Withtheincreasedordiminishedlengthofthebeakthelengthoftheslitformingtheexternalorificeofthenostrilsvaries，butnotindueproportion，for，takingtherock—pigeonasthestandard，theorificeinaShort—facedTumblerwasnotshortenedindueproportionwithitsveryshortbeak。Ontheotherhand（andthiscouldnothavebeenanticipated），theorificeinthreeEnglishCarriers，intheBagadottenCarrier，andinaRunt（pigeoncygne），waslongerbyabovethetenthofaninchthanwouldfollowfromthelengthofthebeakproportionallywiththatoftherock—pigeon。InoneCarriertheorificeofthenostrilswasthriceaslongasintherock—
pigeon，thoughinbodyandlengthofbeakthisbirdwasnotnearlydoublethesizeoftherock—pigeon。Thisgreatlyincreasedlengthoftheorificeofthenostrilsseemstostandpartlyincorrelationwiththeenlargementofthewattledskinontheuppermandibleandoverthenostrils;andthisisacharacterwhichisselectedbyfanciers。Soagain，thebroad，naked，andwattledskinroundtheeyesofCarriersandBarbsisaselectedcharacter;andinobviouscorrelationwiththis，theeyelids，measuredlongitudinally，areproportionallymorethandoublethelengthofthoseoftherock—pigeon。
Thegreatdifference（seefigure27）inthecurvatureofthelowerjawintherock—pigeon，theTumbler，andBagadottenCarrier，standsinobviousrelationtothecurvatureoftheupperjaw，andmoreespeciallytotheangleformedbythemaxillo—jugalarchwiththepremaxillarybones。ButinCarriers，Runts，andBarbsthesingularreflexionoftheuppermarginofthemiddlepartofthelowerjaw（seefigure25）isnotstrictlycorrelatedwiththewidthordivergence（asmaybeclearlyseeninfigure26）ofthepremaxillarybones，butwiththebreadthofthehornyandsoftpartsoftheuppermandible，whicharealwaysoverlappedbytheedgesofthelowermandible。
InPouters，theelongationofthebodyisaselectedcharacter，andtheribs，aswehaveseen，havegenerallybecomeverybroad，withtheseventhpairfurnishedwithprocesses;thesacralandcaudalvertebraehavebeenaugmentedinnumber;thesternumhaslikewiseincreasedinlength（butnotinthedepthofthecrest）by。4ofaninchmorethanwouldfollowfromthegreaterbulkofthebodyincomparisonwiththatoftherock—pigeon。InFantails，thelengthandnumberofthecaudalvertebraehaveincreased。
Hence，duringthegradualprogressofvariationandselection，theinternalbonyframeworkandtheexternalshapeofthebodyhavebeen，toacertainextent，modifiedinacorrelatedmanner。
Althoughthewingsandtailoftenvaryinlengthindependentlyofeachother，itisscarcelypossibletodoubtthattheygenerallytendtobecomeelongatedorshortenedincorrelation。ThisiswellseeninJacobins，andstillmoreplainlyinRunts，somevarietiesofwhichhavetheirwingsandtailofgreatlength，whilstothershavebothveryshort。WithJacobins，theremarkablelengthofthetailandwing—feathersisnotacharacterwhichisintentionallyselectedbyfanciers;butfanciershavebeentryingforcenturies，atleastsincetheyear1600，toincreasethelengthofthereversedfeathersontheneck，sothatthehoodmaymorecompletelyenclosethehead;anditmaybesuspectedthattheincreasedlengthofthewingandtail—feathersstandincorrelationwiththeincreasedlengthoftheneck—
feathers。Short—facedTumblershaveshortwingsinnearlydueproportionwiththereducedsizeoftheirbodies;butitisremarkable，seeingthatthenumberoftheprimarywing—feathersisaconstantcharacterinmostbirds，thattheseTumblersgenerallyhaveonlynineinsteadoftenprimaries。Ihavemyselfobservedthisineightbirds;andtheOriginalColumbarianSociety（5/37。J。M。Eaton’Treatise’edition1858page78。）
reducedthestandardforBald—headTumblersfromtentoninewhiteflight—
feathers，thinkingitunfairthatabirdwhichhadonlyninefeathersshouldbedisqualifiedforaprizebecauseithadnottenWHITEflight—
feathers。Ontheotherhand，inCarriersandRunts，whichhavelargebodiesandlongwings，elevenprimaryfeathershaveoccasionallybeenobserved。
Mr。Tegetmeierhasinformedmeofacuriousandinexplicablecaseofcorrelation，namely，thatyoungpigeonsofallbreedswhichwhenmaturebecomewhite，yellow，silver（i。e。，extremelypaleblue），ordun—coloured，arebornalmostnaked;whereaspigeonsofothercoloursarebornwell—
clothedwithdown。Mr。Esquilant，however，hasobservedthatyoungdunCarriersarenotsobareasyoungdunBarbsandTumblers。Mr。Tegetmeierhasseentwoyoungbirdsinthesamenest，producedfromdifferentlycolouredparents，whichdifferedgreatlyinthedegreetowhichtheywereatfirstclothedwithdown。
Ihaveobservedanothercaseofcorrelationwhichatfirstsightappearsquiteinexplicable，butonwhich，asweshallseeinafuturechapter，somelightcanbethrownbythelawofhomologouspartsvaryinginthesamemanner。Thecaseis，that，whenthefeetaremuchfeathered，therootsofthefeathersareconnectedbyawebofskin，andapparentlyincorrelationwiththisthetwooutertoesbecomeconnectedforaconsiderablespacebyskin。IhaveobservedthisinverymanyspecimensofPouters，Trumpeters，Swallows，Roller—tumblers（likewiseobservedinthisbreedbyMr。Brent），andinalesserdegreeinotherfeather—footedpigeons。
Thefeetofthesmallerandlargerbreedsareofcoursemuchsmallerorlargerthanthoseoftherock—pigeon;butthescutellaeorscalescoveringthetoesandtarsihavenotonlydecreasedorincreasedinsize，butlikewiseinnumber。Togiveasingleinstance，IhavecountedeightscutellaeonthehindtoeofaRunt，andonlyfiveonthatofaShort—facedTumbler。Withbirdsinastateofnaturethenumberofthescutellaeonthefeetisusuallyaconstantcharacter。Thelengthofthefeetandthelengthofthebeakapparentlystandincorrelation;butasdisuseapparentlyhasaffectedthesizeofthefeet，thiscasemaycomeunderthefollowingdiscussion。
ONTHEEFFECTSOFDISUSE。
Inthefollowingdiscussionontherelativeproportionsofthefeet，sternum，furculum，scapulae，andwings，Imaypremise，inordertogivesomeconfidencetothereader，thatallmymeasurementsweremadeinthesamemanner，andthattheyweremadewithouttheleastintentionofapplyingthemtothefollowingpurpose。
[TABLE5。I。
PIGEONSWITHTHEIRBEAKSGENERALLYSHORTERTHANTHATOFTHEROCK—PIGEON，PROPORTIONALLYTOTHESIZEOFTHEIRBODIES。
Column1。NameofBreed。
Column2。ActuallengthofFeet（inches）。
Column3。Differencebetweenactualandcalculatedlengthoffeet，inproportiontolengthoffeetandsizeofbodyintheRock—pigeon。
Column3a。Tooshortby（inches）。
Column3b。Toolongby（inches）。
1。2。3a。3b。
Wildrock—pigeon（meanmeasurement）。2。02
Short—facedTumbler，bald—head。1。570。11……
Short—facedTumbler，almond。1。600。16……
Tumbler，redmagpie。1。750。19……
Tumbler，redcommon（bystandardtoendoftail）。1。850。07……
Tumbler，commonbald—head。1。850。18……
Tumbler，roller。1。800。06……
Turbit。1。750。17……
Turbit。1。800。01……
Turbit。1。840。15……
Jacobin。1。900。02……
Trumpeter，white。2。020。06……
Trumpeter，mottled。1。950。18……
Fantail（bystandardtoendoftail）。1。850。15……
Fantail（bystandardtoendoftail）。1。950。15……
Fantailcrestedvar。Ditto。1。950。00。0
IndianFrill—backDitto。1。8O0。19……
EnglishFrill—back。2。100。03……
Nun。1。820。02……
Laugher。1。650。16……
Barb。2。000。03……
Barb。2。00……
0。03
Spot。1。900。02……
Spot。1。900。07……
Swallow，red。1。850。18……
Swallow，blue。2。00……
0。03
Pouter。2。42……
0。11
Pouter，German。2。30……
0。09
BussorahCarrier。2。17……
0。09
Numberofspecimens。28225
Imeasuredmostofthebirdswhichcameintomypossession，fromthefeatheredBASEofthebeak（thelengthofbeakitselfbeingsovariable）totheendofthetail，andtotheoil—gland，butunfortunately（exceptinafewcases）nottotherootofthetail;Imeasuredeachbirdfromtheextremetiptotipofwing;andthelengthoftheterminalfoldedpartofthewing，fromtheextremityoftheprimariestothejointoftheradius。I
measuredthefeetwithouttheclaws，fromtheendofthemiddletoetotheendofthehindtoe;andthetarsusandmiddletoetogether。Ihavetakenineverycasethemeanmeasurementoftwowildrock—pigeonsfromtheShetlandIslands，asthestandardofcomparison。Thefollowingtableshowstheactuallengthofthefeetineachbird;andthedifferencebetweenthelengthwhichthefeetoughttohavehadaccordingtothesizeofbodyofeach，incomparisonwiththesizeofbodyandlengthoffeetoftherock—
pigeon，calculated（withafewspecifiedexceptions）bythestandardofthelengthofthebodyfromthebaseofthebeaktotheoil—gland。Ihavepreferredthisstandard，owingtothevariabilityofthelengthoftail。
ButIhavemadesimilarcalculations，takingasthestandardthelengthfromtiptotipofwing，andlikewiseinmostcasesfromthebaseofthebeaktotheendofthetail;andtheresulthasalwaysbeencloselysimilar。Togiveanexample:thefirstbirdinthetable，beingaShort—
facedTumbler，ismuchsmallerthantherock—pigeon，andwouldnaturallyhaveshorterfeet;butitisfoundoncalculationtohavefeettooshortby。11ofaninch，incomparisonwiththefeetoftherock—pigeon，relativelytothesizeofthebodyinthesetwobirds，asmeasuredfromthebaseofbeaktotheoil—gland。Soagain，whenthissameTumblerandtherock—pigeonwerecomparedbythelengthoftheirwings，orbytheextremelengthoftheirbodies，thefeetoftheTumblerwerelikewisefoundtobetooshortinverynearlythesameproportion。Iamwellawarethatthemeasurementspretendtogreateraccuracythanispossible，butitwaslesstroubletowritedowntheactualmeasurementsgivenbythecompassesineachcasethananapproximation。
TABLE5。II。
PIGEONSWITHTHEIRBEAKSLONGERTHANTHATOFTHEROCK—PIGEON，PROPORTIONALLYTOTHESIZEOFTHEIRBODIES。
Column1。NameofBreed。
Column2。ActuallengthofFeet（inches）。
Column3。Differencebetweenactualandcalculatedlengthoffeet，inproportiontolengthoffeetandsizeofbodyintheRock—pigeon。
Column3a。Tooshortby（inches）。
Column3b。Toolongby（inches）。
1。2。3a。3b。
Wildrock—pigeon（meanmeasurement）。2。02
Carrier。2。60……
0。31
Carrier。2。60……
0。25
Carrier。2。40……
0。21
Carrier，Dragon。2。25……
0。06
BagadottenCarrier。2。80……
0。56
Scanderoon，white。2。80……
0。37
Scanderoon，Pigeoncygne。2。85……
0。29
Runt。2。75……
0。27
Numberofspecimens。8……8
Inthesetwotables（Tables5。I。and5。II。）weseeinthefirstcolumntheactuallengthofthefeetinthirty—sixbirdsbelongingtovariousbreeds，andinthetwoothercolumnsweseebyhowmuchthefeetaretooshortortoolong，accordingtothesizeofbird，incomparisonwiththerock—
pigeon。Inthefirsttabletwenty—twospecimenshavetheirfeettooshort，onanaveragebyalittleabovethetenthofaninch（viz……107）;andfivespecimenshavetheirfeetonanaverageaverylittletoolong，namely，by。07ofaninch。Butsomeoftheselattercasescanbeexplained;forinstance，withPoutersthelegsandfeetareselectedforlength，andthusanynaturaltendencytoadiminutioninthelengthofthefeetwillhavebeencounteracted。IntheSwallowandBarb，whenthecalculationwasmadeonanystandardofcomparisonbesidestheoneused（viz。lengthofbodyfrombaseofbeaktooil—gland），thefeetwerefoundtobetoosmall。
Inthesecondtablewehaveeightbirds，withtheirbeaksmuchlongerthanintherock—pigeon，bothactuallyandproportionallywiththesizeofbody，andtheirfeetareinanequallymarkedmannerlonger，namely，inproportion，onanaverageby。29ofaninch。IshouldherestatethatinTable5。I。thereareafewpartialexceptionstothebeakbeingproportionallyshorterthanintherock—pigeon:thusthebeakoftheEnglishFrill—backisjustperceptiblylonger，andthatoftheBussorahCarrierofthesamelengthorslightlylonger，thanintherock—pigeon。ThebeaksofSpots，Swallows，andLaughersareonlyaverylittleshorter，orofthesameproportionallength，butslenderer。Nevertheless，thesetwotables，takenconjointly，indicateprettyplainlysomekindofcorrelationbetweenthelengthofthebeakandthesizeofthefeet。Breedersofcattleandhorsesbelievethatthereisananalogousconnectionbetweenthelengthofthelimbsandhead;theyassertthatarace—horsewiththeheadofadray—horse，oragrey—houndwiththeheadofabulldog，wouldbeamonstrousproduction。Asfancypigeonsaregenerallykeptinsmallaviaries，andareabundantlysuppliedwithfood，theymustwalkaboutmuchlessthanthewildrock—pigeon;anditmaybeadmittedashighlyprobablethatthereductioninthesizeofthefeetinthetwenty—twobirdsinthefirsttablehasbeencausedbydisuse（5/38。Inananalogous，butconverse，manner，certainnaturalgroupsoftheColumbidae，frombeingmoreterrestrialintheirhabitsthanotheralliedgroups，havelargerfeet。SeePrinceBonaparte’Coupd’oeilsurl’OrdredesPigeons。’），andthatthisreductionhasactedbycorrelationonthebeaksofthegreatmajorityofthebirdsinTable5。I。When，ontheotherhand，thebeakhasbeenmuchelongatedbythecontinuedselectionofsuccessiveslightincrementsoflength，thefeetbycorrelationhavelikewisebecomemuchelongatedincomparisonwiththoseofthewildrock—pigeon，notwithstandingtheirlesseneduse。
AsIhadtakenmeasuresfromtheendofthemiddletoetotheheelofthetarsusintherock—pigeonandintheabovethirty—sixbirds，Ihavemadecalculationsanalogouswiththoseabovegiven，andtheresultisthesame——
namely，thatintheshort—beakedbreeds，withequallyfewexceptionsasintheformercase，themiddletoeconjointlywiththetarsushasdecreasedinlength;whereasinthelong—beakedbreedsithasincreasedinlength，thoughnotquitesouniformlyasintheformercase，fortheleg，insomevarietiesoftheRuntvariesmuchinlength。
LENGTHOFSTERNUM。
Asfancypigeonsaregenerallyconfinedinaviariesofmoderatesize，andasevenwhennotconfinedtheydonotsearchfortheirownfood，theymustduringmanygenerationshaveusedtheirwingsincomparablylessthanthewildrock—pigeon。Henceitseemedtomeprobablethatallthepartsoftheskeletonsubservienttoflightwouldbefoundtobereducedinsize。Withrespecttothesternum，Ihavecarefullymeasureditsextremelengthintwelvebirdsofdifferentbreeds，andintwowildrock—pigeonsfromtheShetlandIslands。FortheproportionalcomparisonIhavetriedthreestandardsofmeasurement，withalltwelvebirdsnamely，thelengthfromthebaseofthebeaktotheoil—gland，totheendofthetail，andfromtheextremetiptotipofwings。Theresulthasbeenineachcasenearlythesame，thesternumbeinginvariablyfoundtobeshorterthaninthewildrock—pigeon。Iwillgiveonlyasingletable，ascalculatedbythestandardfromthebaseofthebeaktotheoil—gland;fortheresultinthiscaseisnearlythemeanbetweentheresultsobtainedbythetwootherstandards。
TABLE5。III。
LENGTHOFSTERNUM。
Column1。NameofBreed。
Column2。ActualLengthinInches。
Column3。Tooshortby（inches）。
1。2。3。
WildRock—pigeon。2。55
PiedScanderoon。2。800。60
BagadottenCarrier。2。800。17
Dragon。2。450。41
Carrier。2。750。35
Short—facedTumbler。2。050。28
Barb。2。350。34
Nun。2。270。15
GermanPouter。2。360。54
Jacobin。2。330。22
EnglishFrill—back。2。400。43
Swallow。2。450。17
Thistable（Table5。III。）showsthatinthesetwelvebreedsthesternumisofanaverageone—thirdofaninch（exactly。332）shorterthanintherock—
pigeon，proportionallywiththesizeoftheirbodies;sothatthesternumhasbeenreducedbybetweenone—seventhandone—eighthofitsentirelength;andthisisaconsiderablereduction。
Ihavealsomeasuredintwenty—onebirds，includingtheabovedozen，theprominenceofthecrestofthesternumrelativelytoitslength，independentlyofthesizeofthebody。Intwoofthetwenty—onebirdsthecrestwasprominentinthesamerelativedegreeasintherock—pigeon;insevenitwasmoreprominent;butinfiveoutoftheseseven，namely，inaFantail，twoScanderoons，andtwoEnglishCarriers，thisgreaterprominencemaytoacertainextentbeexplained，asaprominentbreastisadmiredandselectedbyfanciers;intheremainingtwelvebirdstheprominencewasless。Henceitfollowsthatthecrestexhibitsaslight，thoughuncertain，tendencytobereducedinprominenceinagreaterdegreethandoesthelengthofthesternumrelativelytothesizeofbody，incomparisonwiththerock—pigeon。
Ihavemeasuredthelengthofthescapulainninedifferentlargeandsmall—sizedbreeds，andinallthescapulaisproportionallyshorter（takingthesamestandardasbefore）thaninthewildrock—pigeon。Thereductioninlengthonanaverageisverynearlyone—fifthofaninch，oraboutone—ninthofthelengthofthescapulaintherock—pigeon。
ThearmsofthefurculainallthespecimenswhichIcompared，divergedless，proportionallywiththesizeofbody，thanintherock—pigeon;andthewholefurculumwasproportionallyshorter。ThusinaRunt，whichmeasuredfromtiptotipofwings381/2inches，thefurculumwasonlyaverylittlelonger（withthearmshardlymoredivergent）thaninarock—
pigeonwhichmeasuredfromtiptotip261/2inches。InaBarb，whichinallitsmeasurementswasalittlelargerthanthesamerock—pigeon，thefurculumwasaquarterofaninchshorter。InaPouter，thefurculumhadnotbeenlengthenedproportionallywiththeincreasedlengthofthebody。
InaShort—facedTumbler，whichmeasuredfromtiptotipofwings24
inches，thereforeonly21/2incheslessthantherock—pigeon，thefurculumwasbarelytwo—thirdsofthelengthofthatoftherock—pigeon。]
Wethusclearlyseethatthesternum，scapula，andfurculumareallreducedinproportionallength;butwhenweturntothewingswefindwhatatfirstappearsawhollydifferentandunexpectedresult。ImayhereremarkthatI
havenotpickedoutspecimens，buthaveusedeverymeasurementmadebyme。
Takingthelengthfromthebaseofbeaktotheendofthetailasthestandardofcomparison，Ifindthat，outofthirty—fivebirdsofvariousbreeds，twenty—fivehavewingsofgreater，andtenhavethemoflessproportionallength，thanintherock—pigeon。Butfromthefrequentlycorrelatedlengthofthetailandwing—feathers，itisbettertotakeasthestandardofcomparisonthelengthfromthebaseofthebeaktotheoil—
gland;andbythisstandard，outoftwenty—sixofthesamebirdswhichhadbeenthusmeasured，twenty—onehadwingstoolong，andonlyfivehadthemtooshort。Inthetwenty—onebirdsthewingsexceededinlengththoseoftherock—pigeon，onanaverage，by11/3inch;whilstinthefivebirdstheywerelessinlengthbyonly。8ofaninch。AsIwasmuchsurprisedthatthewingsofcloselyconfinedbirdsshouldthussofrequentlyhavebeenincreasedinlength，itoccurredtomethatitmightbesolelyduetothegreaterlengthofthewing—feathers;forthiscertainlyisthecasewiththeJacobin，whichhaswingsofunusuallength。AsinalmosteverycaseIhadmeasuredthefoldedwings，Isubtractedthelengthofthisterminalpartfromthatoftheexpandedwings，andthusIobtained，withamoderatedegreeofaccuracy，thelengthofthewingsfromtheendsofthetworadii，answeringfromwristtowristinourarms。Thewings，thusmeasuredinthesametwenty—fivebirds，nowgaveawidelydifferentresult;
fortheywereproportionallywiththoseoftherock—pigeontooshortinseventeenbirds，andinonlyeighttoolong。Oftheseeightbirds，fivewerelong—beaked（5/39。ItperhapsdeservesnoticethatbesidesthesefivebirdstwooftheeightwereBarbs，which，asIhaveshown，mustbeclassedinthesamegroupwiththelong—beakedCarriersandRunts。Barbsmayproperlybecalledshort—beakedCarriers。Itwould，therefore，appearasif，duringthereductionoftheirbeaks，theirwingshadretainedalittleofthatexcessoflengthwhichischaracteristicoftheirnearestrelationsandprogenitors。），andthisfactperhapsindicatesthatthereissomecorrelationofthelengthofthebeakwiththelengthofthebonesofthewings，inthesamemanneraswiththatofthefeetandtarsi。Theshorteningofthehumerusandradiusintheseventeenbirdsmayprobablybeattributedtodisuse，asinthecaseofthescapulaandfurculumtowhichthewing—bonesareattached;——thelengtheningofthewing—feathers，andconsequentlytheexpansionofthewingsfromtiptotip，being，ontheotherhand，ascompletelyindependentofuseanddisuseasisthegrowthofthehairorwoolonourlong—haireddogsorlong—woolledsheep。
Tosumup:wemayconfidentlyadmitthatthelengthofthesternum，andfrequentlytheprominenceofitscrest，thelengthofthescapulaandfurculum，haveallbeenreducedinsizeincomparisonwiththesamepartsintherock—pigeon。AndIpresumethatthismaybeattributedtodisuseorlessenedexercise。Thewings，asmeasuredfromtheendsoftheradii，havelikewisebeengenerallyreducedinlength;but，owingtotheincreasedgrowthofthewing—feathers，thewings，fromtiptotip，arecommonlylongerthanintherock—pigeon。Thefeet，aswellasthetarsiconjointlywiththemiddletoe，havelikewiseinmostcasesbecomereduced;andthisitisprobablehasbeencausedbytheirlesseneduse;buttheexistenceofsomesortofcorrelationbetweenthefeetandbeakisshownmoreplainlythantheeffectsofdisuse。Wehavealsosomefaintindicationofasimilarcorrelationbetweenthemainbonesofthewingandthebeak。
SUMMARYONTHEPOINTSOFDIFFERENCEBETWEENTHESEVERALDOMESTICRACES，AND
BETWEENTHEINDIVIDUALBIRDS。
Thebeak，togetherwiththebonesoftheface，differremarkablyinlength，breadth，shape，andcurvature。Theskulldiffersinshape，andgreatlyintheangleformedbytheunionofthepre—maxillary，nasal，andmaxillo—
jugalbones。Thecurvatureofthelowerjawandthereflectionofitsuppermargin，aswellasthegapeofthemouth，differinahighlyremarkablemanner。Thetonguevariesmuchinlength，bothindependentlyandincorrelationwiththelengthofthebeak。Thedevelopmentofthenaked，wattledskinoverthenostrilsandroundtheeyesvariesinanextremedegree。Theeyelidsandtheexternalorificesofthenostrilsvaryinlength，andaretoacertainextentcorrelatedwiththedegreeofdevelopmentofthewattle。Thesizeandformoftheoesophagusandcrop，andtheircapacityforinflation，differimmensely。Thelengthoftheneckvaries。Withthevaryingshapeofthebody，thebreadthandnumberoftheribs，thepresenceofprocesses，thenumberofthesacralvertebrae，andthelengthofthesternum，allvary。Thenumberandsizeofthecoccygealvertebraevary，apparentlyincorrelationwiththeincreasedsizeofthetail。Thesizeandshapeoftheperforationsinthesternum，andthesizeanddivergenceofthearmsofthefurculum，differ。Theoil—glandvariesindevelopment，andissometimesquiteaborted。Thedirectionandlengthofcertainfeathershavebeenmuchmodified，asinthehoodoftheJacobinandthefrilloftheTurbit。Thewingandtail—feathersgenerallyvaryinlengthtogether，butsometimesindependentlyofeachotherandofthesizeofthebody。Thenumberandpositionofthetail—feathervarytoanunparalleleddegree。Theprimaryandsecondarywing—feathersoccasionallyvaryinnumber，apparentlyincorrelationwiththelengthofthewing。Thelengthofthelegandthesizeofthefeet，and，inconnectionwiththelatter，thenumberofthescutellae，allvary。Awebofskinsometimesconnectsthebasesofthetwoinnertoes，andalmostinvariablythetwooutertoeswhenthefeetarefeathered。
Thesizeofthebodydiffersgreatly:aRunthasbeenknowntoweighmorethanfivetimesasmuchasaShort—facedTumbler。Theeggsdifferinsizeandshape。AccordingtoParmentier（5/40。Temminck’Hist。Nat。Gen。desPigeonsetdesGallinaces’tome11813page170。），someracesusemuchstrawinbuildingtheirnests，andothersuselittle;butIcannothearofanyrecentcorroborationofthisstatement。Thelengthoftimerequiredforhatchingtheeggsisuniforminallthebreeds。Theperiodatwhichthecharacteristicplumageofsomebreedsisacquired，andatwhichcertainchangesofcoloursupervene，differs。Thedegreetowhichtheyoungbirdsareclothedwithdownwhenfirsthatchedisdifferent，andiscorrelatedinasingularmannerwiththecolouroftheplumage。Themannerofflight，andcertaininheritedmovements，suchasclappingthewings，tumblingeitherintheairorontheground，andthemannerofcourtingthefemale，presentthemostsingulardifferences。Indispositiontheseveralracesdiffer。
Someracesareverysilent;otherscooinahighlypeculiarmanner。
Althoughmanydifferentraceshavekepttrueincharacterduringseveralcenturies，asweshallhereaftermorefullysee，yetthereisfarmoreindividualvariabilityinthemostconstantbreedsthaninbirdsinastateofnature。Thereishardlyanyexceptiontotherulethatthosecharactersvarymostwhicharenowmostvaluedandattendedtobyfanciers，andwhichconsequentlyarenowbeingimprovedbycontinuedselection。Thisisindirectlyadmittedbyfancierswhentheycomplainthatitismuchmoredifficulttobreedhighfancypigeonsuptotheproperstandardofexcellencethantheso—calledtoypigeons，whichdifferfromeachothermerelyincolour;forparticularcolourswhenonceacquiredarenotliabletocontinuedimprovementoraugmentation。Somecharactersbecomeattached，fromquiteunknowncauses，morestronglytothemalethantothefemalesex;sothatwehaveincertainraces，atendencytowardstheappearanceofsecondarysexualcharacters（5/41。ThistermwasusedbyJohnHunterforsuchdifferencesinstructurebetweenthemalesandfemales，asarenotdirectlyconnectedwiththeactofreproduction，asthetailofthepeacock，thehornsofdeer，etc。）ofwhichtheaboriginalrock—pigeondisplaysnotatrace。
CHAPTER1。VI。
PIGEONS——continued。
ONTHEABORIGINALPARENT—STOCKOFTHESEVERALDOMESTICRACES。
HABITSOFLIFE。
WILDRACESOFTHEROCK—PIGEON。
DOVECOTE—PIGEONS。
PROOFSOFTHEDESCENTOFTHESEVERALRACESFROMCOLUMBALIVIA。
FERTILITYOFTHERACESWHENCROSSED。
REVERSIONTOTHEPLUMAGEOFTHEWILDROCK—PIGEON。
CIRCUMSTANCESFAVOURABLETOTHEFORMATIONOFTHERACES。
ANTIQUITYANDHISTORYOFTHEPRINCIPALRACES。
MANNEROFTHEIRFORMATION。
SELECTION。
UNCONSCIOUSSELECTION。
CARETAKENBYFANCIERSINSELECTINGTHEIRBIRDS。
SLIGHTLYDIFFERENTSTRAINSGRADUALLYCHANGEINTOWELL—MARKEDBREEDS。
EXTINCTIONOFINTERMEDIATEFORMS。
CERTAINBREEDSREMAINPERMANENT，WHILSTOTHERSCHANGE。
SUMMARY。
Thedifferencesdescribedinthelastchapterbetweentheelevenchiefdomesticracesandbetweenindividualbirdsofthesamerace，wouldbeoflittlesignificance，iftheyhadnotalldescendedfromasinglewildstock。Thequestionoftheiroriginisthereforeoffundamentalimportance，andmustbediscussedatconsiderablelength。Noonewillthinkthissuperfluouswhoconsidersthegreatamountofdifferencebetweentheraces，whoknowshowancientmanyofthemare，andhowtrulytheybreedatthepresentday。Fanciersalmostunanimouslybelievethatthedifferentracesaredescendedfromseveralwildstocks，whereasmostnaturalistsbelievethatallaredescendedfromtheColumbaliviaorrock—pigeon。
Temminck（6/1。Temminck’Hist。Nat。Gen。desPigeons’etc。tome1page191。）haswellobserved，andMr。Gouldhasmadethesameremarktome，thattheaboriginalparentmusthavebeenaspecieswhichroostedandbuiltitsnestonrocks;andImayaddthatitmusthavebeenasocialbird。Forallthedomesticracesarehighlysocial，andnoneareknowntobuildorhabituallytoroostontrees。Theawkwardmannerinwhichsomepigeons，keptbymeinasummer—housenearanoldwalnut—tree，occasionallyalightedonthebarerbranches，wasevident。（6/2。IhaveheardthroughSirC。LyellfromMissBuckley，thatsomehalf—bredCarrierskeptduringmanyyearsnearLondonregularlysettledbydayonsomeadjoiningtrees，and，afterbeingdisturbedintheirloftbytheiryoungbeingtaken，roostedonthematnight。）Nevertheless，Mr。R。ScotSkirvinginformsmethatheoftensawcrowdsofpigeonsinUpperEgyptsettlingonlowtrees，butnotonpalms，inpreferencetoalightingonthemudhovelsofthenatives。InIndiaMr。
Blyth（6/3。’AnnalsandMag。ofNat。Hist。’2ndseriesvolume201857page509;andinalatevolumeofthe’JournaloftheAsiaticSociety。’）hasbeenassuredthatthewildC。livia，var。intermedia，sometimesroostsintrees。Imayheregiveacuriousinstanceofcompulsionleadingtochangedhabits:thebanksoftheNileabovelat。28deg30’areperpendicularforalongdistance，sothatwhentheriverisfullthepigeonscannotalightontheshoretodrink，andMr。Skirvingrepeatedlysawwholeflockssettleonthewater，anddrinkwhilsttheyfloateddownthestream。Theseflocksseenfromadistanceresembledflocksofgullsonthesurfaceofthesea。
Ifanydomesticracehaddescendedfromaspecieswhichwasnotsocial，orwhichbuiltitsnestandroostedintrees（6/4。InworkswrittenonthepigeonbyfanciersIhavesometimesobservedthemistakenbeliefexpressedthatthespecieswhichnaturalistscalledground—pigeons（incontradistinctiontoarborealpigeons）donotperchandbuildontrees。Inthesesameworksbyfancierswildspeciesresemblingthechiefdomesticracesareoftensaidtoexistinvariouspartsoftheworld;butsuchspeciesarequiteunknowntonaturalists。）thesharpeyesoffancierswouldassuredlyhavedetectedsomevestigeofsodifferentanaboriginalhabit。
Forwehavereasontobelievethataboriginalhabitsarelongretainedunderdomestication。Thuswiththecommonassweseesignsofitsoriginaldesertlifeinitsstrongdisliketocrossthesmalleststreamofwater，andinitspleasureinrollinginthedust。Thesamestrongdisliketocrossastreamiscommontothecamel，whichhasbeendomesticatedfromaveryancientperiod。Youngpigs，thoughsotame，sometimessquatwhenfrightened，andthustrytoconcealthemselvesevenonanopenandbareplace。Youngturkeys，andoccasionallyevenyoungfowls，whenthehengivesthedanger—cry，runawayandtrytohidethemselves，likeyoungpartridgesorpheasants，inorderthattheirmothermaytakeflight，ofwhichshehaslostthepower。Themusk—duck（Cairinamoschata）initsnativecountryoftenperchesandroostsontrees（6/5。SirR。Schomburgkin’JournalR。
Geograph。Soc。’volume131844page32。），andourdomesticatedmusk—ducks，thoughsuchsluggishbirds，\"arefondofperchingonthetopsofbarns，walls，etc。，and，ifallowedtospendthenightinthehen—house，thefemalewillgenerallygotoroostbythesideofthehens，butthedrakeistooheavytomountthitherwithease。\"（6/6。Rev。E。S。Dixon’OrnamentalPoultry’1848pages63，66。）Weknowthatthedog，howeverwellandregularlyfed，oftenburies，likethefox，anysuperfluousfood;andweseehimturningroundandroundonacarpet，asiftotrampledowngrasstoformabed;weseehimonbarepavementsscratchingbackwardsasiftothrowearthoverhisexcrement，although，asIbelieve，thisisnevereffectedevenwherethereisearth。Inthedelightwithwhichlambsandkidscrowdtogetherandfriskonthesmallesthillock，weseeavestigeoftheirformeralpinehabits。
Wehavethereforegoodreasontobelievethatallthedomesticracesofthepigeonaredescendedeitherfromsomeoneorfromseveralspecieswhichbothroostedandbuilttheirnestsonrocks，andweresocialindisposition。Asonlyfiveorsixwildspecieshavethesehabits，andmakeanynearapproachinstructuretothedomesticatedpigeon，Iwillenumeratethem。
[Firstly，theColumbaleuconotaresemblescertaindomesticvarietiesinitsplumage，withtheonemarkedandnever—failingdifferenceofawhitebandwhichcrossesthetailatsomedistancefromtheextremity。Thisspecies，moreover，inhabitstheHimalaya，closetothelimitofperpetualsnow;andtherefore，asMr。Blythhasremarked，isnotlikelytohavebeentheparentofourdomesticbreeds，whichthriveinthehottestcountries。Secondly，theC。rupestris，ofCentralAsia，whichisintermediate（6/7。’Proc。
Zoolog。Soc。’1859page400。）betweentheC。leuconotaandlivia;buthasnearlythesamecolouredtailastheformerspecies。Thirdly，theColumbalittoralisbuildsandroosts，accordingtoTemminck，onrocksintheMalayanarchipelago;itiswhite，exceptingpartsofthewingandthetipofthetail，whichareblack;itslegsarelivid—coloured，andthisisacharacternotobservedinanyadultdomesticpigeon;butIneednothavementionedthisspeciesortheclosely—alliedC。luctuosa，astheyinfactbelongtothegenusCarpophaga。Fourthly，Columbaguinea，whichrangesfromGuinea（6/8。Temminck’Hist。Nat。Gen。desPigeons’tome1;also’LesPigeons’parMme。KnipandTemminck。Bonaparte，however，inhis’Coup—
d’oeil’believesthattwocloselyalliedspeciesareconfoundedtogetherunderthisname。TheC。leucocephalaoftheWestIndiesisstatedbyTemmincktobearock—pigeon;butIaminformedbyMr。Gossethatthisisanerror。）totheCapeofGoodHope，androostseitherontreesorrocks，accordingtothenatureofthecountry。ThisspeciesbelongstothegenusStrictoenasofReichenbach，butiscloselyalliedtoColumba;itistosomeextentcolouredlikecertaindomesticraces，andhasbeensaidtobedomesticatedinAbyssinia;butMr。MansfieldParkyns，whocollectedthebirdsofthatcountryandknowsthespecies，informsmethatthisisamistake。Moreover，theC。guineaischaracterisedbythefeathersoftheneckhavingpeculiarnotchedtips，——acharacternotobservedinanydomesticrace。Fifthly，theColumbaoenasofEurope，whichroostsontrees，andbuildsitsnestinholes，eitherintreesortheground;thisspecies，asfarasexternalcharactersgo，mightbetheparentofseveraldomesticraces;but，thoughitcrossesreadilywiththetruerock—pigeon，theoffspring，asweshallpresentlysee，aresterilehybrids，andofsuchsterilitythereisnotatracewhenthedomesticracesareintercrossed。Itshouldalsobeobservedthatifweweretoadmit，againstallprobability，thatanyoftheforegoingfiveorsixspeciesweretheparentsofsomeofourdomesticpigeons，nottheleastlightwouldbethrownonthechiefdifferencesbetweentheelevenmoststrongly—markedraces。
Wenowcometothebestknownrock—pigeon，theColumbalivia，whichisoftendesignatedinEuropepre—eminentlyastheRock—pigeon，andwhichnaturalistsbelievetobetheparentofallthedomesticatedbreeds。Thisbirdagreesineveryessentialcharacterwiththebreedswhichhavebeenonlyslightlymodified。Itdiffersfromallotherspeciesinbeingofaslaty—bluecolour，withtwoblackbarsonthewings，andwiththecroup（orloins）white。OccasionallybirdsareseeninFaroeandtheHebrideswiththeblackbarsreplacedbytwoorthreeblackspots;thisformhasbeennamedbyBrehm（6/9。’HandbuchderNaturgesch。VogelDeutschlands。’）C。
amaliae，butthisspecieshasnotbeenadmittedasdistinctbyotherornithologists。Graba（6/10。’Tagebuch，ReisenachFaro’1830s。62。）evenfoundadifferenceinthebarsontherightandleftwingsofthesamebirdinFaroe。AnotherandrathermoredistinctformiseithertrulywildorhasbecomeferalonthecliffsofEnglandandwasdoubtfullynamedbyMr。Blyth（6/11。’AnnalsandMag。ofNat。Hist。’volume191847page102。Thisexcellentpaperonpigeonsiswellworthconsulting。）asC。affinis，butisnownolongerconsideredbyhimasadistinctspecies。C。affinisisrathersmallerthantherock—pigeonoftheScottishislands，andhasaverydifferentappearanceowingtothewing—covertsbeingchequeredwithblack，withsimilarmarksoftenextendingovertheback。Thechequeringconsistsofalargeblackspotonthetwosides，butchieflyontheouterside，ofeachfeather。Thewing—barsinthetruerock—pigeonandinthechequeredvarietyare，infact，duetosimilarthoughlargerspotssymmetricallycrossingthesecondarywing—featherandthelargercoverts。Hencethechequeringarisesmerelyfromanextensionofthesemarkstootherpartsoftheplumage。ChequeredbirdsarenotconfinedtothecoastsofEngland;fortheywerefoundbyGrabaatFaroe;andW。Thompson（6/12。’NaturalHistoryofIreland’Birdsvolume21850page11。ForGrabaseepreviousreference。）
saysthatatIslayfullyhalfthewildrock—pigeonswerechequered。ColonelKing，ofHythe，stockedhisdovecotewithyoungwildbirdswhichhehimselfprocuredfromnestsattheOrkneyIslands;andseveralspecimens，kindlysenttomebyhim，wereallplainlychequered。Aswethusseethatchequeredbirdsoccurmingledwiththetruerock—pigeonatthreedistinctsites，namely，Faroe，theOrkneyIslands，andIslay，noimportancecanbeattachedtothisnaturalvariationintheplumage。
PrinceC。L。Bonaparte（6/13。’Coup—d’oeilsurl’OrdredesPigeons’’ComptesRendus’1854—55。），agreatdividerofspecies，enumerates，withamarkofinterrogation，asdistinctfromC。livia，theC。turricolaofItaly，theC。
rupestrisofDaouria，andtheC。schimperiofAbyssinia;butthesebirdsdifferfromC。liviaincharactersofthemosttriflingvalue。IntheBritishMuseumthereisachequeredpigeon，probablytheC。schimperiofBonaparte，fromAbyssinia。TothesemaybeaddedtheC。gymnocyclusofG。R。
GrayfromW。Africa，whichisslightlymoredistinct，andhasrathermorenakedskinroundtheeyesthantherock—pigeon;butfrominformationgivenmebyDr。Daniell，itisdoubtfulwhetherthisisawildbird，fordovecote—pigeons（whichIhaveexamined）arekeptonthecoastofGuinea。
Thewildrock—pigeonofIndia（C。intermediaofStrickland）hasbeenmoregenerallyacceptedasadistinctspecies。Itdifferschieflyinthecroupbeingblueinsteadofsnow—white;butasMr。Blythinformsme，thetintvaries，beingsometimesalbescent。Whenthisformisdomesticatedchequeredbirdsappear，justasoccursinEuropewiththetrulywildC。livia。
Moreoverweshallimmediatelyhaveproofthattheblueandwhitecroupisahighlyvariablecharacter;andBechstein（6/14。’NaturgeschichteDeutschlands’b。41795s。14。）assertsthatwithdovecote—pigeonsinGermanythisisthemostvariableofallthecharactersoftheplumage。
HenceitmaybeconcludedthatC。intermediacannotberankedasspecificallydistinctfromC。livia。
InMadeirathereisarock—pigeonwhichafewornithologistshavesuspectedtobedistinctfromC。livia。IhaveexaminednumerousspecimenscollectedbyMr。E。V。HarcourtandMr。Mason。Theyarerathersmallerthantherock—
pigeonfromtheShetlandIslands，andtheirbeaksareplainlythinner，butthethicknessofthebeakvariedintheseveralspecimens。Inplumagethereisremarkablediversity;somespecimensareidenticalineveryfeather（I
speakafteractualcomparison）withtherock—pigeonoftheShetlandIslands;othersarechequered，likeC。affinisfromthecliffsofEngland，butgenerallytoagreaterdegree，beingalmostblackoverthewholeback;
othersareidenticalwiththeso—calledC。intermediaofIndiainthedegreeofbluenessofthecroup;whilstothershavethispartverypaleorverydarkblue，andarelikewisechequered。Somuchvariabilityraisesastrongsuspicionthatthesebirdsaredomesticpigeonswhichhavebecomeferal。
FromthesefactsitcanhardlybedoubtedthatC。livia，affinis，intermedia，andtheformsmarkedwithaninterrogationbyBonaparteoughtalltobeincludedunderasinglespecies。Butitisquiteimmaterialwhetherornottheyarethusranked，andwhethersomeoneoftheseformsorallaretheprogenitorsofthevariousdomestickinds，asfarasanylightcanthusbethrownonthedifferencesbetweenthemorestrongly—markedraces。Thatcommondovecote—pigeons，whicharekeptinvariouspartsoftheworld，aredescendedfromoneorfromseveraloftheabove—mentionedwildvarietiesofC。livia，noonewhocomparesthemwilldoubt。Butbeforemakingafewremarksondovecote—pigeons，itshouldbestatedthatthewildrock—pigeonhasbeenfoundeasytotameinseveralcountries。WehaveseenthatColonelKingatHythestockedhisdovecotemorethantwentyyearsagowithyoungwildbirdstakenattheOrkneyIslands，andsincethentheyhavegreatlymultiplied。TheaccurateMacgillivray（6/15。’HistoryofBritishBirds’volume1pages275—284。Mr。AndrewDuncantamedarock—pigeonintheShetlandIslands。Mr。JamesBarclay，andMr。SmithofUyeaSound，bothsaythatthewildrock—pigeoncanbeeasilytamed;andtheformergentlemanassertsthatthetamedbirdsbreedfourtimesayear。Dr。LawrenceEdmondstoneinformsmethatawildrock—pigeoncameandsettledinhisdovecoteinBaltaSoundintheShetlandIslands，andbredwithhispigeons;
hehasalsogivenmeotherinstancesofthewildrock—pigeonhavingbeentakenyoungandbreedingincaptivity。）assertsthathecompletelytamedawildrock—pigeonintheHebrides;andseveralaccountsareonrecordsofthesepigeonshavingbredindovecotesintheShetlandIslands。InIndia，asCaptainHuttoninformsme，thewildrock—pigeoniseasilytamed，andbreedsreadilywiththedomestickind;andMr。Blyth（6/16。’AnnalsandMag。ofNat。History’volume191847page103andvolumefor1857page512。）assertsthatwildbirdscomefrequentlytothedovecotesandminglefreelywiththeirinhabitants。Intheancient’AyeenAkbery’itiswrittenthat，ifafewwildpigeonsbetaken，\"theyarespeedilyjoinedbyathousandothersoftheirkind。\"
Dovecote—pigeonsarethosewhicharekeptindovecotesinasemi—