u<e they are less Variahie than the 
-hape or .-olour of the hody, etc. ; whereas w,th sheep 
'he horns are much leM sernceahie, l^cause less 
•oi,.f;u,f In chssuitr varieties, J apprehend if wo had 
.. real i.ediiTTee, a <renea!ot:ioal <-la<v„irati<ui woul.i |... 
■niiv.Ts.uiy preferred ; and it has heen attempted h; 
->rne authors. For we mi^ht feel sure, wlu-ther tliere 
had oeen more or less modifi.:ation, the principle at 
.uhent^nce would keep the forms to^eliier which »ert- 
luied in the tm-atest numher of points. In tumf.ler 
piK-fjnng, thoujTh somesuh-varietie* differ from the r.ti.ers 
.n the important character of having a lonjjer »>eak vet 
all are kept totrether from having the common hahit 
■.ftumhlinir; h,.t the short-faced breed has nearlv or 
-juitehrst this; nevertheless, without any reasoning 
or thmkin^r on the suhject, these tumhlers Are kept in 
he s.->me jfroup, lM*oause allied in blood and alike in 
jome other resjK^ct*. If ,t could be proved that the 
Mot e.itut had descended frum the NWro, I think i.e 
-oiil.i W classed under the Nej^ro group, however much 
'" m.^ht ditfer m colour and other important chara. te- - 
"om n«*rroes. 

\J iti) «i»ecie3 in a s'ate of nature, every naturalist has 
H. fact brou^'ht descent into hi.s classification ; for he 
I'ldude. in his lowest ^ade, or that of a specie,., tlie 
•-'•- «~?es ; a:;d l;;r^ er,orijiousiy these sometimes differ 
ill tlie mo«t iniporuut characters, ia known to ever*' 
riSturxJirt ; scar.eiy a single fact can be predicated in 



comrno,, of the rnal.^ and ht.r.„aphrodu«.- of r^rt; 
r.mpHe«, when .vi.It, and vet',... one ,inZ7 

u.eMJvrral larval .t-wres of the Kame in.i.vid-iaj hole, 
.u,.h ,hev .n.v d.tfer from each other ar.d frorn 
ad.ilt. an he nk.-.vne mrlndes the so-.-alled alt.rni 
..-..era hoHH of >f.enstn.p. . h,ch ran onlv ,n a ' h "i 
-r,.e »H. ronsMLTed as the .an,e individnal 
unhide, monsters; he inrlude. varieties, not M.le 
.e.aa«e hey do.ely re.vMnhle the parer.t - f<,rm b 
H..aasethey •.redeseended from it/ H. who Miev 
t^.it the cowsl.n ,« descended from the primrose , 
••-'vorsely, rantcs them to.^ether as a s;,Lwe spe^.'e 
;'"i /rives a .uis\(. definition. As soona^ thn 
-h, oan f;.rn,WMon<,.-h.nthu«,"^:^ r^ 
<t im) had previously heeu ranked :.s thrc 
i-mrt ,'enera were known to he sometnnes prod c" 
"-he H.ame Hp,ke. they were immediately ir.e uded ' 
'« -it);,'^le speries, ■' 

As .lescent has univer<«illy heeu .:sed :n . lassi,, 

'..-ther the md.vdnals of the same .pecie.. thouH 

he males and females and larv* are somet mesex 

rcmely d.t^erent ; and as it has heen used in cWin have undergone a .ertan,, and «ome 

tmes a cons.deraMe amount of modification, mav no 

hH same element of des.ent have been unconsc.ou 

u>. i .n ^ spenes under genera, and ^ener 

.H. er h„'her groups, though in these case, the modi 

hc.uion has been .^reater in decree, and has taken . 

<..) tm,e to con.plete? I believe it has thu!, .eer 

u u-onscously used : and only thus car. I unde.-sta.'d 

Uu. several rules and tjuides which have been followii 

bv our bes systematists. >Ve have no written pedt 

Kr.e. we have to make out community of descent bv 

resemblances of any kind. I-herefore we choose those 

ha a.ter. as far as we can .iud..e. are the l^ 

l.KHlv to have been n.o.iitied in relation to the c^ 

H.t.ons of l.te to which each .pe<-ie.s has been rll.rZ. 

'•^,i. Kuu.meaury structures on this view are a^ 

t...K. ,. or even sometime- ^»etter than, other oart. of 

^f^^»l':fPr? f.?ir.£^B!»ii2BK- 



thf o-sfnni«<ati(.M. W'e c.%ro rmt how friflinp n chamcter 
HMv tK» let It }>e t!.(. ,nor.> iiiriortion of the ,-»n-l.« of 
' ^<' Mw, thp manner in which an iri^prt'«« winjr i„ f„id.-«l 
••'•h.«;h«T thp skin he roverwl hv hair or fj^athfr** if it 
t-'ovul thro.i;:hmit manyan<I different Hpocips, e«m.riallv 
tlin.e h:i^u^tr very diff.-rent hahits of life, it a-ume;. 
'i_'li value; for wp rari account for its presence in 
^' m,.ny forms with mi.h different hat-its, .mlv l.y it* 
irihmt.inre trnm n <ommon parent. We mav err in 
!liw in n-Tird to single points of structure hut 
^*h.-M -evor:.! chara.ters, let them hg ever .o trif'iinir 
nr,=,r tr.L'otlier throuffhout a Iar<re oroup of heininJ 
hv.-inir ,j,ff,.rpnt h.ihits we may feel almost sure on 
the thoory of descent, that these charact.-rs have l,,.en 
iiihonN.,! from a common ancestor. .\n.l we know that 
iurU corrHatcd or n--re£rate<l characters have 
>il :t» HI classification. 

^^'e can undersfind whv a sj.c. ies or a L-roup o» 
^i'cr),., may depart, in several of itj^ mo^t important 
-liY '•;»>n,tics. from its allies, and vet he safely da.sed 
«"h twem. Hii, may he safely done, and is otlen 
dorio, as lon^ as a sufficient numher of characters let 
tl;<:ii i.e ever so unimportant, hetravs the hiddeji h'nuH 
Of CMmmunsty of <iescent l^t two forms have not a 
s)iirJe character in common, yet if these extreme forms 
•vo connected to-ether hy a chain of interme-jiate 
I. " ips, w.. may at once infer their community of 
'i' ■';ent, and we j.ut th.-m all into the same d.xss .\s 
'-find or-:u.< of hiirh physioloLHcal importance those 
'- ■•uh .ene to preserve life under the most diverge cn- 
•f tiHPs of eiiHtence-are ij-enerally the most con^-ant 
«p .ittach espe<-ial vaLie to them'; hut if these <ime 
•T.Mns. in another -roup or section of a jrr„„p, are 
'«• nd to differ much, we at once value them l,.<s in 
<"^ rlx..iticat:on. We shal' hereafler, I think, clearly 
'»»• «iiy emhryolotrical characters are of ^„ch hi^h 
!!!r.''l!!!!.'^.?'Z ^'J^P"''^'^'=7- <'P<5raphical distn hut-on 

.n?.K "inTV.-':,..^ . ..^U^ ..^^^.^ij^ -^^j^^^ ^.^^ .^^ Cia>MMff 

■^r^a and w-dely-distrihuted ^renera, liecause all the 
•'.K ie« of the same ^ntn, inhahitinr any di.stinct and 


<'N JJIK OIUtilN OK Sl'i:(:if>;>yi rv^um, havo in all pruhabilitv dt.«,-e.i.Io.] f 
iJiH R.Tm<' ji.i rent's. 

^W ran uiif)<'r,Uri.], <.n thcsp, tlie very 
P'.rtyit ci,>tin. lion iK^twr.-n real affinities and analo- 
o- ri.,a|,t,ve ro'-pnihlancrs. Umarck first call.-.l at'i 
f.oi, totl.Kd.stin.ti.m.and l,e has Uevn ably loll..^ 
U} Mar.iMv an<i (.thrrs. Jl.e rrM-mMance, in Uw «I, 
o< << o }.,..iy an.l in the fin-like ant/^rior liml-n. hotw 
h- d.urone. which is a i-'u la .Irrmatuuii animal, i 
t'M- « half, and hrtw.en hoih l[,.-.e mammals and fisl 
1" ;<,Ku-al Amon-.t iiiMTts thrre an- ininim-r, 
mstarices : thus U,ui*us, misled hy external hi.,,. 

atn-es, a.-tually da i an Inuiiopt'erous in^vt '.. \\ ,. M>e ^.)methin>r of the same kind even 

...,r .lomestir, as in the thirkened ^tcrn. of l 

enmmnn and swr.lish turnip. n,.- r.-M-mhlance of 1 

Knyn.MHHl and ra.ciiors,. is hardly mure fanciful tli 

the analogies whirl, have heen drawn hy some auth, 

hetweer. very .]i^tiMt animals. On mv" view of d., 

acl.M.- .em^r of real importanee for . lassification, oi 

in so Mr HH they reveal we . a-i rlearly und( 

fitan,] ,vhy analo-iral or ad.n-♦i^e rharactor, althou 

oi tie utmost iirij.orUnce to tlie >velfare of the Umii 

are aiiiiost val-ielesa to the ^\ .lernatist. For anima 

'"'i'm-inir to two most di> lines of decent m 

r.adiiy heeome adapted to similar eonditiou-. and th 

ass.nne a elose external n->emhl,in.e ; hut such t 

semlnances will not reveal will rather tend to conce 

their blood-r.'lationship to their proper lines of d.' 

ne .an al<o understand the apparent paradox, th 

ti.8 v..ry ^mv characters are analotrical when one cla 

or order is .-ompan.,! with another, hut trive tn 

ntfiiiitu- when tiie members of the same class or onl, 

are compared one witii another : thus the shape of tl 

body and tin-Iike limbs arc onlv anal-.iric ,1 when whah 

are comj.arcd with fi>hes, bein^- a.lapLations i,, hot for 8wimnnn;r through the water ; hut the shar 

!!.l,l.!w;. ?^/ *"•',, '""';J'1^»^' l'"'>'^ w-rve as rharactei 
. v .!■!!. !!>.|r r:;e -^i; . . . _ !^.^. y^j..^_.^ .j^^^ hcv.Tal mcmbei 

ot Uie wtiale family ; f,,r Uiese cetaceans ajrree in i 


?-*i -- t-"!'-"! 



tMV c-Lira.„-rN. ^n-.-.t arid Hrnall, that 

<l«".!.t that tlii'v fiave „ 

"«'.lv aii(i -fnirturo of limf.s'f 

'*^<' It i.s witli fi.sht 


nUi-raed their ^etu-ral sha,K, of 
ntni a rornmoii an. ,.!»tor. 

\- rnt-niherM ..f .iistiriot .lasses* h 

l;i|it>Ml iiy mj 


ia\»' oft^'u I 

I'Mrlv -iniihir finiiin>t 

'<li4rht nio.lificatioim to 1 


trie tliri'»' el»' 

"MTS.- to ililllhit f, 


i|iM iiinl«'r>taii(I } 

I'-iitxot iaiKl, air, and 

i\«' iinihr 
T iri«itaii(p 

"w It is that a ri 

ha> •.orji.-iuin's l,i.,.„ obs,.rve<l \,v{ 

111 <ii 

tirirt .lasses. A Mafuralinf, struck \ 

watiT, H-.- can 
"riUTical parall».f|^rn 
w»Mvi the •<iit>-urniii»- 

"f this naturi' 

or vi,ikiii{r t)ie val 

any one cla>s hv arhitranl 


ot tl 

'»y a |..iralirli>rii 
y rai^iiiir 




lia» liitht-rto fteen art 
I'.iralleli^ni owr a w nie ranir,. 
Mi'i"-»ry, .luateniary, and h 
proi.iMv armen. 

iM' irrou{w in ,,ther <1 
[.enenre ^hov*8 that thn val 


arbitrary,), could easily extend tl 
and thus the -«'}iteiia 



■rnary cla.Hsificati(»ns } 




As tl 
■'"iiirin:; to the lart.M 

!•' moditled descen.lant>i of d 

oniinant species, 

advanra^re^, which n.;.<if tl 

r >r..„era, tend to inherit t 


'"iir iar^e and their jiarents d 

'♦* *,'rnii|,s to which th 


aiiiMisf «ur;' to in the ecor 
and n 

pread v idely and Ut sei 

ominatit, they are 

/e on nuire and 

iiore dominant trrouj.s thus tend 

""iiy of nature. The 1 


int' lu si/e; an<l they < 


■'Her and teelder 

'i •• fact that al 


III' hided und 

er a tew 

'•> K«» •>ii increaj- 

•onse,_,uently supplant many 

Hi account for 

extinct, are 


liiis we c 

or^misms, recent and 

<-l.t-ses, and all in (> 

*rreat order-, under ntill few 


h<.w few the hi.rl 

♦• trreat natural nyste 



f ..« widely spread thev are tl 

tfJier groups are in numl.e 

As si 


'•K't i> >trik 

iiiif, that th'e d 

irout'hout the world tl 



n the ve-etahle kiiiirdom, as"? \ 

ii'^uiyle inject helonjrintr to 

iM-overy of Australia h 

IS not 

a new claMH ; and that 


las addi'd only tw 

111 the chapter 

<> or three oriiers of 

earn fr<.m Dr. Ho«.ker 

on jfpolojrical «ucces.sion J 

small si/e 

t-l<..w.on thepn;;::;,K::V::::^' « J attempted 

-; -..i nun.h [n character iluri;;; tL:' i:;;;;:.^:; ■::l!i 

■— ot mod.t,cat.o„, how it i. tliat the nrore anaeu 




fnnnH of life ofton |,n»stMit rl.ara.terH in somo si 

•ijvre*, mternuMliato Ih^Uvou ex.sti.iif ,fro.j,m A 

ol.l and ...lernuMluite pan-i.t-forr... hav,„^ o!-. asioii 

trainnnm..! to fl... pre^,.,., ,|av .lpsr,.,i.lanU hut 1 

in.Kl.h...|, will K,vo t<) us ou'r Ho-ralle.1 os.ulan 

aberrant jfro.ips. -n,,. m«.r« alM-rraiit anv form is 

trn-atiT jnust Ikj the .nuMher <.f .-o.ine.-titi,^ forms wl 

on my tli.-ory have heen exterminate*! and utterly 1 

Ami we have evidence of ai.errant forms ha> 

Hurfere.l severely from exti.j.-tion, for they are i^ei 

ally represented hy extremely few s,KH-,e; ; and s 

H|M.nes jis d*. ocTur are «:enerallv very distinct fi 

eacli other, which ajrain implies extnu-tion 

jreneraOrn.thorhynch.i.s and J^.pidosiren, for exami 

would not have heen less aherrant had ea.-h h 

represented l.y a d(.zen Hpecies instead of hy a sin 

one ; hut such richnos in sjM.cics, as i find after ,*, 

Mnesti::Ht.on, does not c(,mmonlv fall to the lot 

al.erra>il jrenera. We can, I thii.k. a-.-ount f..r t 

Jact only hy hu.kinir at alH-rrant torms an failijiif jrroi 

««n.|u--re.i hy more .successful comi)etitorH, witli a I 

mem hers preserved hy some unusual coincidence 

favourahje circumsUmces. 

Mr. Waterhouse lias remarked that, when a memi 
UeUmaiun to one ^roup of animals exhihit^ an affin 
to a quite distinct irmup. this affinity in most» 

ireneraland n..t s; ,a] .- thus, accordi'njr to Mr. Wat 

house of all Kodents, the hi/cacha is most neai 
related to .Marsupials ; hut in the points in which 
approaches this order, it.s relations are general a 
iM.t to anyone marsupial s|»ecies more than to anoth< 
As the points of afh.nty of the hizcacha to .Marsupij 
are helieve.l to Ihj real and not merely adaptive th 
are due on my theory to inherifm.-e in commo 
Iheretoio we must sup|^se either that all H.KienI 
including the hizracha, hrandied off from some ve 
ancient Marsupial, v. Inch will have had a character 
some d..irree intermediate with respect to ;U1 existii 

M.J— :..i 

i-otii ilo.ients and Marsupia 

l.ranched off from a cmmon pro-.-nitor, and that 1m)1 




trruupfl have sin 

ilivertfeiit direclio 


•-e uii.lerK<tn« much mo.lificat 

lat Uio I 


o c 


iia I 

Mn. ( Hi eithor vi«w we 


loti in 


of its at 

retained, \,y inheriLa 

niay Nuppu^e 


"re, njort} 
than have 

"....-. .M„,e,uH; an.l therefore it w,ll not he H.H'ciallv 
niate^ to any one ex.stin.^ Marsupial, hut i.Inv • 
.all or nearly all Marsupials, fr.'m hav.n^ ,«r in - 
reu.ned the character of their common proje nfo ir 
M an early memJ>er of the »f roup. ( )n tl e oSe hand 
of all Mar«up,al.. an Mr. \\ af'erhouse ha. r^n a i^t«, f.uf the L-eneral order of HodenLs. In this 
.ase however. ,t may Ik, strongly suspected that the re 
M.,Ml.lance ,h onlv analogical, owin^ to the .„ '« 
Kiunjfl,e<-ome adapted to h.hi.s like those >f « {. ^nl 
e elder l)e ( ando Je ha. made nearlv similar ohserva. 
.1 . .s on the ^.eneral nature of the aHinities of d.s^mct 
oniers of plants. "isnnti 

<>!' the principle of the multiplication and ifra<lua 
'iivereenre ,n character of the spe, .s de^cende^H mr 

'■erit-uno of some characters in common, we can 
iHiderstind the excessively comnle* ,,..« .^a r 
acuities by which all the nLZr!; ^^if 'L^tmij': 
"r h,^her ^roup are connected to^.ether hort/.^ 
'ommon i«rent of a whole family of s,K.cies n . 

un.npH, H.ll have transmitted some of its characters 
■n..dified in various ways and det'rees to all .?A fx ' 
.^veral specie, will cc;,uenrry Te' elated "'each 

other by c.rcuit«,uH lines of affinity of v..ri ous len'Th 
- may l.e seen i„ the dia^^ram so often re er e Vo 
-Hintmjf up through many Predecessors A it s 
•^^ou^U^^\ Hlood-relationship l>et«tn \i:^ 

.•;^^ 7. fi J"*^ ^^ ""'y ""'^'^^^ and ""''>« family 

•uL! I r "."^ l^- * '^''""^J"^^*! tree, and almoin 

'.■M>Oss.Me to do this without this aid. we car. ..I.Z 

- -.u uie extraordinary difhcultv which natur'ali ' 

s af!initie« which they p^-neive 


ram, the varion 




h«"tw..pri til*, manv lu;n^' mihI ..xtiiict nu-nih«r« ..f t 
»*atii.« irri'.it II cl.i-s 

Kxtiii. t„„,. a.«* >».. h.iv.. K,.,.ri in the fourth cJnr.ti 
l.;i- jnav.-.l at. irn|M,rUiit j.irt in .l.tiniriu- aii.i v*i.l,.„r 
tfi.. Mi(> U.t«,.,-ii U„. M.v,-ral ^rr...i|.s in ...i,l, , U 
^\.• tnay t),.,., a-vouiit ,.v.-n f.-r th.. di.-tiMctn..^^ 
v.h..l.« .•i,,s.».M fn.m .'.,}, ulh..r f„r itmtam-e, ,.f 
from Jill otiier v,.rt.-t.r.if«« auniuiU-- l.y ih« |„.I ..| tli 
matiy aiicifrit f..rtn> of lite },ave Im.,.ii iitti-riv 1... 
tlir..u-l. Hhioh tl... rarlv,.„itoM of l.inU w,. 

tortiM-rlv cniMMMti-.l witli tl .,rlv pru-.-nitorn of tl 

otlMT' ( I.i^m.m. I h.-re I,;.. l,..,.„ l,.,. ^„t, 
.•xt.rutio,, of tl,,. form^ of lifr «f i.h ..ii.« roiiiMMt. mtl, l.;,tra.-hiat,s Hmto I.,., I.,.fn Htill le<- otlMT .•la^>.-. as i„ -f fl,.. ( n.Ktami, f( 
h.T.' the nio^t w..ii.l.Tfully diverge forrns are utill ti« 
toiT.' by a lot,-, but hroken, rhait. of Hffi.ufie 
hxiiH-tioii has oulv Kfparati'.l trroups : it ha.s l.v i 
riM-uis n.a.l,. tliern ; for if overv for.n whi, li lia^ 'pv* 
live.l oil tlii^eartli woie Huddeiilv to thoutr 
It w«.ul.i 1... .|uito i".po^«iMetotfivfd..tiiiitioii. I.vwhi.- 
each ^rroup rould Ik; .li^tintrui^lied from otlu-r trrouoi 
as all w.uil.l »,l,.,..l toirethfr l.y >teps ax fii,« a« thu. 
between the tuiest existiiiir varieties, iievertlielevs 
naiiiral rlasMficatioo, or at least a natural arratiffe 
ment, wouM he po.*ihle. We shall see this hv turnir. 
to the .liHirra.n : the letters, A t.. I., may represe,, 
♦'lev en .Silurian jfenera. Mune of v,hirh have priKlure irroups of rno.iitie.l <les,-en,lantK. Kverv inter 
n..-.liate link U-fween these eleven irenera a.i.l the! 
prin.oriiial parent, and every intermediate link m ea.1 
l.rainh and snb-hrar.rh of their de.rendants, may b 
Mippose.l to he still alive ; and the links to be em riiiea 
those iH-tween the finest varieties 1,, this .-ase it w„ul. 
he .juite iT,.i«..Nible to irive any definition by whi. h th( 
^everal members of the several -roups rould Ik" diK 
tiiijfuisbe.l fn.m their more immediate parents • or tbes, 
ua:enfs from their ancient and unkiio.Mi proL'-nitor 
^.t Ti,e u.ilurai arrati-emeiil in the diairram'would ^til 
hold Koud ; and, on the pruidpltj of mheriLancr, all thi 

^-. V 4,' J' 

■ v-- 




•t th« 

f,,r-M« .l«T.«ii.lwl trnm A, ..r troni I. would linvf* h4m„»« 
'iiili;: ,11 ((inuimu In :t iri'i- wh,.ui -(.frily this ..r 'h:tt 
iTaii. fi.thiniifli .It tlii'ri. liial furk tJu- two unit;- an.l Mt-id 
?i>L'»'tl,..r. We roiiiii iiDt, .1- I lian. sanl, .|#,t,t,,. thrt 
■■••\» i:ruii|H ; t.ut wf> (•••■iM pi<k out tv|..'«, ur tcrini., 
r.-pr.>-Mi!iiur most of' the rh.irart.T- i.t .-ail, t'n.iij,, 
-ii.'ther lar:;.. or -irii.-ili, itiui thus jfnt* a tM'ti.'r:tl uli-.i oi 
■h« kftlue (>( tl... (liif,.r.'iir»'H hefwren thi-rii. 1 hi>. h w hnt 
«e Khi.iiiil l.e.lriv.Mi to, if we were on.t Uxiiir, ♦M'd in 
.••ill.'.tiinf Hi) tli». »orm« HI any cla^^ ^Uuh ha\e 1iv»hJ 
throii-hMiit nil tiriii- aixi «(.»<•♦•. \\ p »h.ill tertainlv 
iifver Mi.(»'»>d in niakirnj ho fKTfe.t a . ollf.-tion : rif^er 
fh.'l..^-. in rtTtain . ia«M-, w« are tetidunr m thii 
'lire<tu);i ; and Mihir K.i*» hns lati'lv inwistpd, iti 
an al.le pajx-r, on tlio lujfh miporUnrp of lookintr' to 
typi's, wii.nher or not »e can -.pparate ami dehne the 
4fruii|n to which ttuch ty{>et» U'lotn;. 

finallv, we have R«»en that -eli'. tion, whi.-h 
rPMilti* from the htnijfjfle for exiM»-iK-f. and whn-h 
almost in.-viiahlv induces extinction and divtrtfence <tj 
charH(r,.r m the many descendants from one dominant 
|mr»Ma- species, e.x|ilainij that trr.-at and univer^l 
tc.;iiire in the affinities of all organic l»ein*:«4, namely, 
their HuiM)rdination in jfToup under jfroup. V\ e use the 
el'-ment of dt'srent in clan^intr the individual of 
wxes and of ail a^es. altliouiih havinif few characters in 
cc'i.mon. under one s[.etie8 ; we U(«« deM-entin cla-oflin^ 
a-knowledued varieties, however different they may 
h«» from tlieir parent ; and I helieve thi- clement of 
d.-sc.-nt !•* the hidden bond of connection which riaturAl- 
Nr> have soiijfht under the term of the Natural Sytcm. 
( >n 'iiis idea of the natural system heiii^, in so (ar ait it han 
I'Wii |K'r!ected, i^eneal<»);i<-al in its arranirement, with 
the ifnide*i of dirference l»etween the d»*scendant.s frnrn 
i common parent,^swl hy the Utiii-. ir„,K.ra, 
fimilies. orders, etc., we .an underbuild the nileJ 
J* nch we are compelled to f.dh.w in our datsitiration 
•- - ra:: .i;:!urs:a;i'; ^fiv «« »ainr certain re-.«'miiiance.i 
fflr morf than others; why we an- j^rmitteu to u-^ 
rudiuient^ry and useless organs, or otiier*. of trifiiriij 




"N THE OK M>K(lK.s 

-'I:,,; ;,'::r;':,!::;.:T;:L;rr;r::::\r'-' -"'t 

< i«MrIv SCO how It H tilt all liv;,, j ' • ' *^ ^ 

. ^era! n,ernl,er>o, ea.h das. are n-niXil n^ l 

look to some unknown plan of Coat .mw. ^1 v 
f" ",ako «ure hut .lov,- pn^ress. ' ""'•' ^'"i 

I .11 /I (Uii(>r ij, (dp orpfn.ral '1 •1.1 «f »l 

«nr. au.i for^r . ' ,. ,1 -^-y"*-. ' '•^ f-n.. of the;;:,;l;^:!-.-'.';;;;t-n.j.^^^^^ 

^"•"•^^^, w.ioly ,i>tf.>r..,u ani,n:.i. \\> s '^ I,'' 
^r^ .aw M th. .■o„>tr,u-tion of th. ,no:th".nr """ 



I nco^nff 

"pnJ^''"""/'**^"7^'' thar. the \mn^'n^.vU U,.. 





ot.<> of a \*op, or l.ui:, and the trn-at jaws of a l^M-tle?— 

■ ft al! t}ies«Mirtjriii>, scr 

tre forriie<] l.v iutiiiitelv t 

viiijf tor such (liffiTfut 

iiinieroim nwHliticatioi 


IS ot 

m upper l:p. maii.iil.Ies, ari.l twr, pairs of maxill* 

\!i.i ..-oijs lauH co\eru the r.,rmtru.fioM oftlu' n.-.uths 

Ami lirni.s ot rrustareatis. So it im with the tlowpr^ of 


Not hint' can t.o rnore h..p,.!e<s than to attempt to 
e^:,la;ri tMs similarity of pattern in memhers ot the 
virno .liN-. hv litihty or by the .ioetrine of final rausc- 
1 IP hope of the attempt has hcen expressly 
lm:;te<l hy ( hv,-,, 1,1 his most interestinjr „„rk on the 
Nature of l.iml.,.' On the oniinary view of the inde- 
i.eM.leii^ rreation of ea.h heinir. we .an f.nly say that so it 
•' ; t/iat It has ^o pleased the ( reator to ronstnict eaeh 
inni.'ii and plant. 

1 no explanation in mp.nitest on the theory of the 
natur.'il heleetion of su.eessive sliirht mod-firation« -~ 
'.i.'h mo.iifi.ation henitr proriLihle in some way to the 
"H..|:ried form. t„jt often affe.-tinjr hy correlation of 
-n.wth oth.r parts of the ortranisition. In ehan.'es 
'" t iis nature, then- will he little or no tendenrv to 
"H..!ity the on-inal pattern, or totransi,ose parts 'The 
"01,.., Ota lirnl. mi^rht he shortened ami wideiM-d to any 
•'xt.-it, ai,d h.-.ome -nidunlly enveloped in tlnrk mem'- 
r..i e. so as to serve as a fin ; ..r a uehhed f„ot mi-ht 
■ iv-' all Its ho;ie<», or eertain hmies, lenj^tleiu-d to anr 
.•\',.nt.and ti,.. nu-mhrane roiuuvtini: them inerea-ed 
;■' .-.riv extent, so as t.. ,erve as a w,,,^ : vet in all th,. 
-rr.r amount of mo.l.ficai.,,,! the:.- will he n.. tendenrv 
'n ilttr th.. framework of hon.-. ,,r the n 'ative .-..n- 
ne.tion of the several part.«. If ue suppose that the 
.v,...nt pro^renit..., the arehetvi.e as it mav l.e ....Ij.d 
"• .'ill nwunmals. had its liroh- eonstriirted on the 
-M^tiniT irener-il pattern, tor wl itever they 
--ved wecanatonee perreive th.. plain siir.nfiratiof, 
he eon-tru.tion of the limh> thr.uiL'hout 
: wHi..,. .i..„ >„ „,tj, jjjg rnouth.s of ifi.serts, we 

ivp nnlv to swppo-e that their eom 

• I i-er lip 

p, Jnatu 




on proL'enitor had 

ivo p»'.-H fit nin iiili*', 'lic-e 




ON TFfK ()Rl(;i\ OK S|'K<'If:s 

. . ) In 'l..MiouM,„^or,nultipIi,ati,K. of otlu-rx 

:'i,.';:;",T;,',ir,'-"' '"-" "■ '••'- '■'-■■ "-> >•■•.-; 

^ _ «r. ..tioii. \V hy sIk.iJ.J t)ie l.rai,, 1^ ^....1..... 

onii,";^'V'"'"'r'' ''''"'''' """"•'•■""* and ^nrh'^x^r^ 



the iH^riP'it .ierived horn the yielding (.f the He.«rat« 
mm's iti the art of iMrturitidij of maniinals' "I'l 
hy no m.'arn »'v|.l;iiii tlie s;iine fonKtr(icti(,i] in tht. 
-kull^ of f.inls W hv should Huiiilar hoiien have !«.,., , 
: .■roat,-<i in the formation of the ■.viiijr and h-y of a t> it 
M.fd a< th«v are for Mich totally difforPtit purposes ^ 
VVhv -tioiihl one crusta.ean. whicli han an .•xtrerocir 
omph-x mouth rornif<! of inanv j^irts. .■on-v-pa-ntly 
alw.iv, havef..vvpr let's ; or cronvers,! v, iho^ewith many 
Ifrs have simpler mouth^ ? Why Mhc.uld the m-i«1h 
r..'Mls stamens, and pistils in any individnal fiov*er' 
.hunu'h ntrpd tor such widely different he all 
i-onxtrinted on the ti«me uittern r 

< >n the heoryof natural sele<-tion, wo ran nati-fa. 'orily 
answer the^e questiouH. In tlie vertehrata, we nee a seneH 
of internal vertebrw hearintr ceruin pro.e>ses and appen- 
datres ; in the arti.-ulata. we see the hody divided mto a 
•eriei of segments, hearni^ external appe'nd.i^es . and in 
flowennt: plants, we see a series of spiral 
whorls of leaver. An indefinite rej>etition of the same 
part or ortran is the common characteristic (an Owen 
hasohserved)ofall low or littJtvmodified forms; there- 
fore we may readily helievethat the unknown proireuitor 
of the vertehrat-1 {M)s.sessed many vertehr* ; the unknown 
pn.L'enitor of the artieulata, many .eifment^ ; and the 
iink.iown pn.ireuitor of fiowerintr plants, many spiral 
whorls of h^ves. We liave formerly seen that parr.s maay 
times repeated are eminently liahle to vary in n.iml^r 
am) structure; consequenUy it is <juite prol«hle that 
natural selection, Hunnsf a lonK-<-ontinue<l course of 
iiiodifi.-ation, should have seize<l on a .erUin oumherof 
tt.e primordially similar elements, many times rer)eated 
and have a.iapted tliem to the m<.st diverse puriKws' 
And F.. the whole amount of mcMliriratiou nil! hav.- U-en 
.'tfe,;te<l by slijfht successive steps, we need not wonder 
at discovering ,n su.-h j«irt« or ortrans. a certain dcKree 
of fundamental resemhian.e. retained hy the str..nir 
(iiiiuipie i»r inheritance. 

In the Kreat .lass of molluscs, though we can homo- 
n>iii^ the part8 of one specie., those of other and 


:vj i 


lo^.os, ,s. wr. rxre soldcm er.ahled to sav that 
I-art or or,.u, is l.on.„|,,,on. another in\he 
•"'J;;"'"al- Am.I can un.i..rst.ui.i thi. Lt f 
rnollusrs even in tie lou-est memherH of tl e -las 
do not Uud nearly so much indortn.te repe i 'on ,? 
one part. a. «e tin.I in the other .^reat'cl ul e f 
animal and veiretAhle Irinjrdo,,,. 

Nat., ralis.» ,re,,ientl.v .peak of the skull an torme 
mef.morpho>e.l vertehra- ; the jaw, of orah. J ' 
morphose, le«^s the stamens and pisti W H^we 
. etam.rphosed le^ives ; hut it would m tnese canet, n, 
ablybemorecorrert. as Pn.fes.sor Huxley has rerTJ 
to speak, hoth .^ull and vertehr., Zl 'Z^Zl 

o he" r '7 '•'"' ^^^" '"*'^'''"^"T>hosed, not one , 
otfie., hut from Home common element \a> 

f'euse. tiM.yare far fr.m. meanin^^ that durinir a U 
<^ourse ot descent, prin.ordial organs of any k nd - ve 
^r* .n the one case and l.^m in the other- ha eartu 
-en mod.hed into skulls or jaws. Vet 'o 'trou^ 
the ai.pearance of a n.o.ii.icatinn of thi. nat" reZ' 

rrr'^'')!^''' "•■^t.-l'-'-'J-t^ -•»" l-rdly avoid emVo; 
Im^u:^^ havM.^r ,hi„ plain si^rnrtcat.on, ( )n ,n v 
hese terms may be used literally ; and the won^ieV 
-ut of the jaws, f„r instance, of a crab ret..mi 
.Hun-roas characters, which the • would prohably 
rctanHMl through .nheritance, if they had real l" be 
.eLamorphosed during a lon^ co.rse of . esce 

''■"m trill 


■i^s, or from some simpie apf^ndaife, 

fi,,.* '/ • -iirc.Kly t„.,.ji casiia V remarki 

Jl:,„-K "'■?"'' ,»'■"'■ '"'■■lilfiTem |,„-,„,« 

>..COt,(.i ,. "■■t'li..,,v .f,on,„.,rt<.l.r..>P.i„imj 


t.e cannot now tell whether it be that of 
Mnl or rei.tile. H.e vermiform hrv^ n 
iKH-tles, etc., rewrmf.l.. Pach other much 
'•lan do the mature insects; h 


a mTmrriai, 

flp of mothH, Hien, 
more closeJv 

; but in the case of larva-' 

, 1 , 1 , — ' '->- ••• ••«'»- \nifv or ia 

'-•» Imh'. of life. A trace of the law of 


, , "■ ••■^- '» "•*<«■ or tne law of »'rMbrvoni.' 

Srdl nf";;"' ^""'^^'"^''« J'-*^^ till a rather late a^e \h 
f- rds of the same KonuH, and of closely allied%enera 
'■•on re.enJ.!e each other in their /r.t and ^^^ 
I um.u..; as we see in the spotted feathers Z I 
thrush ^ronp. 1„ the cat tribe, most of the .ped^ a ^ 
>^ r „e<i ..r .potted in line« ; a;.d ^tr.pes can lie V>^in v 
li.twj^m.hed m the uhelp of tho lion. Ue J.Z . 
} thou^rb rarely see something of thin kind in pUnts- 
b.. the embryonic leave.M of the ulev or fnr/e and b« 
T' Tr: "^*''*' P>'yllo<lineouH acace;us, a «";;„"'! J ^^ 
.i.v.ded hke the ordinary leave- of the i;..nm!n ,:,. 
,,.u'r ^'IT"" '" structure, in whi.h the em.,rw.t of 
Hi Wy different animals of the s.ame da., r.'imb le 
•"•f. '.I.e.. often hav. no direct relation to the r con d 
-n,, of existence. We cannot, for inst;ui e lurrt" 
t»:at in the embryos of the verteb'rata the piculi; 1^ f 

:.4ted":r i ?^"^^r" "^^^^^^^ '-anS "u ':c 

[vh'^h ,s ^•""'•"J'0'"l'V'^n«. i" the voun,. mammal 

'of TT^T^ v" '''*• ""'"^ «^ 't«- mother, in the 

;, a . of a fro. under water. We he no more re.-us ,! 

.'t be same bone, in the hand of a man, win^ J! 

H an> Use to tb.^e a.-nnals, or are relafed n. fh 

'"■ ' -t.on. to «bich thev arc expL.d '^ ^" '^"' 

he o:..e however, i.s different when an mima] durnu 

^ I'-Tt of Its embr>-onic career is a.ti;e and bis n 

■ • V'l- f'T .tself. -n.e period of activitv ^'vl.ll'." A" 

•Hnivi;:" "1^ '", ^'"^ ' '■"* ''^'^'■'ever it'c^es";;n;th; 
^'•< • and a.s be,-.nt,tul a« in the «d.]? ..ui:aal ' » nm 


.".ijih -'.o, ,;tl adapUitKirix. the Kimilantv of tli.« l;irvi«. or 
H.uv.- .-.ihryo- <,< .,lli,..| .init.i;iU ij, irfi^H mwti 
<".s, un<l : an.l .ax-, .oul.i Jh- ynveii of tlw l.irv^ of Uo 
-|..-<i.... or of two ^rr,)i,[,- „t «|.r,-i.>-», .iirferiiitr .jiiite ;v, 
nuirii.r.rpv..M FMor*., from ea. 1. of 'it-r 'i.,-.!! .lo th.-ir i.iult 
|.arfnt-. Jti mo-t .Mses, hovviurr, the iarvH^, tl.otitrb 
u-tivf, ■,till (.l,».y, more or lesM , loselv, the law of com- 
rnoti .-.o'l.. .u!i:. reHiMi.M.iiue. ( irrificMlp^ afford a gnn,] 
iMstan.-,. of flu. : evt;ii the ilI.iMlrioim ( uvierdid ,H.t nr 
••eivetliHla harnacl.' w.w, rt« it .•ort^iiulv is, arn.^areaii ; 
hiit a irl.iii. .' at :ii,- larva >hows tlii.-^ to h«. tlio ra^e in au 
ntiiin-t.-ikahlo manner. So a^ain tho two uia.u divi- 
■^lons ,,f . irri|<, the pedtinnilafcd and HesMJp, which 
Infer wid.-lv in e:;!.>nia! ai.|>e.-iratice, have larv* in all 
their sUijr*'^ h.arel) di^tinLnnrihahle. 

Ilie eiiii.rya m the coiir>e of di-vflopinent »renerallv 
rise- in oruaiiisation: I u>.o this expression, thon-^i, 'l 
im ,iwar.. ttiat it in hanlly j.ossihle to define .hvtrlv 
Hhat IS nuMiit hy the orirauisation »>einjj hijfher or 
lower, lint no one pruhablv uiil dispute that the 
"lirtoriiy is higher than the caterpiliar. In norne cxses, 
H.^^tver, the mature animal is jfenerallv ronsi.iered .-J 
iou..r in the s.-ale than the larva, as wiiJi .ertiiin para- 
Hitic crusts, eans. To refer once .itfam to cirripe«les 
the larv* m the first Nfi^e have three pair^ of ](nr^, a 
very Hnipie single eye, and a proho-scilorni.-d mouth, 
With whuh thoy fee.1 lartfely, for they increase much in 
rtize. Jn ilie second Bta^re, answering tx> t)ie olirv^iJis 
statro of l.uttertiies, they ha^e six pairs of U'autifullv 
.•oii-tr... ted nafifury lejr*. a p^iir of matfiiitioent com'- 
p'Huid eyH.s,and extremely complex anteunH« ; hut they 
■i.iw i <l.)>ed and imperieot imuilh, and cannot feed • 
their tun. tion at this ^ta^fe i.s, to searoli hv their well- 
dev elope, i oPirans of -^ense, and to reach hv their active 
{Km-^^rs ot swimminjr, a pr<>{.er pla<e on which to I>e-. 
coni,. attu he.i and to undergo their final metamorphosis. 
n iieii this IS completed they are fixeii tor life: their lejo* 
are i,oH converted into prehensile ortrans ; they atrain 
oi.Uu .. weii-consiructtHJ moutti ; but they have no 
.in'ieui.«.j and iheir two eyes aro now rocuuverted into a 




■ iiriutp.Hirisrlp,an<l vcr\- *!mplpey»»-s[><»t. In this la-it jiiul 

ompU'tt^ staU», cirri [H»«le'« mav l»e 40tisi(U«n*<i a« ••itlit*r 

iiore hi^-^hlyor more lowly orirniii-^ni the\- wt-re in 

he l.-irv;«l roriditioii Hut iii sonu" trt'iiprji the larvae 

'»•( otiie <level()|>«»<l either into lie-maphnMiiteH having 

■fi«' ordinary stniiture, or into I h;i\« cailfii corn- 

.••nu'iital n>alt>s : and in the latft-r, 'he develMpinrrit 

JM-i a<^iiredly Keen retroirrmie ; for the male i» a mere 

-,nk', wliich !i\e« tor a •«hitrt time, and i- de^tituU' of 

iiioiith, stomach, or ollu-r ori,'an of imjxirtiin.e, exrept- 

niiz tor reproducti'Mi. 

^^ e are r«o minh aiTimtomed to <.•'« difTcreiu i-- in 
striKtiire hetween the eitihryo and the adult, and like- 
wi-P a rhce similarity in the emhrvos of widelv different 
aiimial« within the same class, that we mitrht Ih' led 
to l(n>k at the>« fart-s r.s nece-sarilv contini:ent in some 
manner on irroivth. lint there is no ohs loiis reason whv, 
for instaiire, the winir of a hat, or the tin of a porpoise, 
should not have heen tiketched out with all the |»art.s 
in proi)er proportion, an s(.on a^ any structure l>ecanie 
visihlo in the er.ihryo. And in «onie whole irroupn of 
animals and in certain niem}»er« of other croups, the 
emhryo doe«< not at any f>eriod differ widely from the 
adult : thuH ( )wen lias remarked in retrard to cuttie-fi>h, 
' tliere is no metamorphosis ; the cephalopodic character 
i.s manifested lonjr hefore the {>artn of the emhrvo are 
comfdeted;' and ajrain in spiders, 'there is nothirijf 
worthy to \ye called a metamoq)hosis.' The larv»e of 
inse<'ts, whether ad ipted to the most diver-e and active 
hahits, or (juite inactive, heint: fed t.y their pirents or 
pl.M-ed in the midst of proper nutriment, yet nearly all 
iKiss through a similar worm-like staiie of development ; 
hut in some few cases, as in that of A [this, if we l.xik to 
the admirahle drawinirs hy l'rofe>M)r Hu*iev of the 
de^elofiment of this insect, we «.ee no trace of the 
vermiform statre. 

How, then, can we explain the-e several facts in 

~' t'-!--et, — ;i3i!!ci; -.i.c -. c: V ;; t-:;t-: .1;, :;; : lilii- 

versal difference in structure f>etvveen the emlirvo and 
tlie a<lult; of partrt in the same mdividual eintiryo, 



- * -■ 

[i.i ■ 

which ultinifitely bec-orno very unlike and servo fo 
(luer-e purposes, heiritr at thin early peri(Ml of Krowtl 
.ihke ; — of emhryos of ditfereiit kjwtu^h witliiii the sam 
<l;iss, ^a-iKTiily, hut not uuiversaliy, rehemi.iiiitf eacl 
"Iher ; ^ ui l)ii» xtructuro of the enihryo not heinif cloMeli 
K'l.ited to Its i-oiiditioiiH of exiKteiic'e, except nhon th( 
•■rnl.ryo hcconie-* nt aiiv period of lite active and has t< 
provide for it.-eif . of the emhrvo apixarently haviut 
Hon.etinieM a hijfher ortranisatic.n than the' rnatiin 
■iiiitnal, uir., «-}iich it is developed ' I helieve that a] 
tiiese ficts he e^pl.ime.i. as follows, on iho view o 
dt'-ccnt with moditualiou. 

It is commonly assnin.-rl, perhaps from mon^trosilie- 
often atfectinj,' the embryos at a very early peruMi, 
thai slitrlit variaLi(»ns ne'-essari! v ap|»ear at an p<jiittll'. 
early period. Mut we have little evidence on tliis liead 
indeed th.- evidence rather points the other way; for 
It ii> not.), ious tliat breeders of cattle, horses, and various 
tancy ammals, ciiiniot po-itively tell, until some time 
after the animai lias been born, what its meritH or form 
will ultimately turn out We see this plainly in our 
own children ; we rannot always tell whether tlie child 
will be uU or short, or what'its precise features will 
he. The question is not, at what period of life any 
variation has been wiused, but at wh it period it is fully 
dw[)lay.'d. The cause may have acte<l, and I believe 
jfenerally ha.s acted, even before the embryo is formed; 
and the variati<,n may l»e due to the male and female 
sexual eiemeuts havint,' l)een afTected by the conditions 
to wluch either j.areut, or their ancestors, have been 
ex|)osod. Nevertheless an effect thus caused at a very 
early period, even before the formation of the embry*., 
may ap|>ear late in life; as when an hereditary ilisea'se' 
whicli apnairs in old ajje alone, has \>ecn communi- 
cated to the offsprinjr from the reproductive element of 
one parent. ( )r atrain, as when the horns of cross-bred 
cattle have been aflected by the shape of the horns of 
either parent For the welfare of a very youuir animal. 
:is lonj; a.s if remains in its mother's womb, or in the 
Btf>f, or as long as it Ls nourished and protected by its 



parent, it muHt \te unite unimportant whetlmr m()»t of 
iL« charat ti»r« are fully actjuircd a littlt? earlier or later 
HI life. it would not Hijfnify, for in^itance, to a Itird 
wiiich obtained its food best by having a lonjf Wak, 
wiietlier or nut it asf^umed a beak of tliis particular 
leii^tli, as loii;r as it v,:m fed by its |iarent>. Hence, 
I ronelude, that it is quite |>08.siblo tliat earh of the 
many Buccessne modirteations, by which tvich §pecien 
has acfjuired its jiresent structure, may have -^uiier- 
- eiieii at a not very early period of life ; ami some 
■ iirett evidence from our domestic animals Kupport.s 
thi-. view. liul in other rases it is rjuite possible tliat 
ca( li successive modification, or most of them, may 
i.avo appeared at an extremely early i»erind. 

I have sLate«l in the tint chapter, that there is soinc 
evidence to render it prohalile. tliat at whatever .-ure 
any variation first appears in the parent, it tends to 
re.ippear at a correspon<lin^ a^e in the otf^prinif. 
( erLain \ariations can only appear at i-orrespoM<lin:f 
aL'es, for insUince, peculiarities in the caterpillar, 
locoon, or ima^o states of the silk-motli ; or, ajfain. 
in the horns of almost full-grown cattle. Hut further 
t'laii this, variations which, for all that we can see, 
•iiitrht have appeared earlier or later ii life, tend to 
U'pear at a corresponding; a;re in the offspriiii: and 
parent, i am far from meaniriff that this is invariably 
the case ; and I could g-ive a good many cases of varia- 
tions (tikinsf the word in the largest seiise) which have 
sujKjrvened at an earlier ,i/e in the child than \n the 

liiese two principles, if their truth be admitted, will, 
I believe, explain all the above specifieil le.adiiiir fact- 
in embryoloyy. Hut first let us look at a few analoirous 
cases iu domestic varieties. Some autln. • wlio have 
written on Dogs, maintain fh:it the greyhounci and 
Hill-dog. though ajipearing so different', are really 
varieties most closely allied, and have probably de- 
scended from the same wjbj stock: hence I was euri.'i'jd 
'o see how far their puppies differed from each ..ther : 
1 >*a* told by liree^ler- that thev differed iusi as much 


ON IHK ()KI(;iN OK Sl'K(|KS 

n tlii»ir {».in-jit>, ;unl tliix. juilu^iiiL' I'v tli** ♦*>•»•, ».«'»-mcd 
iklniosl t<> Ik* thv caM- ; hut nn fwtii.illv riK'a-iiriiitf the 
old cli)i;<) and th<>ir six-davH olii |iiip|i:«*'', I fiuiiid that 
ihf {»u|>pn'«i had not iirarly ar(jiiire<i thtir full aiiuMiiit 
of j»ro[.Mrtiniial dirteri'iicc So, afaifi. I was tidd that 
th»> foals <»f cart aiid ra^»»-h<>^^«1J diri»ffil a* i>iij< li ;w 
tin' liill-irrow II animals ; at)d thi>* Hurpn-fd rii»* trrfatlv, 
a» I think it pmhaMe that thf ditftTt'iK-*' ht-'wei-ii tln*^^« 
\\<t hnM'dn has l>e«Mi wholly <aiiM»d hv s«d«»«ti<iri wndrr 
doiiK'vtirarion ; hut haviii-r had larefiil iii»M-iir»Mii»'iit.'< 
rnaitM of ?h« darn atid ot a thrp»»-da\- old <<dt of a raie 
and h«vivy rart-hor>-p, I find that t!i«' ciiits hav«» hy no 
Tii<;tii« a<"«|uirt'd their lull aiiuiunt of }iroj>ortiona! 

A^ the e\ idcritf appears to nie (•otirlii>i\ ♦•, thai the 
scv«>ral doint'stic- lir»'«vis ot l'ic»*on have di'Mienilcd from 
on»' wild >p»'<i»«s, I roinpart'd yoiiri;; pitfcons of vanoun 
hre«-.l>. within fw»dve hoiir- after U'intr hatrhed ; 1 
rarffnlly rntM^ured the proportion* (hut will not here 
tfue details) of the heak, width of ^lOllth, len^/th of 
no-,tril and of eyelid, si/e of feet and lenfrth of le^', in 
the wild stoek, in p<iuters. fantails, runts, harhs, 
dratrons, earners, atnl tuinhlers. N(tw some of ihe^e 
hird«, when mature, dirfer so extraonlinarilv in len;rth 
ami torn) of h«'ak. that they would, i cannot douht, l>e 
ranked in di>tinct tjenera, had they Ihh'ii natural pro- 
iluctions. Hut wlu'ii the nestlirnf hirds of the-^e -.exeral 
hrt-eds were placed in a row, thouji^h rno>t of them could 
he ilistiiitfui-hed from each other, yet their proporti«)nal 
difference- in the ahove speciiie<i noint.s were 
incoinpara'dv less than in the tull-tTown turds. Soiiie 
characteristic points of difference for insUiiice, that of 
the width of mouth- could hardly he ijetecfed in the 
yiMiiiir. liut there was one remarkalde exception to this 
fi.ic, for t'le youii4r of tlie short-faced tuinhler differed 
fri'iii the yountr of the wild rock-tiiireon and of tlie other 
hi»'»'(t-, in all its proportions, alnio-t exactly ;id much 
a> in the adult -tate 

j'l,^ UM. princ'ples ahove g-iven *e«-iu to me to e\|)l lin 
their.*- lact.s ni reirard to the later emhryoiiic stat;t^s o/ 





(lur <i<imp?»tn' vHriptifH. h 

aruirrH «u'l»Mt tin 


>*.'>•, arwl |M:r»'<»iH, tor hr.ediriif, «li».ii tliey iiri> 
• wn up; liifv arp imlrfcn'tit «liotlipr tJ.H <l«'%irtHl 

HT or 
IP lM.s«'S JU^t iriv«'ti, inoH" «'«I>«-<i;illy tint of 
"Mils, n»>i'iti to Hho:* tha* Ji 

• ji •liitio- .itid strm turn^ h;t\p U'rii a<-.|iiire«l •sirl . 
itiT wi liff, if tlip full-irniwii iiiiinKil |.o>,M*;s«'- tl 

\i>(\ tl 

e iliarartpr'ilir (lut»T 

H .•- whirii trivp v.iliip to Hjicli br»'<Nl, ami *ln. li h 

•"•"ii arciirnul.ittMl l)\ mat 

I H "eUM-tiiiii, have riot 


first apiipared at an early (K-rifwl of life, ainl 1 
ui(nTit»'(i liy the f>tf-i[>riiitr at a corrpvj.on,) 



fia> f 
'11' not 

irly ptTuxl. Hut the ca-r of tlie sliort-fac.'.i tiuiil.U'r. 
tiicli wlipri twplve hours old had a<-.juirp.i its pmopr 

itrtioiH, proves tlirit tliw is iif»t tli.> uiii 
t'rp the characteristic ditferei 

versa! rule 


icfs intist either hav 

'[•eared at an earlier period tliaii usual, or, if not 
e differences munt have been inherited, not at tl 




r.irrespondinjf, hut at an earlier a^e. 

Now let us apply thene facta and the ahove t... 
i.'-incipleH whiih latter, thoujrh not prove«l true, can 

-e nhown to he in some deifree proliahle -to si»e«ie»t 
lu a sfitt of nature. I^t us take a ifenuH of hirds, 
■i''s<etided on my theory from some one parent -species, 
.iii'i of which tlie several new sp«v,PH have t»e<-onio 
MH.ditied throuirh natural selection in accordance with 
tficir diverse hahitw. 'Ihca, irom the manv sliirht suc- 
cessive steps of variation havinjf supervened at a rather 
'ate Hire, and havuu; J^en inherited at a correspoudinif 
tire, the youiiu'- of the new species of our supposed 
L't-ius mil manifestly tend to resemble earh other 

iiucli more closely tlian do tli»> adults, just as we },ave 
"•en in the case of pitreons. \\\. „,ay extend tdis vm-w 
•■' vvhide families or even classes. I'lit. fore-lim».s, tor 
iifstaiice, whicJi s.-rved as Icifs in the {Kireii!-s|H.iiM, 
n iv tiave be«-ome, by a lonjf course of moditication, 
•da|(ted in omi diwendant to act as fiands, in another 
IS pid<lles, in another as w'\u^ ; .-.nd on the above two 
,i-Mi,i;.ies — nan.eiy of each successive modin.ation 
s .{K'rveniufT at a nther late ajje, and f)eint; iiih.Tited 
«t a rorrpsjioridinir late ayt- the fore- limbs m the 


ON rilK (»KM.IN (»K >I'K< IK> 

eiiiLrv"-.'! lli«- -Dv.' <leHreii<l;iiiU •)! tli.- |.;ir»'.if hi.-, i.-^ 
will Hliil ri'-ciniile oach <»lher cIom-Iv, t<>r liu'v a ill nn 
li.ivo h.'.'ii ni<Hliti«'(l. Hut ill .'ii. h ot uiir n.w ^|«.v 
111.- iMiii.ryoMu- fort' 1 1 nil.- "ill -litior irroallv from t)i. 
l.irf-litiilH ill tlH< nvitur«' innnal ; tlio limlis in \h> 
litter liaviii;.' n luliTtfoiif murli ni«nl,ti<:iti()ii Ht a ratlici*" i.«'riu,i o( lito, anil liaviiitf lli""' •'•'«'" ••oinertp. 
II, f(. lian.U. or i.a.j.lle^. or v^lnj:< Uliati-vt-r iiifiti 
eii,.. luiii.' .oiitiM^Ml ..uTriw. oi nsf on tlo' ori»' li.iti.i 
,uii. .liSiiM- on llie otli.T, may have in moriiiyinjf ai 
or::iri, influ.-n. »• will maiiilv aiioft tin- mattir. 
jiimnal. ^\irKli li.t- .•oiin« t4i it^ tull power-^ of a.tivif 
:iii<l lia> \n L'riMi lU own livin*; ; an.i 'he ori«v 's thu 
nro(iii."l will Ko inlxTitwl it a .•..rr«'-|.on(lin^ niatim 
aifi'. U iicr.'.i- thf yoiHi^ruiil rfma;ii iinmo(iiti<-.l, o 
Iw^ mo.iitii-.l 111 a le!^>er .Ir-rc.-, l.y the etfert^ ot" ur- 

an<l di-u-^*'. 

In i.Ttaiii ..lacs the Hucri'ssive steps of vanatioi 

miL'hl siiiKTveiio, from causes of wlmh we are wholl 

iuMi-.i-ant, at a very early period of life, or each ste 

miu'ht li<- inherited at an earlier period tlian that a 

which il lir^t appeared. In either ca«.f (km with th 

siiort-t.i. cd tunihl.'r)tlieyoiin;:<M <- ' -vovo;.; i closel 

rocnihl.' the mature parent-form. *> e have ««eeu th-i 

this is the rule of devel.ipment in certain whoie jfrouj 

ol" animals, as with cutlle-li^-h and spiders, and with 

M'w nicmtier^ of the ^reat class of insecUs, as with Apiii: 

With ropcct to the final cuise of the yountr in the.- not UMder;:oiinr an> iiietainorpho>.i-, or .losel 

rc-eiuldiiiir their parents from their earliest .iire, w 

can >ee that this would result from the two lollowin 

continirencics: firstlv, from the yountc, durin^r a coup 

,)f niodiii. atioii carried on for many generations, haviii 

to jinnidc for their own wants at a v»>ry earlv st;u 

,,f devi-lopment, and secondly, from tiieir follnwn 

cx.actly the same hahitw of life with their parent , ; f< 

III this ciM', it would he indispensal.le tor the cmsUmk 

of the >j.ccies, tiiat the ciiiid sikmiIu i*e ruMiilied at 

verv early aire in the s;une manner with its parents. 

accitrda.ue with their similar habit.>. >onie turtli 

■r''»H ■:-«... 



•III tnaUoii, bow.-v.T, of ho fmltryo not uii<)«'r(f-Mii|{ 
•iriv incUrnorpliOHii in pfThapx requi.sitH. Ij, on thi* 
ofli»T hand, it protih.! i},e ynuiuf to fo'h.w hahiw ..i 
li'e m any <l»vr»'» ih:t> n-iit from tho>ie ol thi'ir |k-(riMit 
ami constiijuenlly to ho ronstructrd in a ■.lijfhtlv dif- 
;<'r»«Mt manner, then, im tiic priiu-iplo of nl rit.iiur «• 
• orre-(KiMd ne •'^rex, the a<tivi> vonnj^ or l.irvw Tiiitriii 
M.'\]\ 1k» re'irirrctl i,y natural •i<'li»(tii>ii ditftTpnt to any 
' iinccivfihU' exU'n' from their p.«rftitK Sncli (iiiier- 
••mes ni .:.'hf, aUn, iK'.dme r<»rrei.»t«'d witli HH<Texsi\f> 
■itatres of liiiM'it.pmrnt ; ho tli« !.-irva>, in the tir'.i 
•<:.-iire, nti^flit diiffr crt-atly from 'liP hirv»' in the (i«>«'«>ii<i 
't,i::p, an we ha\«« -e«'n to Ih> tli« rawe witli .irripfdi-.s. 
Hie ailult miL'ht ht'Cdriie fif!»'d for sit«'H or hahiti, in 
wiiu h ortrans <i* hn oinndon or of th*- •i«>i.s»'8, wtc. , i»ould 
Ik3 usoIps- ; and in tliw easy llio final in»-iam«irph(»sH 
iMi'iid lie --.lid to lie n!trotrra<h>. 

.\ • all the ortranic hcui;:-, »'x*inrt and riri-nl, v»(i:, ,. 
iiave ever lived <tn this earth liave tn ItiTlansed tojfether, as al! have heen couue«'ted l>y the finest 4rr:i'iati<in>., 
■ lie best, or iudeed , if our collectioi'> viere nearlv [>erl»Tt, 
'he only po««ih]e arrainjement, w:>uld l>e >rein',iiotfi''ai. 
I>t>sfont heinp^ on my view tlie hidden l)ond of mn 
nection which natura!i^f.s liive he-" fekiitr vjnde: 
the term of the natural system. < )n tlnn view *■ 
•an understand Inm it is that, m tlie eyes of miw 
ii;»fiirali-tM, tlic htructure of the emhrvd is even mure 
iriipMrtanf for classifiration tlian tliai of the a^Jult. Fn,- 
'ii»- enihryo is tlie animal in itH letw modified Htate ; 
liifi in KO tar it reveal., the of itH |)n)::» tiiWir. 

II two t:iaups of animals, liowever much tiiey may at 

[■r.>-.ent d:if.'r from each oth«'r in structure and haints, i; 

hey pas.s ihroiu;}! thes.imeor similar emhrvnic stai,'■e.^, 

■vi- may tee! a-.-'ired they liave hnt'h .Icicendcii 

"in the same or nearly similar narciiLs, and are there- 
'"!e in that decree eli.».dy relattul Thus, community in 
eictiryonic structure re\ -als cnmmunitv of descent j- 
v»iil revcai this community ol de.seenl. imwever mud' 
'Jie struc'ure of the adult may have Ikhii m<Miifi««<j an.t 
■lii^cur^'i ; ■•*? havp -jeeii, for instarice, that '-irnpetie- 




ON !llh OKMrlN OF M'K("IK8 

ran at oiicp )n- rorniru\'*ed \>y their larva* as hfilfnu-ing 
t(» t]\(* {irr»-:i» rlass rif tTii>.t;ict'a:is. A-* X\io riiiKrviiic 
ttatf "If t'ii>'h sp^^fies aiitl (rroup uf •ipf'cies pftrtiaUy showH 
ijH tl.t" -triirture ot their h'v« moilit'u.'d am ieiit protrPni- 
'.ir-, MO cui clearlv few w hy aiu-icit ainl cxtirirt forms 
I* lift' 'ih'iiihl r«"-('nihk> f)ie enihryo- .>f tlicir '!»■- cnfl- 
4iit<. ..i.r pvi-tiiiif sp«'cif>**. Affassiz ht'lif \ <■■< tlii!* to 
*>♦> a l.ivv of nature; Imt I am hourifi tr) (•(int»'~r' that I 
iiiily )n»('e td -t'c th>> law h»'ror\f'ter proved true. It < an 
ltepr<i\e<! true iij lliii>e ca-ies ahme ;;» whicli t.'ie -iiuierit 
«tate. iH.-.^ supposed to he represented in em- 
lirvi'S. ii.iH not heen ohliterated, eitder hv tho suci-e^sive 
vari.afioMs in a hnitr (viur^e of rnodittcation havinir j'ijht- 
vpned at ;i v erv earlv a;c<". or hv the variations tiwintf 
>ieen in!ier;!e<i at an eariier rteri^wl than that a^ wtiieli 
:}ie\ Ur<\ appe.ired. It '-hould al-o t»e horm* in niitid, 
thai t}ie «i'jipo->ed I.t^ o( resenihlance of aji' ient forn»>< 
o.'' life to tiie enihrvonic ^tatres of rerent. forii:.-, mav he 
triM". hut yet, owin'7 to tlie ;r«»oiotci''ai re* ord not. ;^x- 
tendMii; tar enowtrh hark m time, inayrrinain tor;; !oi>? 
y^eriod . or for e\er, iii.-.ipahle of demonstration 

linis, as it seerns to me. tlie leadiritr tac't-^ in emhryo- 
io^'v, whi( h are second in importJince to none in natural 
lii^itorv. are .explained on the principle of slij^ht r-icvdifi- 
c.ttions not appeariinr. in the many de-cendants 'rorii 
-oiiie one ainMent ]iri>irenitnr. at a ve' early period in 
the lite of eaeh. fhoiiffh^ reused at tlie earliest, 
'iiid heiiiL' inherited at a eorrespondinc not early 
j)erio('.. Kfuhrvidoev ri-es greatly in interest, w hen we 
thu.>< look at the emhryo a*- a pn-ture. more or le.»s 
nii>('ured,<if tlie Common parent 'rm of each iireat cla^- 
of ;Hiiiii.i!s. 

h'lnh'Ut'nli. n, . ntrajihwrt ^ nr 'ifmrterl '/r./i/TjA. - « trtani 
or ]iar's in tir- •^trantre condition. he;irii u' the -t-imp of 
'nuulitv, ar(- ex'retuelv coinnion throu;i'liout n.iture. 

the m.iles of mainrnais : I presiinis» that the " tn'^tard- 
wintr " in hirdn may he >valelv cor ;ed as a iliifii in 

•> rudnneiiiiirv siat» in mtv uui .akfts oiiC toKe of 



the iMiijrs is rudimenuiry ; iu ottit>r siiakoM there art* 
riiii;'i!»'iits of th»- jM'lvi«i niiti hind lini^s. Sunif i»t t:ie 
(■a.-^e-- i»r riiiliiiHM'.Lirv dry:.'.!!-* art* exlrcint'ly ruriitut ; 
for iii^iantv, the jiroseiice o' tetith in Icftai w!i.iif.«, 
wiiiih w)i»«ii jjTrtwii uji li;iv^ not a tooth in their fuaiU ; 
at'.ii !h<' ('roeu'-f of t«»tMh, •♦inch iitnor out thrnii4rti 'i'e 
turns, in the iipjtfr jaws of our unhoru ralve«.. It ha.* 
oven l-Hcn sta'cd on ir'>o<l authority tiiat riidiiiuMit^ ot 
tpt'tli can l>i« <it'te<'fe<i u\ tlie iieaks of' certain emiiryonic 
ftird>. Nothiiiir can he plainer than that winj^n are 
foriiu'd for tli;:lit, vet in how many insprt.s i\i< we see 
wiuL'> ''O reduced in nhei a?^ to \n' utti-rly iiicapv.;.' iti 
riiirht, and tint rarely lyiufj under w mtr-oa.xe.-, nn.ily 
sohi.-red tOi.'ether I 

i'fie nieainntr <f rudimentary oryans is of>en .juite 
uiimi>tal'ahie : for iii'tance tliere are heetk-s at tiie 
•.aru»' treiius (and c^en of tlie same Hpecie^) resiMiihlin^r 
"acf! i)ti;er mo>t closely in all respects, oneof whirh *iil 
'la^e fiiii-!-:/id wiriij.s, and another mere riidimei'Ls or 
■nernlirane ; and here it is itiiposnilde to douht, t'.it the 
rudnnenLs represeni winifs. lludinieniary or^'ann some- 
times retain tlieir potentiality, and an- merely not 
developed : thiw seem>- to he the cane witli the mamm.t- 
of male mammals, for many instance^ are on rccdrd ot 
t)ie-e organs having' hecome well uevelope*! in full iirovvn 
males, having secreted milk. >o airaui t;n'r.« ;ire 
nurmally four develojted and two rudimentary teats m 
the uddiTs of the K*Mnis l»<m, hut in our diiine>iic c<''*>i 
the two sometime** U>come devtdope*! and tfi-e nnlk. 
In plants of the same .species the peials •.ometimes occur 
as mere rudiments, and sometimes ni a •♦jil-deveioped 
^tafe in plant.s with sep.irated >exe>, tiie mile tiovvcrs 
(dten h.we a rudiment of a pistil; ami Kdreuter found 
that t»v cro-sing su<'h male plant.s witli an herrnajdiro- 
dite sj„'( i(>H, the rtjiimont of the pislii in tli«' hvltrid 
otf>.prMiir wa.s much increased in f^i/.e ; and ti^i- »how« 
that thf rud iiHMit and the perfe«'t pi-til are er>scnti..i:% 



\i 1 Kf in I 

.;i.u 1 1 

-tara- i 

.\ii org 











•i>nie ru- 












d tor on 

% even 








niiiortaiit pur|M)>f ; and roiiiain perfettlv efficient for 

he nlher. Thus in plants, the office of the pi^'til \:i U> 

illow the pollen-tuhes to n-ach tlie ov.iles protecte-i in 

IK' '.■.arium at its hase. I'he pistil consists of a '^tiirma 

• iipiMrtcl on the style; hnt m some CftiTiposit.e, the 

iiale llori'tH, which of course cannot he fecuiuiated, liave 

:» pistil, v*lii,-h is ui a riniiinentary state, for it is not 

crowi.e.l witli a stigma , hiit tlie style remains well 

'Jevel'ipcd. and is rh.thed witli hairs as in (»ther (om- 

positB, (oi the l>, of hru.shina- the pollen out ofth.- 

■*urn)ii inline anther.-. Ajrain, an ort,'an niav hecoino 

riidimt'iitary for it.^ pmper purpose, and l>e used for a 

iistinct ohi.-ct : in certain tish the swiin-hladder seeir.s 

a l)e nearly rudirin-ntarv tor its proper function cf 

irisintf huoyanrv. hut has kn^oine converted into . 

na.scent Irealhni:; orpau or luujf. ( ►ther similar 

iintanccH could ho ffi\en. 

< )riran9, liowever little developed, if (it u-e, should not 
lie called rudimentary ; they cannot proj^rlv be '^liil 
:o he in an atrophied condition; they may he caile<l 
nascent, and may in-rt-atter he de\.'hiped to any extent 
hy natural selci-' <u. Kudiirienfiry nrirans, on tiie other 
fiand, are essentially useh'-s, as tet th ivhich never cut 
'hroutrh tlieirums; in a still less developed condition. 
they v^ouhi he of still ].->s use. Ttiey cannot, therefore,' 
under their jiresent condition, ha\e heeti formed bv 
natural -election, «!ii,h acts solely by the preservation 
or useful modifications; they lia\e iH'eti retained, as 
we shall see, hy inheritance, and relate to u former 
■00(1)1.011 of their |.o>sess..r. It i< difficult to know 
"hat are n;i.s< eiit organs ; l(M-k:ii^ to the future, we 
•uinot of cour-e teil how any p..fl will be dev.doped, 
and whether it is now iia>cei ; ; hHikinjr to tfie past! 
creatures with an iir;:an m a tia.sceut condition will 
uenerally have been supplanU"' and exterminated 
'ly their succe-ssors with the organ in a more perfect 
Hid .ieveloped condition. The win;r of the pentfum is. 
i iii^n servue, .»iid acts a> a iin ; it may, tiierefore, 
represent the na.scent stite of thp wiuirs of bi.-ds ; n..t 
that 1 helievt- ttuH to trt* :hf .Ave, it is more jirobahly u 



eiiiictvl o rtrau. riHMlifuM) tor n new futirtion ; the wintr 
.)f the Ajiteryx is useless, and is truly rntiunciitary. 
The mammary elain!'* of the ( >niithorhyiithus may, 
;erh.ips, l»«> (Muisiiiered, in romparisiin vvitli the urifler 
of a «ovv, as in a ria-<ent stAte I he ov !trer<ui« freiia 
rif certain cirrij>e<les, which are urily sl;ir)itly deveh)peii 
ami wliich have cea-e<i to ffixe attachment to tlie ova. 
ire nascent hrandna . 

Kuciimentary orirans in the individuals of tiie san.-- 
-[MM'ies are very liaMe to vary in deirree (»f development 
.ml in otlier re^^pects. Moreover, in closely allied 
fl pecies, the detfree to which the sinie ortran . as heen 

endered rudimentary occasionally differs nuicli. This 
,itter tact is well exemplit'i-d ui ;l:e state ut the win;.''s 
ct llie female motlis in certain jjroups Kiiiiin>entar\ 
■ Ttmus niay he utterly ahorted ; ami this imj.its, that 
•'e find in an animal i-.r plant no trace of ari oruan. 
ivhich anaJoiry woulil Ic.kI u^. to expect to find, and 
winch iM occasionally 'oiind in monstrous individual 
lit the species. Thus in the snapdrat'Dn (antirrhinum j 
we ireiier.'illy do not find a rudiment of a fifth stamerj ; 
i>ut this may soini'times lie seen. In traciiii: thi- liomo- 
if»i:tes of the same [>art ii ditlt-rent members of a class, 
iiothini: i" more common, or more necesscr\ , than the 
Use and discovery of rudiments, i'hi.s is well shf)wii in 
the drawin^is triven hy ( )wen ot the boues ot tlx' lej; of 
the horse, ox, and rhinoceros. 

It is an fact that rudimentary oriraiis.sio h 
I- teeth in tiie upper iavvs of wiiales and ruminants, 
can often be detected in the emriryo, hut afterwards 
wiiolly disajipear. It is also, I lielieve, a universji! 
rule, that a rudimentary part or <ir:ran is of jrreater 
-i/e relati'cly to the adjoiniriir p.vrts in tlie embryo, 
than ill the adult ; so that the (»ru';ui at tliis early a4?f 
■■•> less rudiineiit.iry, or even cannot in- >;iid to i>e in uuv 
iie;rree rutiimentary. Hence, also, a rudimentary orifan 
;ii the adult is often sa;d t«> have retained its emi>ryonii 

1 lia\e now given tiie leading fact* with res-^tect to 
rud!tiieritar\' (ircan.'i. In rt'fUi'tinjr on thi-m, eve'"v oMe 






mu<t >..■ -triirk wr.h -i-toni-iitn.'iit: fr)r;tip same reason- 
in- |M,w.T whicli t.'ll-. u- i.lainly n"-'t }'irt> u;d 
ortr:!;!- ar.. 0)i<|m-)t.'iv fi.l.ipf.-.i tor . titfiiii (.uijkis*-!. 
t»>ri< lis \M'li ••<|u:il ]i!inn:.'ss th;it \\\>'.-f rudinient.-irv oi 
atr..i,li:.'.l (uians, are imi-'-rfVot ;in<l ii-.-less. in w..rk» 
on lustcirv ru.liinfntary ortraiis are L'»Mit'nill> 
■^.li.l TO li re ii«'<'n 'cr.-ritecl " N.r tlie sak.' (it synnm>!ry. 
,.r ;ii ordiT " t.> c mi-h'to t)iP s.'licnu' of natiir.^ ' ; i-u 
this -.■fins to ni" iK» t'vpiaiiaT.ui, riieroly a rt'-stat.>iii.Mi 
of ili«' tH«-t. N\ o lUI 11 l>»* tlioiitrlit M.tti. i."!t to -a; 
tl it !.«'(a!i>t' |.laiit'ts r»'V(iUo in cUiv'k- •'oursfs roun- 
til.' sun. -atollites mllnw the siine .'ourse roiiml tt. 
plan.'t.s. tor the sake of symmetry, and to .•omplete th 
Kcli--!i:.> (if naMirer An eiiiinpiit physiol(.;:ist a.-rouir 
fur '.li»' i-rr-.-ii.t' of riKiinu'titary orLMiis. I»y Mijiposii- 
tha* tht'v s.Txe to exrrete matter in excess, or miurun; 
to the svst.Mo : hut can we that ti,e niinut 
pap. :ia. which often r.-|.re-ents the nistil in male tlower- 
and which is f(.riiie(i nierelv of celluhir ti-ue. .an th;i 
actr (an we siij-po-e that the formation ot rudimentar 
teeth. '.Nhich are stihsei|uent ly atisoriied, can he (it an 
service to the nipidlv trrowinir emhryonic calf hy th 
excreii.ui.d precious pho-pliate of lime .- W hen a man 
rinfirers Itave I.een amputated . imperfect nails somctinu 
appear on tlie stumps: 1 could as soon heheve that tlie- 
ve-tit:es of nails have appeared, not from unknown !,i.' 
of irrow^h. hut in order to excrete horny matter, as th; 
the rudimentary nails on the tin of the manai.-e -mm 
formed for this purpose. 

On my view of descent with moditication, the oriiri 
of riidiiiientarv ortrans is simple. We ha\e plenty of nidmientarv origans in our domestic produ 
tions. ;is tlie stump of a tail in tail!e-s breeds, tl 
vestijre of ill ear in earle-- l>reeds. the reappearan^ 
of minute daiurliiur lioriis in hornless hre.'.ls ot catti 
more e-peciallv. .accordiiuf to \ Ouatt. in youni: animal 
and thestjite of the wh<de flower in the cauliiiowc 
\\ i' oiten see rudimenl.s o! van.tu- jNirts ;n ::;!;::-;■.!•: 
Hut 1 (iouht whether any of tliese . ases throw lijfht < 
the oripn of rudimentary or^-ans in a state of nalur 



furtlKT than I'V ^^lMW•iIlL' that r'ulimPiits i;i:i (•«• {iro- 
ilijiffi ; ti'T I doubt wlu'llier sfift it'> unii.-r iiatiin" t'\»'r 

the main airencv ; that it Ins l»>«i in siicrt>*Ni\»> ci'iicra 


to ti 

»' t^railiial rcwiuitHm of various organs, ui.ti 

ive hfco'iit' rinliinei;t«irv,- .'«■* in iht* iM»t> n 

f ;i 

p\»'> ot aniinalH ; nliaoitiiic « 



and of tiif 


of" iiinls inhaliitiiiiT ocranif i>land-. wini'h ha\«' 
lidta t.oeii iorr»>d to take Hii:iit, and have ultiiiiatfly 
-t thp [.ovuT of tlyitiir. Atraiii, an orj: an iis»«fiil 


tTt.iiii conditiniiSjmitJrht Ix'coriic injurioiisiinderothfi". 
a-- V* ii!i ;!n- « nitrs (if iKjft .(•> li\in:r"n ^niall arni i'xpoM»d 
i»I:ii;<l-. ; athI II thi-* ''a-t* natural fwlcrtinn '^ouid coii 
tmuf viuHlv to r«'<iiii-e the urtfau, until it was rriid»'red 

ariiiiess and rudiniv-utarv 


lariirtJ in functitiii, 

liiirh ran he etffc'ed bv 

;n-L'ii<irily Mnall >l«*|»s, is wi'hin the power of natural 
-oil'. -t ion ; so that an ortfan rf-ndercd, 'ii.rnii.' lii.nuftvi 
• ia''!"- of life, u-ele^!* or iniurious for one purpoe, 
uiiiilr he nioilitictl and uvd lor anotner purp< ^e. 
'r i:; ortran nii^ht he retained for one alone of it,-* 
toriiifr functions. An oriran, when ri-iidered u^ejr ^- 
mav well he vanahle, tor it* vanatiMus lannot in' 
che. ked bv fiatural sele'tutn At «liatever perani of 
lite d:>use or <elei:tion reduce-, an ori:an. and this will 
iit'iierallv Ik* «}ien the lieiuir ha> corne to niaturitv an'l 
to it* full powers of aftion, liie prinripie of iiihei.'an<e 

•it ( orrespondintr aires 




e ort^an ui 

dmed gtiite at the same aAr»*. and < onsetiuenti v will 

^eld.iiii atTect or redu<"e it ii 



1 hun 

we can 

understand the tjreater relative ni^e of rudirnent.iry 
or;:-;*!!* in the einhrvt), and tlieir lesser relative «-i/e in 
tlie idull. Itut if each step of the pro. ess of redui iion 
Hereto *>e inlierited, not at the correspondiiii: ai.e, hm 
H' an extreineiv early period of life («s me have tood 
rea-nii ro believe to 1h' {wissihlci, 'lie rudimentary pari 
.voulii tend to he wliollv lost, and we should hhve a ca.«e 

I i. 

• t.i< 

^n i^t <Ai*( iri< irr^ 1' 

exj'lamed in a former cha[>ter, liy v^hich the materialu 
rornnug anv part or strmture, if no; u-etul to Uie 



(»N I UK oiSKilN (1^ M'E( IK- 

[„,sk(.,,or, w^ill ho (<av('<l a- far as is i>o«sih!o. vrjl 
DiMhahly ottf'ii COM!*' into play; and tfiin will U-m 
i<> faii-;p tlie entire ofiliti'ra'ii ii of a nuiinientar' 

As the pr<";t'ncp of nidirruMitarv nri^aus' is tliii 
(in* til the tiMiilency in «'vprv part of the nrtranis^ition 
«li:ch hart l»)n^ existrd, to he infierited »>• can under 
stand, on the eenpalotriral vjewo; cla«sihcation. how it i 
tliaf «\ stiMr)ati«-t- liave found rudimentarv parts as u^efu 
as. or even Horo'-tiniea mere useful than. ,»artj« of hiff) 
phyi-i jlotrical importance. Kiidiriifntarv orirari^ mav t.t 
«-oinnared uith the letters ui a word, still retained ii 
itie spelliriir, l"it he<-iiine useless in tlie pronunciation 
l>ut whicli ser\e as a clue U' seekirii.' tor its derivation 
< hi the view <)f descent with modification, we may ton 
cliide that the existence of ori:ans in a rudimentary 
imperfect, and useles.s condition, or (juite ahnrted, fai 
fraui presentmtr ;• str.iuijo dithculty, as thev ,issuredl\ 
do on the ordinary doctrine of creation, imtrlit ever 
have heen anticipaicd, and can he ac<-ounted for hy th« 
laws of iulicritance. 

Suminnry. -In thi> chapter 1 have attempted to.stiow, 
;hat th*».suhordi nation of trroup totrroupin all orjraniswif 
throua:hont al' time; that the nature of the relationslnp, 
liy vvhii ;, ail livintf and extinct heimrs are united hy 
lomplev. nidiatinj;, and circuitous lines of arfinities inti 
one ffraiid system ; the rules fnlhiwed and the difficulties 
encountered hy naturalists in 'loir cla.s>ihcations ; thi 
value set upon charaiters, if constant ami prevalent, 
whether ofliicfi vital importance, or of the rmtst triflint; 
importance, or, as in rudimentary organs, ot no import- 
ance ; the Wide opposition in value hetweeu anaioirical 
or adaptive characters, and cliaracters of true atfinitv ; 
and other -Mich rules ; all naturally fullow on the \ie',? 
of tlie common jKirentatre of f«»rms which are 
ct(n>-;dered hy naturalists as allied, to^^elher with tlieir 
mddiiuaiinn tiiriiu;:ii natural selection, with it-s con- 
tingencies of ertmction and diverjrence of char.octer. 
hi considering M i- view of cLi>-.-!:'.(alion, it Bhouhl h*' 



irno ill niinil that the olemeiit of deooent haa i>eeri 

jiiivtrsaily usfil in rankiinr totjethor the m'XPf, atce;*. 

i:;ri aoknow!c(lii:«;d varieties of the sanir r.pftie-«, liowfvpr 

:i.*^ercnt they niay he in structiire. If we extent! 

:he line of this element of descent, — the only certainly 

; .lowii taii-e of similarity in ortfanic U'iiitiH, — we shall 

•: ■tf'rstaiid what is meant hy the natural system : 

• ;- penealofjiral in iti attempted arrangement, with 

1 irrade'^ of ac(iuire<l dit^ereme marked hy the 

. '^mM \,trielies, species, t^etiera, famIlie^, <irder^, and 


On thin -ariie view of descent with rnodifi'-ation, ali 

he ;;reat fat-t>* in Morphoio^'y become intelliyilile, 

h» we look to the same pattern displayed in t!ie 

i.uniiil'urous ors^aiiH, to whatever purpose apjdie«l,of the 

l.tferent species of a clasg ; or to the homohiirous parts 

Mnstru(;te<l on the -..ime pattern in eai h ;ridiv ; 

t.'iimal and plant 

< >u the principle of succes>i\e slight variations, not 

ccessarily or generally .■«uperveuing at a very e.irly 

. iTiod .>f life, and W'intr inherited at a rorr»-spondunf 

;..'rii>(i, we can iinder-<t;ind t!ie great leadin^r factjji in 

i-in »ryolui.'y ; namely, the r^>^enlhiaIu•e m; .m ind- 

• ntu:tl enit>ryo of the homologous part.s, which v^hen 
f;a»'ired will hectiiui widelv differe'it from each othrr 

;i -fructure and function ; and the resemblance in 
'irferent species of a of the honiolot;ous j>art« or 
iT^rans, though fitted in the adult n •.• ibern for pur- 
(inses as different ;i- pos«iili!e. I«arvi^ are active ein- 
'ryos, which have Itecome specially modjtied in relation 
■• their habiu* of life, throii::h the principle of niodihci- 

(>!.- being inherited at r..rie«ponding ages. On thi^ 
^.iiiie pnncijde— and liearui^ ii< mind, 'hat when organs 
I'e redu< fd in si/e, eitlier trorti di»:,-c or seli-ctu'ii, it 
v.ii t'enerally t>e at that period of lite when the hen:;; 
f i^ to provide for its own wants, .Uiii tie^iring in mn 'i 
:i"'>v siroug Is the principle of inlientance- the «)ccur- 
■•■iice ijf ruUimeiiUiry organs .ti.ii liieit liuai ai»orlion, 

e-ieit to us no inerplicabl,- tl,rficuitien ; on the cou- 

• 'rv, their preM;nc« mi,'<ht tia-e i>»^n -v^eti autic!i>ate i 




Iho iriii'ortArice of pinbryolojjical charartfru atMi o 
rudimentary ortraiiH in rl.isHiticatioii in iiiti'UnriMe. u 
the \ le** that an arranjfemerit is only so tar natural r 
it ih p»'nwii(ii,rii'al. 

KuihIIv, the «evf!r:»l rlasses of facts whicii liave Uh»i 
coiHiiiereri in linn iliaptvr, Mvrti to mh- to |tr<Hlaim •<( 
plainly, 'liat the inniiineralile wjiPcii's, jrj'uera, am 
fannlf's of orp^inic hoin/s, Aith v\|iirh thin world i 
pe<»[>l»Mi, ha\»' .ill d«'j»r«*nde<i, emch within it-x own das 
or group, from romrnfm panMitj*. and have all be«"i 
mod H»*d in thp rour**' of d«\-( ent, that I should witliou 
hft.xit.rit «in a/iopi fhih vi»'w. *",cn if it were uiisiip[>ort«^ 
by other faobs or arj^-uinentH. 

M 4 T ? 

SB? 'V-. tM 



(HAITKH \i\ 

H^• API I I I.ATll'^ AMI I (>N< I I fc|t>> 

K' \r> <if tl.e 'i'TIi ultlei i.n l!.'- theory cf Sa:ur»l yr'"^-t.cii 
!L( ■•jiltiiUti 'ii (.f U;r (fiTirra! ir •' ijwi iaI l•l^■'llll^^«^■■l-» in ttj 
t.ivi>ur I'Hiifrt (,f ifie k-ftJ«T»l I" in-f in the iiiin..ii»lnlii.y u( 
»i><i i<-» H"4» far iiif tjir.ry '.f imtur*! •rl.-iiinti n%\ tx- ex 
t«i) !••■] KrTfi-U rif iu fc.l')pti'>i. in Ui< ilU'ly i.f nutiir.! ' «♦. ry 
C'oiK-luilInK rt-nikrki. 

A" this whule volume !•< one loii^ arnunu'iit, it fp;iy b« 
coiivonieiit to the reader to ha\e the leadiiijir fartj« Hiui 
interencw hrieriy recapitulated. 

1 hat many and werioue ohjertions may Jk* .'idvanced 
airniiist the theory of de«<eiit with inodifitalion throuirh 
natural selfi-tion, I do not deny. i liave endeavoured 
t<i trive to them their full force. .Vothiitjf at fir«t i-an 
qipear more difficult to believe than that tlie more 
loinjdex or^aiio and instincts s^iould have J)efn [H'T- 
tVctwi, not by meai ij>erior to, thou(;h analotj<>u>. with, 
h'.riian reawon, but liv the accumulation of innumer- 
itde sliffht variations, each (rood for the iiidivxlual 
]„,«,HSf*or. .Neverthelesx. tl.i.s difficulty, though ap- 
["•irinji; to our imatrination insuwrabiv jfreal, <annot 
|>«' 'onsidered real if we a^lmit the foll(>wintf propoHi- 
tions, namely, — that ^rradations in the perfectinn of 
^iiV urtfau or instinct which we may consider, either do 
now exist or could have existed, each iro<)d «it its kind, 

that all ortraiis and instincts are, in ever so hliifht a 
,l..rrv«. v»riahl»>, — and, lasilv, that there is a >trii:rt?b- 
f"' -existence leadiujr to the prewrvatiou of eadi profit- 
;«f le deviaL'i»n of .structure or instinct. The truth of 
t'lt'M- propo^iUoni cannot. I tliink. 1* disputed 



ON MIK ()IU<;IN «>K .s|»K("IKS 


ll 1.-. an <iiiiilit, e\Lrem«'ly <iitru'nlL p\f'ii t<» rcir*»ot i- 

}<y wlint {jrad.itinriH many R^nut iin-s li.m- ln-cii [•«• 

UiitT'l, more I'spoi ;,il|y ^tiio.i^rwt hiokc"! tinl faiiii: 

irroiij>s fif ortT.iiiii' Immiiit-* ', l»iit wf vcc ^n many "^traiit 

trr;i«Utiuiis ill iinf.ire, wc du^'lit to bo t-xtrcmf] 

,1 i'io .' in 'viyiii^r tli'^f any rtri^aii or in~tiii. ♦, or ati 

vlmli' liririi,', rnulii not Im.m arrived at it« pr<»'-oi 

•ato hv iDiiiiy Lcri'liiatod Ktt'j>«. 'liuTf .i'". it mu 

'!<• a'imit'<'(!, ra-«t» 'tf sjjccial ililliculty otj the tlicor;." ( 

natural M-lortiou ; and oiip of tin- mf>»t curioiK of tli.v 

1- tliH cit;-tpiic«' of two or thror di'iirioii ca-tc-. of .*orkp 

or «teri!»' fp'nalo« in \\ii' >imo rommiitiity of ants ; In 

1 liavc attt'rnj>t«'<l to >liow how tliis dilJuMiltv lan \ 


^\ itli rosjiect !o llie almost uiii\»'rsal sterility ' 
•,.!>, ies wluMi fir-t crossed, vvliich forms so rcmarkal) 
I contract with the almost tiiiivcrsal fertility of >.ariotii 
when crossed, i must rj-for the rcnirr to the recapitiil 
tion of the lactM trivon at the end of th»' eiL'^hlh ihapto 
which -e«'m tt> me cnncliisi\plv to show that tliis sterili' 
!■- no mure a sjMvial end(>wm"iit than Ih the incajiacil 
■ )f two tppHs t/) he grafted toirether ; hut tliat it is inc 
dental on constitutional ditferencP"' in the reproducti' 
-ystems of tlie intercros-ed spec ie> We see the trul 
of this conclusion in the vast d'lierence in tlu> resul 
vheu tlie same two species are crossed recipro'ali\ 
that is, when one species is tirst used as t)ie iier at 
then as the motlier. 

Hie fertility of variot 
tlieir nioriirrel ntT-;prinf; 

versal ; nor i.s their very ^•eiieral fertilit\ ^nrprisii 
when we rememher that it is not likely that eitli 
their constitutions or their reproductive systems phow 
liave been profoumlly modified. Moreover, most of tl 
arietir- wiiich have been e\])erimetitised on liave l>e» 

Hie fertility of variotio-^ when intercrossed and 
-prinjr c^aiuiot he cunsideri'd as ur 


jiider domestication ; and as doniestLatif 

'I do not nie^an mere confinement) apparentlv tends 
iiminate stciility, we outflit not to e\|»ect it also 
[iroduce sterility 

The stenlitv of hvhrids i a very ditfcrent ra^o 'rd 

Hr;( AlMIl LAFIHN aM) ( ()\( l.f'SK tv il.s 

.•.Id/ nr«t crns^cM, for tiieir ri'pn'ilurtive <ir._'i'i-. ii'>- 
-nd'p or less tiinctionilh im|t<.«i'iit ; »lu'n'.i.«» m hr-i' 
■r'-ses tli»' KPt; iii> oi: iiotli xnlp*; are in a |K"-'>-t mn 
litioii. As w«> coiitinii.illy sfo oriraiii-iii- of al. 
-iiifin an* rcMi'lfri'il iii •"iTriP (U'lrrc** -tfriU* fnuii iIh- r 
. mi-'titiit.ons having hcpii distu: •••d by sKf'itlv fl;rff 
fiit aiiH lu'w ciiiiditions of lite, «<• in'i'il imt u'ri 
- irpr -' at, liv!iri<ls K»'iiii.' in koiim' dt'^'^rff ■iN-riU', for 
• 1 ..!i-.titiitioiis c-aii tiinlly f.i'l to liiv.- 'i.wmi <1m 
urlK'ii from l»«'iiiL' roinpoiiiulf*! "t twi <li-t.iiirt or- 
.'aiii^atioiH. 'I'lii- paralleli-m is sn|i;.(.rt»Ml by anolluT 
•■I'.ili.'I, hut dircttly o|>i.oMte. rl-i-s of fact- ; iiaiTU-iy, 
t.ii tht' viiToiir and fiTtilily of -ill nri,',iiiii- l)»-iiiir»* ar»' 
■,-Tt'a-t'>l i'V -IiL'lit fliatigj's III 'ln'ir i-oiniit.oii'* ot li:.-. 
i:id that tlie otfsnriiiif of sliir^tly inodilii'd forms or 
varieties acquire from heiiitr (TO-himI increased vijjour 
iini fertility. So tli.'it, on tlte one liaiid, cousiderali!.' 
■li.iiijre-i in the (umlit.ons of life and i-rosses l>el»i'ci. 
,'nMtlv modified forms, lessen fertility ; and on the 

ther liand, lessor rhanires in the conditions of lite 

id crosse.-) between less modified forms, 

I'lirnin^ to (.^'oirrapliical (i!>tritiution, i he dilTicuIli''- 
. ,. oiiutered on the theory of descenl with modificalinn 
ire tfrave eimnjrh. AH the iiidividual.s of the mime 

[H'cies, and all the upecies of the s.ime j.'enii'i, or even 
li^'^lu'r jrruiiji, must have descemied from common 
;>ar'-iUs ; and therefore, in however < and isolated 
;).irt,s of the world they are now found, ihey must iu llie 
•iHirse of successive geiier.itioMs have passeil from some 
UK- part to the others. We are often whollv unahle 
.'."•!i to conecture how this could h.i\ e Keeti effected. 
N el, as we iia\e re^i-stMi to believe tt' it -nine «pecies 
' :»ve ntaried the s,ame sj«»(ific forin lor very inna 
:>eriods, enormously Ion? as mea-ured by years, too 

'luch stress outrht nui to be laid on the occasional wkIp 
;itfusi(in of the same species; for durintr ver> loin; 
iieriods of time tiiere wiii always iave iieen a ^ood 

ii-mce f 'P Wide migration by many iiseaiis. A hrokei- 
'<r 'liter: ir.'*ed raiiire may often he arcouri'ed for b\ 


ON NIK « •KI(;iN « »F >^|'K< I K.s 

iric extiiirtiiiu <»! tin" »|.<>i ,,- in tlio itibTim- 
rHtr;<»ii>. It r.iti'i'i! In' (ii'iiii-il tii.iT Hf arf a-i \»*t vtTi of ttu* full o\'»'iil of tlif *.irniii«i .•ni 
.re«ii.'r:i[ rlirit!i.M— whuh K.ikr af'crted t>i»' f.irtl 
d'lntiir tiKxItrii i>tri(Ml- ; anti "i':' h « i!,'iti;rt» nili nli 
viounU have tjrf.itiv t'at'ilit.itfl tiiiirratiun A" ai 
••\.»n, jiU'. I ha.»> rtUfriiiiffil to '•hou liovv potoiit liai 
ii<'»'li 'li" 'lifi iM'lir*' mT tlit> ( |>iTit>(i nil tli»' >{\y 
triliul.nn 'H)tli (if tliH ».i!ii>' iiid ot rt'[irr»»'iit;4tiv( 
>j»«'i "■■) throiitrli''iit iIm* vvond U h an' ».•< v»»» pro 
tdiiiiillv i^riioraiit ot th»' iiiaiiy oira^innal u!*'.!!!" o 
trans'port. N\ ilh rp-i>t»ct to (iistiiii't -.|ni-i««.. of ttn* --itrK 
^piiu- mil lint lU'f \t'r\' liistant and i-oii'cd r»'i'iiiri«, i' 
tiif pro. »•-■. .ir mn.iifiratiKii (i:i- n**" i'-.-^iri! v Ih»m. »1i)W 
a!i till- • .I'.Kix lit inmratMiii will it,i\n U»«mi po-"<ild( 
d .mil,' ,1 \»Ty li'ii;.' ['(tiimI ; and < oii>-»'i|'it'fitlv tli« 
■ 1 till uit\ of the wide dirfuKiuii of sjM'cic-. of lli»> - uni 
-eiiux iH III -uriu' d<'irr<'«' lt'>><'!i»»d 

A- on the t h»*ory of' iiaturi! -i-lt'ction in iritcrnunaidi 
iiiini'wr of int^Mrnodiate forms n\\i>l liavt' exivt*'!! , lirikiiij 
totTBttier all the »pp<i''s in eai-h uroup hy lotis a; 
tino as our prost'iit vari»'t!P>*, if niav )••• i^Hi'd, Why d( 
w»> not -t'p tht'-^e linking; forms all aroiiml im " Win 
are not aii orjfanir in'inyN hU-nded tOiT'-ther in an iiifx 
tri«'a('le ••liao-« r NV'ith rp»[M*.t ^o pxistnij; tor:)-. w( 
should rpin»'Tn!>pr that we h.f i< no riyht '<i cxpec 
ipx'<'[>tinj{ in rare casps) to (iisC(i\or dtrfi-th; coiineclinj 
links l)et\v«'»'ii ilu'in, hut onl\ hetween ea'.h and >oirn 
»'\tiinM and supplanted form. KNen ou a w df area 
whiidi h.t-; duririif a Ion:: ponod rt'mained contniuous 
and of which the climate :uid other i onditions of jifi 
ctianije iiisensihlv m coin^ from a district occupied l>i 
one spfcios into iimther (Ji^trict occupicii hv a cln-.fli 
ailii'd species, we have no iu«t riuht to exj>e4-t often t< 
find inlermedi.ite varieties in toe in'ermediat* /one 
V^^r we h.ivo re-a-oi, to helieve tiiat ouiv a few -pecic 
are underLM)inir chantrP .if .'iriy «»ne period ; .ii.d a! 
ciiatu'fs are sioviJv eftrcteii. 1 have also »fi((wn th.'i 
tii>' nitcnnediafe varieties which "ill at first orotiald] 
exist III the intermediate ^ones. will l>e liahie to b< 

Kh( Arm l^llON AM) ((>N( U MON U7 

■ •;i|il.iiil»«l li> tilt' allif«l furtii-i mm ••iflier haiiil ; anti tlie 

. .'^ivr, troiii I'vi^titiif ill trriMii-r iiiiihIxt^, will ct'in'railN 

■■*i tiKMlitii'tl anil itupruvitj at a (jun k»T rate tliaii tlii 

;;t'Tiiifi|i.itr varictirs, uliicli rxi-t in l«'-,-fr iiuTiil.t>r« ; 

■ tin- intt-riiu'iliatc v.iru-tn-^ v*,ll, it; i}i»« lonir run. 

• -liiiplaiit*"'! ami ••xtermiiiati'il. 

« »;. lluM ilot tr.iif «)l tluM'xtrriiiiiiatioii .,f ,in iiiiin.tuii.- 

.if •■n:iii(.,-tintj links, Ki-lwri'ii the livin;; and ••xtin. t in- 

li' l.iiiLv i)t tl f World, and at ••acli Mj.««'v>.i\t> (xthhI 

t'>vfcn tlif extinct and htiil <ild.T !»ii«'.ic!4, win i-. ni'- 

• iry Cfid. laical lormation i liaPLM-il with «ii» li link- 
liy dm, nut e\ery ioll«Tiii.M (»t fn^sil retiiains alldid 

^i.ii i-Mdiiire of the irradatJMn and iiinUfiini i>f the 
- iii> or li;.'.' ^\'e tneel VMth no sn. h evidi-nit', and 

M« i* tin' iii(i--t (divinus and turcilde of the man. 
• 't fHin- whiih may l« ur^'cd at'ainst my tlu'tir) 
^ ly. a-am, do whole tfroup!* of allied t*|W'.ieH appiMr, 

•..'HiL'li fcrlainiy ♦'.••y often fal-ely ajipcar, to h;i\e .oii.e 
I M'ldd.'nly on the heveral t;'''>ln^-icai sUt-es r \\ \,v d«. 
'■ init imd trreal piles of straUi l»eiu'ath tiie >iliirian 

- -tciii, vi.ued with the remains of the proL'enitijr.s 

• li:e >ilunaii groups of fosMls.- For ceM.nnly on 
: :i\ theory Mirli Htrata must somewhere ha\e heen 
we|H.N;ted at these aniient and utterly uiiknoHu epueli- 

•1 the World s history. 
I can answer tlu-^e <juestions and ura^e ohjcetion.-. 

• ' i!y <in tiie hupposition that the ^eoloj.Mial record is far 

• lie onperfc. I than ^e<docistfi helie\e. it cannot 
•' olijecled that there hajt not l>een time sutheieiit for 

' ly amount ot ortrani<- charitre : for the lajiM) of time 

L- heen so :;reat as to he utterly inappreciahle hv the 

itiian intellect. J he numU-r of hjKjeimen^ in all our 

."j^einns is ahsolutely a.s nothing comjured with the 

■ "uiitless generations of vountle^H specie^ vvhjcli eer- 

t.iiiily ha\e existed. We should not l»e aide to 

ui ..^Mii.-.e a HiKJcies a-s the parent of any one or 

'i'*'tie«4 if we were to examine them ever .so cloM.dv, 

linh'-i^i ivi- Hkewice t..v--e^-e.! -.-.-.-.-.■ ..f -.'.... :..t, ;;„! 

i.nks lH''we»'n their j»;».st or parent and pre.sent states ; 
••'■id t!ie>e many link:* we couUl hardly ever exi»ect to 





(iisrover, owiiiif Ld lh<' iiripertVctioii of thti jr'M^'ojfical 
rei'inl. NuiiirroiH exi^tiii;.' duuldml fornn ••ould be 
uwikmI which ;ire prohahly variotios ; hut who will pre- 
t«-ii<i that III future airi*s so tn..riy fossil links will \)e 
discitvpred, tliat nHlar;ll^•^t.s will he ahle to <le< id**, on 
till! (0111111011 view, whether or not tliese dinihttul rormn 
are variftien .' As Ioiil'' hx most of the links hetHt'»;u 
anv two species am unknown, if any one link or inter- 
mediate variety he discovered, it will simi'ly he classed 
as another and di->'.inct sp»>,icfl. ( )iily a -iiiall portion 
of the world has heeu ^eHl((;:;cally explo.-ed. Only 
orLMiiic heintrs of certain clar« can he preserved in a 
fossil condition, at lea-st in any irreat numher. Widely 
rui^anu: sjH«cies vary nio«t, and varieties are often at 
first Incal, — both causps* renderintr the discovery o1 
intermediate linkn less likely. bn-al vaneues will nol 
spread into other and dis.^int retr'oiis until they are con 
siderahly modified and improved ; and when they dc 
spread, if discovered in a tjeolo«ical formation, thej 
will appear as if suddenly created there, and will b« 
pimply chi-ssed as new species. Most formations hav( 
been intermittent in their ac-cumulation ; and theii 
duration, i am inclined to believe, ha.s been shortei 
than the avenuTP duration of specific forms. Succes,siv« 
fi.rmations are separated from ea-h other by enormoui 
blank intervals of time; for fossiliferous formations 
thick enou;ih to resist future det'radation, can \h 
accumulated only where much sediment is deposited oi 
the subsidintf l>ed of tlie sea. Durintr the alternat4 
periods of elevation and of sUitionary level t)ie recori 
will l»e blank. Duriiiir these latter jMiriods there wil 
l»rohably be more variability in the forms of life ; durinj 
j)eriods of subsidence, more extindioii. 

With rer-pect to the absence of fossiliferous forma 
lions beiie.ith the lowest Silurian strata, I can onl; 
recur t.i the hypothesis tfiven in the ninth chapter 
Til it the jfeolo;ri,-;il record is irn|terfect all will admit 
but liial il i:' inipt-rfert to the dcirnu whli h ! require 
few Will be incluievl to admit If we look to lonj 
enonirh intervals of time, j^eoioj^ plainly declareu tha 


, *'» 


tM •^^•'i-ies havB c-haiit:t'il ; and thpy havo ciiainr,..! m 
•h" miiiner w'nich rny tlicory reijiiin-*, for tJwy i.ave 
ch.iiitfe'l slowly ami in h trr:i.liiat*»«l maimer. W »• 
.•!»*ariy M-e this in the tnssil remains fritm con-eriitiv 
*'nrmati«)ns invariably l>eiii;f niiiili ninrt* clovi Iv ri-\,\'f>\ 

■ ♦Mth other, than are tlie f<)s.sils from fcrjiia'.i'i'is liis- 
•..;i' frnm ea.'h ntliPir in time. 

.">Ufh 1^ tlie mini of tlie several chief ohie«t;i(ii-i and 

i:fh<-iiiiies which miy justly l»e iiru»'<l a.i:aiii-l niv 

iieory ; and 1 lia\e now hnefly recajntiiiated tlie 
.ui-rters and eii<ianati(tiH wliieh .an be tri^en to 
Ihem. I hav.. (V-Jt these dith.ultieH far 1»mi h.-avily 
durin? many years t<» doiiltt tlieir weij/ht. Hut it de'- 
-<Tves e-pecial notice that the more iniportunt o!)).'c- 
t (ius relate to (juestionw ou which we are (•onfe*v,.,ilv 
is.'norant ; nor do we know how itrnorant we are U'f 
''.>i not know all the |.o>*ihle t.-ansitional gradations 
l.ttween tlie simplest and the most '.erfect orirant ; it 
I iiiiiot he pretended that we know all the varie<i means 
ot i>i>lrihutioii durinfr the lon^ laps*, of vears. or that 
we know how imjwrfeet the (Jeoloyiial Record is. 
• .rave as these several dirticultips are, in my jmi^rment 
they do not overthrow the theory of descent' from a i.-w 
credited forms with suhsequent moditicatitin. 



N(.w let us turn to the other side of the arjfument. 
i iider drmiesticatiou we see much variahility 'Iliis 
•ieeiii- to he jnainly due to the reproductive system 
heint;' emiiietitly suseeptihle to chan>fes in the condi- 
tions of life ; so that this system, wlien not rendered 
impotent, fails to reiiroduce offspririj; exa<-tlv like the 
partrit-form. \ariahility is ifoverned hy many compler 
iaxvs, - l,y correlation of trrowth.hy use and disu-e, and 
l»y the direct action of the p}iys;cal condition?, of life. 
I here is much diffieulty in a.-^rertaining how rnuch 
:iiodificat;on our domestic productions have iiniier;roiie; 
i.ut we tnav safely infer that the amount has Iwen 
"iTpre, aau tnat iiimlihtrrtliuns can i>e infieriu-d (or ioiijf 
jteriod-i. As loiitj as the conditions of life remain tlie 
-ame, we iiave reason to l>elieve that a m(»difi.atio:j 

.-t,^ , 

"^ir il: ;■ 



which has alrt-afiy hcou iiiliLTitod for many treiioratioFH 
nmy roiilinup t<» 1»»> inherited for an almost intiiiit* 
iiutn?«>T of ^'^•MH>ration>4. On the otiier l)u;ui we iiav( 
evidetu'p tliat varialulity, when it h.m onco come iiiU 
play, liopx not wliolly coa-c ; for now varieties are stil 
occosiiinally jiroduced hy oiir ni(i>t aniieiitlv domesti 
I'ated |ir(Mlijcll<ins. 

Man (iocs not aitually .rodu'-e variahilitv ; ho oiih 
iiiiintontionally exposes oriranic l»oiii{rs to new condi 
tions *)f life, and then rature acts on the ori:anisation causes \aria!iility. liut man c^n and does spjpi i 
ttie \ariations jriven to hirn hy nature, and thu- 

icciMiitilate tliem in any desired manner, lie thu- 

uhijits animals and nlants for liis r>;vn honefit (»i 
pleasure. He mav do this methodi(a!ly, or lie mav do i1 
uncon-.'iou'iy hy pre-c>rvinjr tlie individuals most usefu! 
( ) liiu) at the time, witliout any thoutrht of alterii:;; tin 
l'r« cd. It i". certain that he (an lar^'-ely influence tlw 
I haracter ot a iipeed hy Kelectinj;, in e.n h successive 
■ eiieration, individual ditference** so slitrht as to \h 

juito iiiaj)precialile hy an uneducated eve. 1 Itis jir(R'es« 
of '-election has Kten the aiT'-ncy in the prmluc- 
tion of the ijistinct and useful domestic hreeds. 

'"hat many <»f the lireeds produced hy man have to n 

artre extent the character of natural sjiecies, is shown 

>v the inextricahle <iouhts whether very many of their 
are varieties or ahori(;inal sper..:)S. 

There is no (dsvious reason why the jirinciplos whidi 
Save acted >o ef'i'iently uinler domestication should 

I'-t have acted uruler nature. In the preservation ol 
MS oured individuals and races, during the «;onstantly- 
'ccurreut Strui:::h' for I^visteine, we see the most 
powerful an<l eve.'--actiutr means of selection. 'Hi* 
striiiTi^le for existence inevilahly follows from the hijrli 
tjeonietrical ratio of incre^ise which is common to all 
or^-anic heing-s. This hijrh rate of increase i.s proved 
•ly calculation, — l,y the rapid increase «if many animal* 

md plants during a succes.sion of jHJci.liar sea.sons, or 
when naturalised in a new country. More individuals 
are l»orn thati can possihly survive. A errain in the 



t.,tiain«- will dpffriiime which individual shall live at •! 
wliirh shall die,— v^hich van»<ty or sixnioH shall iiicrca-. 
ill iiiiniher, and which shall docreaso, or finally Iwvome 
'itiiirt Ah the individuals of the Rame Hpecies come 

I! nil resp(>rt.« into the closest comj)etition with »'ach 
other, the strii:.'j;le will jfenerally he most sevt-re 

•I'tweeu lh<'m ; it wil' he almost e(|ually severe ^letweon 
the varieties of the same s[>ecies, and next in severity 
Wrtwoen the species of the same serins. Hut the 
■trii;r?le will often ho very Ke\ere hcluecn heintrs mo«.t 
remote in the s«aie of nature. I'he slightest advantage 
111 one l>eintr, at any nee or during: any season, over 
i.'ioso witli which it comes into competition, or Wtter 
i.i.iptatiori in however slijflit a de^Tee to the sur- 
roundinff physical conditions, will turn the halat>. e. 
\\'ith animals havintr separate*! sexes there will in 

iost cases he a Htriit'trle hetween the males for poswes- 
-loii of the females. llie most vigorous iiidividu;ils, or 
'tiuse winch have mont successfully stru^^'led with their 
"tnditions of life, will tfeiierally leave most protreny 
I'.ut success wiii often depend on havinjr special weapon- 
"C means of defence, or on the charms of tlie males : nn-' 

■ic sliijliteiit advantag'e will lead to victory 

As trcolotry plainly proclaims that each land tia.i 

undertrone tjreat physical chantres, we mi^hr have ex- 

[lected that orfranic heuijfs would have varied under 

nature, in the same way as they generally have varied 

•inder the chainred conditions of domestication. And if 

ti 're l*e any variahility under nature, it would Ix- an 

.laccountable fact if natural selection had not come 

Mto play. It }ia3 often been asserted, hut the assertiou 

" <iuite incapahle of proof, that the amount of vanatioi, 

wider nature is a strictly limited tjuantity. Mrin. 

thoutfh actsnp on external characters alone and ott.u 

ai>riciously, cm produce within a short f>eri>>d a g-reat 

result l»y adding up mere individual ditterences in lii- 

damc-Htif- productionH ; and every unc adiiiiU' lual there 

ire at iea>t individu.-il dilTerence> in species under 

mature, liut, besides guch differences, all naiuralisfx 

Nave Hdmitte<l the exi»ten<-e of vanetie-s, which thf^v 



' 'I 

4 -"J 

< s I UK oinciiv OK S|>K( IKS 


thin). - ifViririitly d'-^tinct to tip wnrtti) of rt'.nrd ;i 
ly-itiMiMi,! work?*. No ntir 'an draw aiiv rlcar (lis 
tiiii-tKiti lii'twi'oii iriHi' dir!. rfni'es atid <\\j)] ; or i.elwferi morf |il;iiiily inarknl \;ir'c le 
and •"jl>-<:j.(Mit'>j, and Hj.rcii-H. |>'l it Iw «)|.M.rv«-(i Imv 
iiif iirili-u ditfpr in th»' rank which tlipy a-- lmi ti 
tin- many repri'Heiitative fiTtrif- in Kur()|;e and Nortl 

If ttiHii we have uiidrr -latun' varialtility a-id ; 
pfiw»'rful atrrnt alway« ready to art and v,.le<t, wh' 
'ihmild HP doiiht thai varia'tnrm irj anv way iiMrtul ti 
lii'intrs, undtT tlirir exros-ively conndex relations n 
litiv wnuld l>o pH'sorved, ar<umulat«*d. and itiliented 
V^ iiv, if man ran hy |(atiiMicf> sph><-t \ar:aii(»n.H m-c 
tinrful to hiinoplt', should nature fail in Helectinjf varia 
tinn-^ u-pfiil, under charurinjr ('(niditionp of life, U 
her liviuif pr-.durt'! .' What liniit can l)f piit tn ttiii 
poAfr, aclitij.' diirini? loii^ a^oH and rijfidly Hrrut;rii-i;nj 
the whiile constitution, fitrurtiire, and hahitH of eacl 
creature. - fa\tiuriiie: the t'ood and rejecting the had 
I can set' no linut to thin {M>wer, in slowly and heauti 
fully adapt intf each form to the most complex relation! 
of jitc r]i.> theory of natural selection, even if w« 
looked no further thar» this, seems to me to he in itsel 
prohai.le. I have already recapitulated, M fairlv ax J 
could, the opp«i«ed dillirultie* and ol>jection9 : iu<vk lei 
us turn to the special facts and arj^umeutfi in favour o 
the theory. 

i )ii the vie« that species are only stronglv market! 
and |H'rmanent varieties, and that each s|>ecie« firsi 
ei Kfed as a variety, we rarj net why it ifl that no linf 
itt demanation can !>e drawn V»etween species, com- 
monly supposed to have ho«ni produ<pd hy special actf 
of creation, and varieties which are acknowledged tc 
have heen produced hy secondary laws. On this sam* 
'•iew we can understand bow it is that in each re*>ioi] 
where inanv species of a irenus have Iwen produced, 
and wjiere they now liourisli, tliese same sjHH-ies nhouid 
present many varieties ; for where the manufactory o^ 
species has heen active, we mijfht exj)e<t, a« a jfenera] 




KK( Arrn'LATlON AND ( ()N( IXSK »N 42.1 

r<iU'. to find it Ptili in actudi ; and tins is tlu- rasp if 
%.'iri»'tii'«< !)«• iiH'ipiciit sjK'cjpK. .M()r»Miv»T, tin* -jmv i«>~ of 

'h<' cliarniter of \arieli«': 

(itlur i>v .1 1»'»'> aTTiouiit ot' ditT»TPin"e tliati di> iht* ^\>* 

of «rii;tll»'r irciM'ra. Ilu* rlo-tlv allied s| 

1 ♦' lar:.'»>r tretiera. wliicli afford tlie trri'.tter mmil'»T of 
.Lrit'tif> i»r m(i|ii»'iit ^jm-.h—. rft.iiii to a ( t-rtaiii (ifi:r('t' 

for ihoy dii't-r from t-arli 
1itf»TPin"e tliati do ihf .>.i>«'i m«s 
I'lo-tly allied sjkm ;es aUo of 
tht' lartjer j^'Oiiera apparoiilly have restrn t»'d ranir<'^ 
:ii.d ill tln'ir atliiiiti«'.s thev are <lii-.t«>red in liUlt- krroujis 
round «)t}ier >ipe( ii's — ifi wliicli rt'spert** thoy' 
v,iri»'tie*. Ilieso are strai'tr** relations on t!io ^ icw oi 
omh s(»«M'ie^» liaviiig In't'ii indejMMidoiitly created, lnit 
;iri' ii'*<>l!i|;ililn if ail -jiecies first existed ;i.- \arietie.-. 

As tncli spe«Me^ tendM by itH jjeonietrnal ratio <it 
re[(r<>(iij(tion to iin'rease inordinately in niiinlier ; and 
i« till' riioditie<l desrendanL* of each speeiej- will In- 
''iiaiilcd to increase by so nuirh the more as tliey 
'M'come diversified in haliits and structure, imj as to t>e 
«'nal)le«] to seize on manv and widely different {>lare'» 
ill tlie ecotiomy of nature, there will l»e a consUmt 
teiidencv in natural selection to pre-sene the nio>t 
'iiverifent offspring of any one kjkh ies. Hence during: 
a lunir-continued course of modification, the slijrlit 
ditferences, characteristic of \arietie« of the same 
••jK>cieH, tend to he autfnionted into the greater differ 
•'iices characteristic of species of the same jjenus. New 
and improved vanetieH will inevitably supplant and 
exterminate the older, less improved and intermediate 
varieties ; and thus sjiecies are rendered to a lar^re extent 
detiiied and distinct ohje«ts. Pominant «pecies helontr- 
iiiif to the larjfer jrroups lend to jfive hirth to now and 
dominant forms; so that each larjfe ilT'iup tends to be- 
come still lartrer, and at the same time more di\er>fent 
in dianuter. Hut as all g-ro'ips cannot thu* succeed 
in iricre.isinir in size, for the world would not hold them, 
the more dominant jfroups l)oat the less dominant. 
I'his tendency in the lartre groups to ett on increaxinjr 
in sj^e and diverjfinff in character, totfcther with the 
almost inevitable contingency of much extinction, ex 
plains the arrau^^einent of all the forms of life, in 


^^- .a' f '■ o^.^>? ■ -■-', <r-ik^tu^ -M, ■ 'l^-. 



= i> 

;n'nup'< sulionliiiau- to tfrnup,, .ili v,ah'in a few trn-a 
(■l;u«<s«>s, which \ko now s»'f evervwliert- around us 
urnl has prevail.Ml throutrliout all time. Thi 
Hr.iud tact of the ffroupiritf of all ortfanic heiiur 
seems to me utterly inexplicable on the theorv o 
< reation. 

Am natural selection acts solely bv accumulatim 
'Ii^rht. successive, favourable varialioris'. it can [>ro(lur< 
no trn-at or suridcn moditicatio'i ; it can act only h\ 
\ cry short an.l slow stejis. Hence the canon of 'Natur; 
non facit saitum,' which every fresh addition to oui 
knowledt,'e tends to make truer, is on this theory simpls 
intelhirilde. We can plainly see why nature is prodiira 
in varu'ty, thouirh niLTirard in irniovation. IJut wlij 
this shouhl be a l.iw of nature if e ich species ha^ been 
iiuie[»endently created, no man cm explain. 

Many other facti are, a.s it seems to me, explicable 
on this theory. How stranjfe it is that a bird, undef 
the form of woodj.ecker, should have l)een created t(j 
prey on insects on the ground ; that upland ::eese. 
wliich never or rarely swim, should have U-en created 
with webbed feet ; that a thrush should have been 
create.l to dive and ft-e^l on sul>-aquatic insects; am' 
th;.t a petrel should have been cre.ited witli h iKit-s and 
structure fitting' it for the life of an auk ..r L'rel)e ! and 
so on 111 endless other cases. Uut on the view of each 
species constantly trying? to increase in number, with 
natural selection always ready to adapt the slowlv vary- 
irii,' <le-. eiidants of each t4» any unoccupied or ill-occu- 
pied f)lai-e in nature, these facts' to be strange, 
or perhaps mi:rht even have been anticipated. 

Ai natural selection .-.cts bv competition, it adapt- 
til. mhabiUints of each country tuily m relation to the 
de-ree of perfection of their' a-s^oiiatc- ; so that we 
need feel no surprise at tlie inhabitants of any one 
••ountry, althoui^h on th(> ordinary view .supposed to 
iiave been specially created and adapted for that coun- 
try, beiiitf beaten an.l supplanted by the naturalised 
productions from another land. Nor ought we to 
marvel if all the contrivance^ in nature be uot^ a." tar 


■i- 'l-^ 

^W ii\n:-- 



>- >u" jti(lu:»'. a^isolutely perfpct ; and if udme of 
thtTii l»e atthorront to our iilf.m of fitness. ^^'»> iieesi 
nor ni.irvel at the stinjf of tlie bee causing' the bei'H 
iivti death ; at drones heiii.' produred in .siii h \aHt 
li iiiihtTH for oi;f sintrlc n t, with t}ie jfreat majoritv 
-i.iiichtered by their sterile sistors ; at the ;i.-tonishii;< 
vsasto of pollen by our tir-trees ; at the in.stinctiv«s 
hatred of the (Hieeii bee for lier own fertile daujfhters , 
it ichnennionidit* feedinir within the live boilies ol 

■ atcrpilLars ; and at other such casen. 'Die wonder 
Muleeil is, on the theory of natural selection, thai 
more oases of the want of absolute j)erfe«-tion have not 
!>een observed. 

Tlie complex and little known laws iroverninK varia- 
tion are the same, as far as we can see, with the laws 
whiih have governed the prodiution of so-ealled specific 
. orms. In both rases physical conditions seem to have 
produced but littlr direct effect ; yet when varieties 

■ nter any zone, they occaHionally assume some of the 
1 h.iracters of the species proper to that zone. In Ivpth 
varieties and species, and disuse seem to have pro- 
il iced some effect ; for it is difficult to resist this con- 
(lusion when we look, for instance, at the lo({'|^er-hcade<t 
luck, which ha.s wiuj^s incapable of Hitrht, in nearly 
he Hiime condition as in the domestic duck ; or when 

>*> look at the burrowiiiij tucutucu, which is occasionally 
hlind, and tlien at certain moles, which are habitually 
'il;:id and have their eyes covered with skm ; or when 
■*H look at the blind animals inhabitinir the dark cav«vs 

>t .Vmerica and Europe. In both varietie^s and species 
I orrelation of jfrowth soems Ut have plaveil a most im- 
fXirtaiit part, so that when one pan h;is i>een modirte<l 

•ther parts are neceasarily mudilied. In both varieties 
^..'1(1 species reversions to lon^f-lost characters occur 
How inexpLcable on the theory of creation is the o<ca 
^ onal appearance of stri}>es on the shoulder and Ie^« 

■r the several s[>ecies of the horse-eenus and in their 
.'iybrids I How simply is this fact explained if we 
'"elieve that these species have descende*! from a striped 
,' ■o^euitor, in the same manner su) the wver*! JomeatK 







5 f 

hr»'«''l- of pi;r»c)i, hiivo (losccnfi»'»l from 'lii> Mii»' ind 
!iarr»'»J ro, k-pi'jpor) ' 

< >n tlit» (trfliii.'irv view ot ♦'ach s|i««cu'- lia\iiij.' l>f«'ii 
iii(U'i>''ri(ipntly iTf-atcd, why -hould Uu* sjM'cifii- clinrar- 
t«'r'«. or tlu>se hy winch the »|>t*rien of the sanip t'emiN 
rliHcr frnni e;ich ulhor, Ik* more variaMo tlian the 
^■eiu'ric el; ira<;t«rn in whirh tli«^y .ill aijree ; ^^ hv, for 
in<t;in( •', should tlie colour of a flower Im» more likely 
to \:ir\ ;ri any one wperievi of a treiius, if the otlier 
H}). 'P'i, sint]>ose«l to have heen creiit*«l iiide|»eii(leiitly, 
havB dirifereiitly coloured flowers, than if all the >i|>erieH 
of the i:eriii» have the name coloured flowern .^ If speries 
are only well-inarke<l varieties, of which the characters 
have l>ec(>me in a hi^rh deji^ree i>ermanent, we 
mider«taiid this fact ; for they have alreailv varied 
"tince thev hranche<l off from a common pro^j^enilor 
iu certain characters, hy which they have come to he 
sp«'cificallv distinct from each other ; and therefore 
these -ame characters would Ke more likely still to Ik» 
variahle than the a^eneric characteni which have Keen 
inherited without cliantf»» for an enormou* [»erio<l. It 
it inexjilicahle on the theorv of creation why a part 
rievelojHMl iti a verv unusual manner in any one s|>e«-ies 
of n <r»'r\us, and therefore, ax we may naturally infer, 
of g-reat importance to the H|)ecies, should J»e eminently 
liahle to variation ; but, on my view, this part has 
undergone, since the twweral Bpecies hranche<i off from 
a common [irogenitor. an unusual amount of variahility 
and mod'tiiafion, and therefore we might expect this 
part generally to he still variable. Ilut a part may l>e 
Hevelop'd in the most unusual manner, like the wing 
of a Iwt, and yet not be more variahle than any other 
Btaucture, if the part he common to many 8ulM»rdinate 
fonnx. that is, if it haa been inherited for a very lonjf 
period ; for in this case it wil! have l^een rendered 
con-tant hv long-c<mtinued natural selectifui. 

(ilancuu; at instincts. marveHnu* ai- s«)rn«» nr». the? 
offer no greater difficulty than doe* corporeal structure 
on the theory of tlie natural selection of successive, 
■liffht, but profitable modirtcationi. We ean thuf 


[{?:( AIMTI I.ATION AM) ( ()N( I.l'SK •% 4-7 

jnd<>rst.i!i<l wiy nature rnuveH \>y trailuatrd 8t»«ji<« in 
(Midiiw :iitr (lilffrerit aniiiialt nf ilio naine olas!* with tli"ir 
-ovcral iiistiiift)*. I lia\f> attpmjitj'd tf» show Imw nun h 
iicht thf priricijiU' of jfraiiatioii ihrnwfi on th«» mlmirahle 
ar(lut»'«tiiral |((>w»»r>* of the hivp-hee. Haint no douht 
HOinctimj'H ooriips into play in niodjfvirnf iifitincf* ; hut 
it (••.-♦aitily IS not in'iistK'iisahle, aa we »e^, in tho «a><o 
of iieuttT iii-oct*!, wliH-h leavp no progeny to inherit 
the effe<t-s of loinr-totitiuuod hahit. < hi the view of 
all the species of the name trenuH liaving de*<r»'iide(l 
from a cornnion parent, and having inh<-rit»Hl niinh 
in <-omniun, we <'jin understand iiow it i<i tliat allie<l 
«pe« u'H, when placeil under eonsiderahly different enn- 
riitions ot life, yet nhould follow nearly the K.irne 
instinct* ; why the thruHh of houtli Amenra, for 
inntance, lines her nest with mud like our British 
«{>ecie«. Oil the view of instincts having heen bIowIv 
ii(juire<l through natural selection we need not marvel 
it some instincts heing ap{tarently not jxirfect and 
lialile to mistakes, and at many instincts causing other 
animals to suffer. 

If species be only well-marked and jwrmanent varie- 
ties, we can at once see why their crossed offspring 
should follow the same complex laws in their degrees 
and kinds of ret<emhlance to their parents, — in l»eiug 
aiworljcd into each other by successive crosses, and in 
other such points, — as do the croHwed offspring of 
acknowledged varieties. On the other hand, thet-*' 
^ouid b« strange fact*) if species have been inde{>end- 
ently create<l, and varieties ha^e been produced by 
•^•condary laws. 

If we admit that the geological record is imfienVrt 
in an extreme degree, tlien such fact-* a^ the record 
ifives, 8UpjH».-t the the<»ry of descent with moditicatioti 
N'ew s[>«cies have come on the stage slowly and at 
successive intervals ; and the amount of change, after 
eijua! iuterviila nf time, is widely different in differeiit 
"he extinction of st»«cies and of whole groui 



of s|>ecies, which has pl.iyed so conspicuous a {»art in the 
history of the organic world, almost inevitably followi 





■ 11 t: •' principle of »ol«'<:lii.ii ; fur <»1«1 form;* wili 
t>o (iup|il:iiitp<l !))• ru'W .-iiiij improved torms. N<Mtln r 
-iritrit? -pf ie.« nor Kroup-^ of •.ppcips r»>.ipp«".ir wli^ii iht> 
( <>t oniiiiiiry u'eneration Jian once lireri liruken. 
riie trraijiial ditf iisioii of ilomiiiaiit form'-, with the hIow 
mi»iiiticaiii»ri ot" th«'ir descen«laiit>j, cau-cs the forniH nf 
li;f>, after ioiitr intervals of time, to ap[»ear lut if they 
lia.l chaiiired >niiiiltaneou»ly thron^fhout the world, 
i'lii" fact of the fossil remauiH of each formation In-ing 
in some lituTce terrnediate in character hetween the 
fr)s.sil8 in the formation.^ ahove and lielow, 18 simply 
""xplained hv tlieir intermediate position iu the chain 
ot de.-cent. The jfrand fact that .ill extinct orjfanic 
ln'intfM helon^f to tlie same systeru witfi recent r)einff8, 
tallint; either into the same or into intermediate trroup-, 
tollow-t from the liviiitr ami the extinct benitr t'u^ 
oti>jprin;f of common parents A- tiie jrroups which 
have descended from an ancient pro;renitor have tfener- 
tllv diverired in character, the pro^renitnr witli its e^irly 
descendants will often he intermediate ii\ character iti 
■oni|>;irison with it,s later descendant'^ ; .ind thus v*.- 
can see whv the more ancient a fossil is. the oftener 
«t:irids in some deirree intermediate between existinu' 
and allied groups. Itecent forms are tc^'H'Tally looke«l 
i' A>- In iiiL', in some v:i;rue sense, higher than ancient 
.nd extinct forms; and thev are in so tar hieher an 

he later and more improved forms liave conqtuTcd the 
i.hler and less improved organic lK?in>js in the struggle 
Mjr lif»'. Ui^tly, the law of tlie hmc: endurance ol 
lUict t'nim.^ o.i tlie same continent. .f niarsuj)ial!» in 
Ati<tralia, of edciitata in America, and such 
case.s, — IS iiitelli^rihle^ f,,r within a confined > uuntry, 

he recent and the extinct will naturally be allied 
Ity descent 

I.ookiii;:' to i.'cot;ra[diicai di-trihution, if we admi* 
tiiat ihere h.a.s heen dumiif the lo:i^' course of a^'es 

7::Ui n ITi:;; ; .iv;'.>i; i:;;::: vr::c p.i: ■- •--i i:;v -»•_': m I'.- n-: 

owintr tt> former climatal and jfeojjraphical chances 
md to the many occ;i*ional and uuknoHn means of 
dispervtl, then »»e can iindo-.-find, on the theory oi 




■Icjueiil with modification, nnwt of tli« jrroat lea<liiu 
fal■^« III ni-triliiition. W v can hee why tlit>r»' hIiohIiI U 


trikiii? a itarcllt'lisin in tlie distriiiutiuii ot 


tw'iies throu^'liu'Jl K[»aro, nii'l in thoir >f«'ol(n:ical suc- 

'•essioii throujfliout time ; for i:i lioth oases the lioi"i;rH 

have lK}eri ronnerted hy the l*oiid of ordinary ifeinTa- 

t on, and tlio niranii of nio«lifi. atiori have i»eeii the 

•nine \V e -in; tiio full rneaniiitf of the wundcrful 

•n-t, whirh must have Htruck every traveller, narnelv, 

li;it on the name continent, under the most diverse 

iinditionn, under heat and cold, on nioiiiiLiin ami 

iwland, on dosertH and mar-hes, mo-t of the inhabit 

tilts within earh jrreat tl;i>s are plainly related ; fo' 

'hey 'ill jfenerally l>e destendantj^ of the same j>ro 

;.'eiiitorH and early colonistH. On thix name |irinci|d» 

of former mijf ration, comhined in most ca-ies witi; 

•nodification, we ean iindersUind, hy the aid of the 

•Jlai'ial jM'rio*!, the identity of s(»me few planti, and 

he (hwe alliance of many others, «mi the most dutaii* 

• M iiitaiiiH, under the most different climates ; and 
ikewise the close alliance of some of the inhabitant-* 
■f the sea in the northern and southern temperate 

/ones, thou^rh separiiled hy the whole intertropical 

• iceau. Althoin.'h two area* may present the Bame 
physical conditions of life, we need fe«'I no surprise at 
Uieir inhahitants heiii)? widely different, if they have 
! '-en for a lonp period completely separated from eacli 
other; for a:) the relation of ortranism t«» orjranism is 
l!ie most important of all relations, and aH the two 
ireas will have received colonist/) from sonie thin! 
-ource or from e;ich other, at various fieriods and in 
'litfereut proportions, the course of modification in tlie 
*wn areas will inevital)ly l»e different. 

<>n this view of nii^rratiou, with suh^e^lllor;t modifica- 
tion, we can see why oceanic islands Hliould he iiihahited 
iiy ivw species, but of the>e, that many should he 
l>eculiar. We can clearly see why those aninial- 
whuh cannot cross wide sjaces of ocean, as fro^'^s 
and terrestrial mammals, phould uot inhal'it fM-eanic 
islands; and why, on the other hand, new and pe.uliar 







ON niK OK I (.IN OK H1'K< IK"* 

.|.f«i»-' of luitM, which rail traverse the ocpaii, slioiilil 
«(i ot\rii he foiiiul nil ixUihIh ili^Uiit frr)ni .iii\ 
, (Uitjii«-!il. Such facU a.H th« |)rowMi.« of (..». uli»i 
«iMTU"* of hrtlx, .-iinl ihp al«»»'!ii«» of all other ni.iminalH 
oil o. iMiiic JHlaiult, ar«» utterly in«'xi.lir;ihle on lh» 
lli«»<irv of iiidrinMidi'iit a< ;» of <r«'.itioii. 

Th.' t'xi-t.'ii. e of do-ely allied or rej.resonUtivi 
jiKMii's ill aiiv two areji-, iinplu"*, on the thenrr o 
(i»-»,.»Mil with intMliiHMtioM, LliHl the <ime juri-nt- for 
merly iiiliJtt.iu-<l lM)th are.-is . ami we almost iiivariahli 
fimi Ihat wherever ru.tiiv clo«ely allie.l aperies inhahi 
two areas, somu loiilital npecies iDriimou t<» hotli stil 
«\i-t. Wherever many (•l»»sely allie.1 yet <ii<tinc 
Hpei-ies oiour, many douhlful forms and virieties o 
the H^nrie speeies. likewi>ie <M-ciir. It is a rule of hij;! 
ffeiierality that the inhahitiiit- of each area are relate< 
to the inliahitants of the iie.aresl Hoiino wheiit-e iinmi 
^'rantH mi^ht have Ikm-ii derived. \Ve nee tlii* ii 
nearly all the plaiitx and animals of the (Jalipajjo 
Ar<lnpel;i^'o, of Juan Fernandez, and of the othe 
Aineriraii island;, hcint: rehitwl in tiie most strikii)| 
manner to the plants and animals of the neiK'lihouriiij 
American m.iinland ; and th(we of lh.> (ape de Verd 
Ar«iii(K'lauo and other African islands U) the Africa: 
mainl 4inl. It must be admitted that these fads re< eiv 
no explanation on the theory of creation. 

The fa<-t, as we have seen, that all iKist and pre.^11 
ortfHtiic Immiic* constitute one -rraiid natural system 
with tfroup sulM»rdiiiate to trroup, ami with extint 
firroups otteii falling in hetwe»>n recent groups, is it 
terniril>io on the theory of natural selei tioii with il 
ct>ntii.;,'enoies of extinction and divergence of chai 
acter. On these siime principles we ^'e how it ii 
that the mutual .itrmities of the species and tfeiiei 
within each c!:i«s .ire so complex and circuitous. W 
see why certain characters are far more serviceahl 
than others for cl;issifi. ation ; - why adaptive cha 
ictcr-, thoiitrh of (.aramount importiiue to The i.euu 
are of hardly .tiiy import-'ince in classiti<ati«»n ; wh derived from rudimenta-y jiart-^. liiou^'h 1 






ho M"-\ii»j Ui the lK«iinf, are often of hiifli c la>wif;ratiirv 
».»iii«'; ;»ti<l wliv erntir\ iilnj^'.-.i! characfiTs .irt* tlie trm^i 
.itiii,il>l»« <•» all. Tiie real aJftintien of all urifaiiii Kt'iinfs 
at>' line t«» iiihcrititiife or roiiimufiity «»f «l(wi«.nf The 
iiitiiral t»v>.ti«n) m n t'l-iM-aJoL'tial arraiufPiiu-nt. in v*liirh 
*f have »M iliscnvfr tht< Iiium ot (i«««i ••iit l>\ tlu' tiuwl 
fn'rrnain'iit ilianwUirh, however -Ii!;!!! th«'ir iin- 
I'orUi.f e riiav \>vi. 

l'}io Iraiiifwork of iMH.fs hfiiiir th.. ^^itiie iii tii»* h.uiii 
ot a rnaii, wiii;; of a l>at, fin of the {Ktrpoisr, and li-^' of 
tli»« hor-f. the •i.ttni' nn nht»r of \«'rt«>lirii« fi'riiii:,^;- th»» 
iiHik of the jfirifif ami cf tlie el.'pliaiit, ami iniiurner 
a'lje (ither H\uh fa.tjt, at onre explain tii«'rn.m>lM^ on 
tiip tfio<try of (Jo-.! f nt witli nlnw and slijrlit «in( t'4«ivc 
iMi»difioat oi'H. 'I'h«« .^uiularity of pattt-ru in tiif winjf 
i\ui\ Icif of a hat, though ii^ed for hucIi ditformt 
('iiriwi>«', — in the jaws and 1«'4.'h of a crah, — in the 
|M'i;iN, stameuM, and plstiU of a flower, \» likewise 
int»'llit:il>le on the view of tho tfrad'ial moditi.ation 
ot partri or orjfan-*, whii li wi-re alike in the e-iirly 
prui^iMiitor of eavh flans. ( )ii the prinriple <if stuN-e*- 
«ivo vari.ifimH ni»t always superveniiitr at an Marlv 
.i:rp, and ht'inir inherited at a corre.sjxniili.Mir not early 
p«'rio(l of life, we oan clearly )*ee why the eiiihryoh 
i>f mainmalu, hinls, reptiles, and fishes xliould U> no 
tlo»ely alike, and should l>e so unlike the adult forms. 
\N e may iea<.e niarvellirnf at the emhryo of an air- 
hr«vithin>f mammal or hird havjnir hraiuhial slit.s and 
artt-ries runninjf in loops, like iho.^e in a fi>h whii h 
h;w to hreathe the air dirisolved in water, by the aid of 
well -developed hran«hi>e. 

Disuse, aided .•.nfoftimi's l;y natural selertion, will 
often lend to reduce an or^an, when it ha.s ln-inrnM 
useless Ity rliaiitfed hahit« or under rhaiiifed conditions 
of lite; and »»• can c