domesticatedstate;fornospecialcareistakenofthem，andtheyprocuretheirownfood，exceptduringtheseverestweather。InEngland，and，judgingfromMM。BoitardandCorbie’swork，inFrance，thecommondovecote—
pigeonexactlyresemblesthechequeredvarietyofC。livia;butIhaveseendovecotesbroughtfromYorkshirewithoutanytraceofchequering，likethewildrock—pigeonoftheShetlandIslands。ThechequereddovecotesfromtheOrkneyIslands，afterhavingbeendomesticatedbyColonelKingformorethantwentyyears，differedslightlyfromeachotherinthedarknessoftheirplumageandinthethicknessoftheirbeaks;thethinnestbeakbeingratherthickerthanthethickestoneintheMadeirabirds。InGermany，accordingtoBechstein，thecommondovecote—pigeonisnotchequered。InIndiatheyoftenbecomechequered，andsometimespiedwithwhite;thecroupalso，asIaminformedbyMr。Blyth，becomesnearlywhite。IhavereceivedfromSir。J。Brookesomedovecote—pigeons，whichoriginallycamefromtheS。NatunasIslandsintheMalayArchipelago，andwhichhadbeencrossedwiththeSingaporedovecotes:theyweresmallandthedarkestvarietywasextremelylikethedarkchequeredvarietywithabluecroupfromMadeira;
butthebeakwasnotsothin，thoughdecidedlythinnerthanintherock—
pigeonfromtheShetlandIslands。Adovecote—pigeonsenttomebyMr。
SwinhoefromFoochow，inChina，waslikewiserathersmall，butdifferedinnootherrespect。IhavealsoreceivedthroughthekindnessofDr。Daniell，fourlivingdovecote—pigeonsfromSierraLeone（6/17。DomesticpigeonsofthecommonkindarementionedasbeingprettynumerousinJohnBarbut’s’DescriptionoftheCoastofGuinea’page215publishedin1746;theyaresaid，inaccordancewiththenamewhichtheybear，tohavebeenimported。）
thesewerefullyaslargeastheShetlandrock—pigeon，withevenbulkierbodies。InplumagesomeofthemwereidenticalwiththeShetlandrockpigeon，butwiththemetallictintsapparentlyrathermorebrilliant;
othershadabluecroup，andresembledthechequeredvarietyofC。
intermediaofIndia;andsomeweresomuchchequeredastobenearlyblack。
Inthesefourbirdsthebeakdifferedslightlyinlength，butinallitwasdecidedlyshorter，moremassive，andstrongerthaninthewildrock—pigeonfromtheShetlandIslands，orintheEnglishdovecote。WhenthebeaksoftheseAfricanpigeonswerecomparedwiththethinnestbeaksofthewildMadeiraspecimens，thecontrastwasgreat;theformerbeingfullyone—thirdthickerinaverticaldirectionthanthelatter;sothatanyoneatfirstwouldhavefeltinclinedtorankthesebirdsasspecificallydistinct;yetsoperfectlygraduatedaseriescouldbeformedbetweentheabove—mentionedvarieties，thatitwasobviouslyimpossibletoseparatethem。]
Tosumup:thewildColumbalivia，includingunderthisnameC。affinis，intermedia，andtheotherstillmoreclosely—affinedgeographicalraces，hasavastrangefromthesoutherncoastofNorwayandtheFaroeIslandstotheshoresoftheMediterranean，toMadeiraandtheCanaryIslands，toAbyssinia，India，andJapan。Itvariesgreatlyinplumage，beinginmanyplaceschequeredwithblack，andhavingeitherawhiteorbluecrouporloins;itvariesalsoslightlyinthesizeofthebeakandbody。Dovecote—
pigeons，whichnoonedisputesaredescendedfromoneormoreoftheabovewildforms，presentasimilarbutgreaterrangeofvariationinplumage，inthesizeofbody，andinthelengthandthicknessofthebeak。Thereseemstobesomerelationbetweenthecroupbeingblueorwhite，andthetemperatureofthecountryinhabitedbybothwildanddovecotepigeons;fornearlyallthedovecote—pigeonsinthenorthernpartsofEuropehaveawhitecroup，likethatofthewildEuropeanrock—pigeon;andnearlyallthedovecote—pigeonsofIndiahaveabluecrouplikethatofthewildC。
intermediaofIndia。Asinvariouscountriesthewildrock—pigeonhasbeenfoundeasytotame，itseemsextremelyprobablethatthedovecote—pigeonsthroughouttheworldarethedescendantsofatleasttwoandperhapsmorewildstocks;butthese，aswehavejustseen，cannotberankedasspecificallydistinct。
WithrespecttothevariationofC。livia，wemaywithoutfearofcontradictiongoonestepfurther。Thosepigeon—fancierswhobelievethatallthechiefraces，suchasCarriers，Pouters，Fantails，etc。，aredescendedfromdistinctaboriginalstocks，yetadmitthattheso—calledtoy—pigeons，whichdifferfromtherock—pigeoninlittleexceptcolour，aredescendedfromthisbird。Bytoy—pigeonsaremeantsuchbirdsasSpots，Nuns，Helmets，Swallows，Priests，Monks，Porcelains，Swabians，Archangels，Breasts，Shields，andothersinEurope，andmanyothersinIndia。Itwouldindeedbeaspueriletosupposethatallthesebirdsaredescendedfromsomanydistinctwildstocksastosupposethistobethecasewiththemanyvarietiesofthegooseberry，heartsease，ordahlia。Yetthesekindsallbreedtrue，andmanyofthemincludesub—varietieswhichlikewisetransmittheircharactertruly。Theydiffergreatlyfromeachotherandfromtherock—pigeoninplumage，slightlyinsizeandproportionsofbody，insizeoffeet，andinthelengthandthicknessoftheirbeaks。Theydifferfromeachotherintheserespectsmorethandodovecote—pigeons。Althoughwemaysafelyadmitthatdovecote—pigeons，whichvaryslightly，andthattoy—
pigeons，whichvaryinagreaterdegreeinaccordancewiththeirmorehighly—domesticatedcondition，aredescendedfromC。livia，includingunderthisnametheabove—enumeratedwildgeographicalraces;yetthequestionbecomesfarmoredifficultwhenweconsidertheelevenprincipalraces，mostofwhichhavebeenprofoundlymodified。Itcan，however，beshown，byindirectevidenceofaperfectlyconclusivenature，thattheseprincipalracesarenotdescendedfromsomanywildstocks;andifthisbeonceadmitted，fewwilldisputethattheyarethedescendantsofC。livia，whichagreeswiththemsocloselyinhabitsandinmostcharacters，whichvariesinastateofnature，andwhichhascertainlyundergoneaconsiderableamountofvariation，asinthetoy—pigeons。Weshallmoreoverpresentlyseehoweminentlyfavourablecircumstanceshavebeenforagreatamountofmodificationinthemorecarefullytendedbreeds。
Thereasonsforconcludingthattheseveralprincipalracesarenotdescendedfromsomanyaboriginalandunknownstocksmaybegroupedunderthefollowingsixheads:——
FIRSTLY。
Iftheelevenchiefraceshavenotarisenfromthevariationofsomeonespecies，togetherwithitsgeographicalraces，theymustbedescendedfromseveralextremelydistinctaboriginalspecies;fornoamountofcrossingbetweenonlysixorsevenwildformscouldproduceracessodistinctasPouters，Carriers，Runts，Fantails，Turbits，Short—facedTumblers，Jacobins，andTrumpeters。Howcouldcrossingproduce，forinstance，aPouteroraFantail，unlessthetwosupposedaboriginalparentspossessedtheremarkablecharactersofthesebreeds？Iamawarethatsomenaturalists，followingPallas，believethatcrossinggivesastrongtendencytovariation，independentlyofthecharactersinheritedfromeitherparent。TheybelievethatitwouldbeeasiertoraiseaPouterorFantailpigeonfromcrossingtwodistinctspecies，neitherofwhichpossessedthecharactersoftheseraces，thanfromanysinglespecies。I
canfindfewfactsinsupportofthisdoctrine，andbelieveinitonlytoalimiteddegree;butinafuturechapterIshallhavetorecurtothissubject。Forourpresentpurposethepointisnotmaterial。Thequestionwhichconcernsusis，whetherornotmanynewandimportantcharactershavearisensincemanfirstdomesticatedthepigeon。Ontheordinaryview，variabilityisduetochangedconditionsoflife;onthePallasiandoctrine，variability，ortheappearanceofnewcharacters，isduetosomemysteriouseffectfromthecrossingoftwospecies，neitherofwhichpossessesthecharactersinquestion。Insomefewinstancesitispossiblethatwell—markedracesmayhavebeenformedbycrossing;forinstance，aBarbmightperhapsbeformedbyacrossbetweenalong—beakedCarrier，havinglargeeye—wattles，andsomeshort—beakedpigeon。Thatmanyraceshavebeeninsomedegreemodifiedbycrossing，andthatcertainvarietieswhicharedistinguishedonlybypeculiartintshavearisenfromcrossesbetweendifferently—colouredvarieties，isalmostcertain。Onthedoctrine，therefore，thatthechiefracesowetheirdifferencestotheirdescentfromdistinctspecies，wemustadmitthatatleasteightornine，ormoreprobablyadozenspecies，allhavingthesamehabitofbreedingandroostingonrocksandlivinginsociety，eithernowexistsomewhere，orformerlyexisted，buthavebecomeextinctaswildbirds。Consideringhowcarefullywildpigeonshavebeencollectedthroughouttheworld，andwhatconspicuousbirdstheyare，especiallywhenfrequentingrocks，itisextremelyimprobablethateightorninespecies，whichwerelongagodomesticatedandthereforemusthaveinhabitedsomeancientlyknowncountry，shouldstillexistinthewildstateandbeunknowntoornithologists。
Thehypothesisthatsuchspeciesformerlyexisted，buthavebecomeextinct，isinsomeslightdegreemoreprobable。Buttheextinctionofsomanyspecieswithinthehistoricalperiodisaboldhypothesis，seeinghowlittleinfluencemanhashadinexterminatingthecommonrock—pigeon，whichagreesinallitshabitsoflifewiththedomesticraces。TheC。livianowexistsandflourishesonthesmallnorthernislandsofFaroe，onmanyislandsoffthecoastofScotland，onSardinia，andtheshoresoftheMediterranean，andinthecentreofIndia。Fanciershavesometimesimaginedthattheseveralsupposedparent—specieswereoriginallyconfinedtosmallislands，andthusmightreadilyhavebeenexterminated;butthefactsjustgivendonotfavourtheprobabilityoftheirextinction，evenonsmallislands。Norisitprobable，fromwhatisknownofthedistributionofbirds，thattheislandsnearEuropeshouldhavebeeninhabitedbypeculiarspeciesofpigeons;andifweassumethatdistantoceanicislandswerethehomesofthesupposedparent—species，wemustrememberthatancientvoyagesweretediouslyslow，andthatshipswerethenill—providedwithfreshfood，sothatitwouldnothavebeeneasytobringhomelivingbirds。Ihavesaidancientvoyages，fornearlyalltheracesofthepigeonwereknownbeforetheyear1600，sothatthesupposedwildspeciesmusthavebeencapturedanddomesticatedbeforethatdate。
SECONDLY。
Thedoctrinethatthechiefdomesticracesaredescendedfromseveralaboriginalspecies，impliesthatseveralspecieswereformerlysothoroughlydomesticatedastobreedreadilywhenconfined。Althoughitiseasytotamemostwildbirds，experienceshowsusthatitisdifficulttogetthemtobreedfreelyunderconfinement;althoughitmustbeownedthatthisislessdifficultwithpigeonsthanwithmostotherbirds。Duringthelasttwoorthreehundredyears，manybirdshavebeenkeptinaviaries，buthardlyonehasbeenaddedtoourlistofthoroughlyreclaimedspecies:yetontheabovedoctrinewemustadmitthatinancienttimesnearlyadozenkindsofpigeons，nowunknowninthewildstate，werethoroughlydomesticated。
THIRDLY。
Mostofourdomesticatedanimalshaverunwildinvariouspartsoftheworld;butbirds，owingapparentlytotheirpartiallossofthepowerofflight，lessoftenthanquadrupeds。NeverthelessIhavemetwithaccountsshowingthatthecommonfowlhasbecomeferalinSouthAmericaandperhapsinWestAfrica，andonseveralislands:theturkeywasatonetimealmostferalonthebanksoftheParana;andtheGuinea—fowlhasbecomeperfectlywildatAscensionandinJamaica。Inthislatterislandthepeacock，also，\"hasbecomeamaroonbird。\"ThecommonduckwandersfromitshomeandbecomesalmostwildinNorfolk。Hybridsbetweenthecommonandmusk—duckwhichhavebecomewildhavebeenshotinNorthAmerica，Belgium，andneartheCaspianSea。ThegooseissaidtohaverunwildinLaPlata。Thecommondovecote—pigeonhasbecomewildatJuanFernandez，NorfolkIsland，Ascension，probablyatMadeira，ontheshoresofScotland，and，asisasserted，onthebanksoftheHudsoninNorthAmerica。（6/18。Withrespecttoferalpigeons——forJuanFernandezseeBerteroin’Annal。desSc。Nat。’
tome21page351。ForNorfolkIslandsseeRev。E。S。Dixoninthe’Dovecote’
1851page14ontheauthorityofMr。Gould。ForAscensionIrelyonMS。
informationgivenmebyMr。Layard。ForthebanksoftheHudson，seeBlythin’AnnalsofNat。Hist。’volume201857page511。ForScotlandseeMacgillivray’BritishBirds’volume1page275;alsoThompson’Nat。Hist。
ofIreland，Birds’volume2page11。ForducksseeRev。E。S。Dixon’OrnamentalPoultry’1847page122。Fortheferalhybridsofthecommonandmusk—ducksseeAudubon’AmericanOrnithology’andSelys—Longchamp’HybridesdanslaFamilledesAnatides。’ForthegooseIsidoreGeoffroySt。—Hilaire’Hist。Nat。Gen。’tome3page498。Forguinea—fowlsseeGosse’Naturalist’sSojourninJamaica’page124;andhis’BirdsofJamaica’forfullerparticulars。Isawthewildguinea—fowlinAscension。Forthepeacocksee’AWeekatPortRoyal’byacompetentauthority，Mr。R。Hill，page42。FortheturkeyIrelyonoralinformation;IascertainedthattheywerenotCurassows。WithrespecttofowlsIwillgivethereferencesinthenextchapter。）Buthowdifferentisthecase，whenweturntotheelevenchiefdomesticracesofthepigeon，whicharesupposedbysomeauthorstobedescendedfromsomanydistinctspecies！noonehaseverpretendedthatanyoneoftheseraceshasbeenfoundwildinanyquarteroftheworld;yettheyhavebeentransportedtoallcountries，andsomeofthemmusthavebeencarriedbacktotheirnativehomes。Ontheviewthatalltheracesaretheproductofvariation，wecanunderstandwhytheyhavenotbecomeferal，forthegreatamountofmodificationwhichtheyhaveundergoneshowshowlongandhowthoroughlytheyhavebeendomesticated;andthiswouldunfitthemforawildlife。
FOURTHLY。
Ifitbeassumedthatthecharacteristicdifferencesbetweenthevariousdomesticracesareduetodescentfromseveralaboriginalspecies，wemustconcludethatmanchosefordomesticationinancienttimes，eitherintentionallyorbychance，amostabnormalsetofpigeons;forthatspeciesresemblingsuchbirdsasPouters，Fantails，Carriers，Barbs，Short—
facedTumblers，Turbits，etc。，wouldbeinthehighestdegreeabnormal，ascomparedwithalltheexistingmembersofthegreatpigeonfamily，cannotbedoubted。Thusweshouldhavetobelievethatmannotonlyformerlysucceededinthoroughlydomesticatingseveralhighlyabnormalspecies，butthatthesesamespecieshavesinceallbecomeextinct，orareatleastnowunknown。Thisdoubleaccidentissoextremelyimprobablethattheassumedexistenceofsomanyabnormalspecieswouldrequiretobesupportedbythestrongestevidence。Ontheotherhand，ifalltheracesaredescendedfromC。livia，wecanunderstand，aswillhereafterbemorefullyexplained，howanyslightdeviationinstructurewhichfirstappearedwouldcontinuallybeaugmentedbythepreservationofthemoststronglymarkedindividuals;andasthepowerofselectionwouldbeappliedaccordingtoman’sfancy，andnotforthebird’sowngood，theaccumulatedamountofdeviationwouldcertainlybeofanabnormalnatureincomparisonwiththestructureofpigeonslivinginastateofnature。
Ihavealreadyalludedtotheremarkablefactthatthecharacteristicdifferencesbetweenthechiefdomesticracesareeminentlyvariable;weseethisplainlyinthegreatdifferenceinthenumberofthetail—feathersintheFantail，inthedevelopmentofthecropinPouters，inthelengthofthebeakinTumblers，inthestateofthewattleinCarriers，etc。Ifthesecharactersaretheresultofsuccessivevariationsaddedtogetherbyselection，wecanunderstandwhytheyshouldbesovariable:forthesearetheverypartswhichhavevariedsincethedomesticationofthepigeon，andthereforewouldbelikelystilltovary;thesevariationsmoreoverhavebeenrecently，andarestillbeingaccumulatedbyman’sselection;
thereforetheyhavenotasyetbecomefirmlyfixed。
FIFTHLY。
Allthedomesticracespairreadilytogether，and，whatisequallyimportant，theirmongreloffspringareperfectlyfertile。ToascertainthisfactImademanyexperiments，whicharegiveninthenotebelow;andrecentlyMr。Tegetmeierhasmadesimilarexperimentswiththesameresult。
（6/19。IhavedrawnoutalongtableofthevariouscrossesmadebyfanciersbetweentheseveraldomesticbreedsbutIdonotthinkitworthwhilepublishing。Ihavemyselfmadeforthisspecialpurposemanycrosses，andallwereperfectlyfertile。Ihaveunitedinonebirdfiveofthemostdistinctraces，andwithpatienceImightundoubtedlyhavethusunitedall。
Thecaseoffivedistinctbreedsbeingblendedtogetherwithunimpairedfertilityisimportant，becauseGartnerhasshownthatitisaverygeneral，thoughnot，ashethought，universalrule，thatcomplexcrossesbetweenseveralspeciesareexcessivelysterile。Ihavemetwithonlytwoorthreecasesofreportedsterilityintheoffspringofcertainraceswhencrossed。Pistor（’DasGanzederFeldtaubenzucht’1831s。15）assertsthatthemongrelsfromBarbsandFantailsaresterile:Ihaveprovedthistobeerroneous，notonlybycrossingthosehybridswithseveralotherhybridsofthesameparentage，butbythemoreseveretestofpairingbrotherandsisterhybridsinterse，andtheywerePERFECTLYfertile。Temminckhasstated（’Hist。Nat。Gen。desPigeons’tome1page197）thattheTurbitorOwlwillnotcrossreadilywithotherbreeds:butmyTurbitscrossed，whenleftfreewithAlmondTumblersandwithTrumpeters;thesamethinghasoccurred（Rev。E。S。Dixon’TheDovecote’page107）betweenTurbitsandDovecotesandNuns。IhavecrossedTurbitswithBarbs，ashasM。Boitard（page34），whosaysthehybridswereveryfertile。HybridsfromaTurbitandFantailhavebeenknowntobreedinterse（Riedel’Taubenzucht’s。25
andBechstein’Naturgesch。Deutsch。’b。4s。44。Turbits（Riedels。26）
havebeencrossedwithPoutersandwithJacobins，andwithahybridJacobin—trumpeter（Riedels。27）。Thelatterauthorhas，however，madesomevaguestatements（s。22）onthesterilityofTurbitswhencrossedwithcertainothercrossedbreeds。ButIhavelittledoubtthattheRev。E。S。
Dixon’sexplanationofsuchstatementsiscorrect，viz。thatindividualbirdsbothwithTurbitsandotherbreedsareoccasionallysterile。）TheaccurateNeumeisterassertsthatwhendovecotesarecrossedwithpigeonsofanyotherbreed，themongrelsareextremelyfertileandhardy。（6/20。’DasGanzederTaubenzucht’s。18。）MM。BoitardandCorbie（6/21。’LesPigeons’
etc。page35。）affirm，aftertheirgreatexperience，thatthemoredistinctthebreedsarewhicharecrossed，themoreproductivearetheirmongreloffspring。IadmitthatthedoctrinefirstbroachedbyPallasishighlyprobable，ifnotactuallyproved，namely，thatcloselyalliedspecies，whichinastateofnatureorwhenfirstcapturedwouldhavebeeninsomedegreesterileifcrossed，losethissterilityafteralongcourseofdomestication;yetwhenweconsiderthegreatdifferencebetweensuchracesasPouters，Carriers，Runts，Fantails，Turbits，Tumblersetc。，thefactoftheirperfect，orevenincreased，fertilitywhenintercrossedinthemostcomplicatedmannerbecomesastrongargumentinfavouroftheirhavingalldescendedfromasinglespecies。Thisargumentisrenderedmuchstrongerwhenwehear（Iappendinanote（6/22。DomesticpigeonspairreadilywiththealliedC。oenas（Bechstein’Naturgesch。Deutschlands’b。4s。3）;andMr。BrenthasmadethesamecrossseveraltimesinEngland，buttheyoungwereveryapttodieatabouttendaysold;onehybridwhichhereared（fromC。oenasandamaleAntwerpCarrier）pairedwithaDragon，butneverlaideggs。Bechsteinfurtherstates（s。26）thatthedomesticpigeonwillcrosswithC。palumbus，TurturrisoriaandT。vulgaris，butnothingissaidofthefertilityofthehybrids，andthiswouldhavebeenmentionedhadthefactbeenascertained。IntheZoologicalGardens（MS。reporttomefromMr。
JamesHunt）amalehybridfromTurturvulgarisandadomesticpigeon\"pairedwithseveraldifferentspeciesofpigeonsanddoves，butnoneoftheeggsweregood。\"HybridsfromC。oenasandgymnophthalmosweresterile。
InLoudon’s’Mag。ofNat。Hist。’volume71834page154itissaidthatamalehybrid（fromTurturvulgarismale，andthecream—colouredT。risoriafemale）pairedduringtwoyearswithafemaleT。risoria，andthelatterlaidmanyeggs，butallweresterile。MM。BoitardandCorbie（’LesPigeons’
page235）statethatthehybridsfromthesetwoturtle—dovesareinvariablysterilebothinterseandwitheitherpureparent。TheexperimentwastriedbyM。Corbie\"avecuneespeced’obstination;\"andlikewisebyM。Mauduyt，andbyM。Vieillot。Temminckalsofoundthehybridsfromthesetwospeciesquitebarren。Therefore，whenBechstein（’Naturgesch。DeutschlandsVogel’
b。4s。101）assertsthatthehybridsfromthesetwoturtle—dovespropagateinterseequallywellwithpurespecies，andwhenawriterinthe’Field’
newspaper（inaletterdatedNovember10th，1858）makesasimilarassertion，itwouldappearthattheremustbesomemistake;thoughwhatthemistakeisIknownot，asBechsteinatleastmusthaveknownthewhitevarietyofT。risoria:itwouldbeanunparalleledfactifthesametwospeciessometimesproducedEXTREMELYfertile，andsometimesEXTREMELY
barren，offspring。IntheMS。reportfromtheZoologicalGardensitissaidthathybridsfromTurturvulgarisandsuratensis，andfromT。vulgarisandEctopistesmigratorius，weresterile。Twoofthelattermalehybridspairedwiththeirpureparents，viz。TurturvulgarisandtheEctopistes，andlikewisewithT。risoriaandwithColumbaoenas，andmanyeggswereproduced，butallwerebarren。AtParis，hybridshavebeenraised（Isid。
GeoffreySaint—Hilaire’Hist。Nat。Generale’tome3page180）fromTurturaurituswithT。cambayensisandwithT。suratensis;butnothingissaidoftheirfertility。AttheZoologicalGardensofLondontheGouracoronataandvictoriaeproducedahybridwhichpairedwiththepureG。coronata，andlaidseveraleggs，buttheseprovedbarren。In1860Columbagymnophthalmosandmaculosaproducedhybridsinthesesamegardens。）allthecaseswhichI
havecollected）thathardlyasinglewell—ascertainedinstanceisknownofhybridsbetweentwotruespeciesofpigeonsbeingfertile，interse，orevenwhencrossedwithoneoftheirpureparents。
SIXTHLY。
Excludingcertainimportantcharacteristicdifferences，thechiefracesagreemostcloselybothwitheachotherandwithC。liviainallotherrespects。Aspreviouslyobserved，allareeminentlysociable;alldisliketoperchorroost，andrefusetobuildintrees;alllaytwoeggs，andthisisnotauniversalrulewiththeColumbidae;all，asfarasIcanhear，requirethesametimeforhatchingtheireggs;allcanendurethesamegreatrangeofclimate;allpreferthesamefood，andarepassionatelyfondofsalt;allexhibit（withtheassertedexceptionoftheFinnikinandTurnerwhichdonotdiffermuchinanyothercharacter）thesamepeculiargestureswhencourtingthefemales;andall（withtheexceptionofTrumpetersandLaughers，whichlikewisedonotdiffermuchinanyothercharacter）coointhesamepeculiarmanner，unlikethevoiceofanyotherwildpigeon。Allthecolouredbreedsdisplaythesamepeculiarmetallictintsonthebreast，acharacterfarfromgeneralwithpigeons。Eachracepresentsnearlythesamerangeofvariationincolour;andinmostoftheraceswehavethesamesingularcorrelationbetweenthedevelopmentofdownintheyoungandthefuturecolourofplumage。Allhavetheproportionallengthoftheirtoes，andoftheirprimarywing—feathers，nearlythesame，—
—characterswhichareapttodifferintheseveralmembersoftheColumbidae。Inthoseraceswhichpresentsomeremarkabledeviationofstructure，suchasinthetailofFantails，cropofPouters，beakofCarriersandTumblers，etc。，theotherpartsremainnearlyunaltered。Noweverynaturalistwilladmitthatitwouldbescarcelypossibletopickoutadozennaturalspeciesinanyfamilywhichshouldagreecloselyinhabitsandingeneralstructure，andyetshoulddiffergreatlyinafewcharactersalone。Thisfactisexplicablethroughthedoctrineofnaturalselection;
foreachsuccessivemodificationofstructureineachnaturalspeciesispreserved，solelybecauseitisofservice;andsuchmodificationswhenlargelyaccumulatedimplyagreatchangeinthehabitsoflife，andthiswillalmostcertainlyleadtootherchangesofstructurethroughoutthewholeorganisation。Ontheotherhand，iftheseveralracesofthepigeonhavebeenproducedbymanthroughselectionandvariation，wecanreadilyunderstandhowitisthattheyshouldstillallresembleeachotherinhabitsandinthosemanycharacterswhichmanhasnotcaredtomodify，whilsttheydiffertosoprodigiousadegreeinthosepartswhichhavestruckhiseyeorpleasedhisfancy。
Besidesthepointsaboveenumerated，inwhichallthedomesticracesresembleC。liviaandeachother，thereisonewhichdeservesspecialnotice。Thewildrock—pigeonisofaslaty—bluecolour;thewingsarecrossedbytwobars;thecroupvariesincolour，beinggenerallywhiteinthepigeonofEurope，andblueinthatofIndia;thetailhasablackbarclosetotheend，andtheouterwebsoftheoutertail—feathersareedgedwithwhite，exceptnearthetips。ThesecombinedcharactersarenotfoundinanywildpigeonbesidesC。livia。IhavelookedcarefullythroughthegreatcollectionsofpigeonsintheBritishMuseum，andIfindthatadarkbarattheendofthetailiscommon;thatthewhiteedgingtotheoutertail—feathersisnotrare;butthatthewhitecroupisextremelyrare，andthetwoblackbarsonthewingsoccurinnootherpigeon，exceptingthealpineC。leuconotaandC。rupestrisofAsia。Nowifweturntothedomesticraces，itishighlyremarkable，asaneminentfancier，Mr。
Wicking，observedtome，that，wheneverabluebirdappearsinanyrace，thewingsalmostinvariablyshowthedoubleblackbars。（6/23。Thereisoneexceptiontotherule，namely，inasub—varietyoftheSwallowofGermanorigin，whichisfiguredbyNeumeister，andwasshowntomebyMr。Wicking。
Thisbirdisblue，buthasnottheblackwing—bars;forourobject，however，intracingthedescentofthechiefraces，thisexceptionsignifiesthelessastheSwallowapproachescloselyinstructuretoC。
livia。Inmanysub—varietiestheblackbarsarereplacedbybarsofvariouscolours。ThefiguresgivenbyNeumeisteraresufficienttoshowthat，ifthewingsaloneareblue，theblackwing—barsappear。）Theprimarywing—
feathersmaybewhiteorblack，andthewholebodymaybeofanycolour，butifthewing—covertsareblue，thetwoblackbarsaresuretoappear。I
havemyselfseen，oracquiredtrustworthyevidence，asgivenbelow（6/24。I
haveobservedbluebirdswithalltheabove—mentionedmarksinthefollowingraces，whichseemedtobeperfectlypure，andwereshownatvariousexhibitions。Pouters，withthedoubleblackwing—bars，withwhitecroup，darkbartoendoftail，andwhiteedgingtooutertail—feathers。
Turbits，withallthesesamecharacters。Fantailswiththesame;butthecroupinsomewasbluishorpureblue。Mr。WickingbredblueFantailsfromtwoblackbirds。Carriers（includingtheBagadottenofNeumeister）withallthemarks:twobirdswhichIexaminedhadwhite，andtwohadbluecroups;
thewhiteedgingtotheoutertail—featherswasnotpresentinall。Mr。
Corker，agreatbreeder，assuresmethat，ifblackcarriersarematchedformanysuccessivegenerations，theoffspringbecomefirstash—coloured，andthenbluewithblackwing—bars。Runtsoftheelongatedbreedhadthesamemarks，butthecroupwaspaleblue;theoutertail—feathershadwhiteedges。NeumeisterfiguresthegreatFlorenceRuntofabluecolourwithblackbars。Jacobinsareveryrarelyblue，butIhavereceivedauthenticaccountsofatleasttwoinstancesofthebluevarietywithblackbarshavingappearedinEngland;blueJacobinswerebredbyMr。Brentfromtwoblackbirds。IhaveseencommonTumblers，bothIndianandEnglish，andShort—facedTumblers，ofabluecolour，withblackwing—bars，withtheblackbarattheendofthetail，andwiththeoutertail—feathersedgedwithwhite;thecroupinallwasblue，orextremelypaleblue，neverabsolutelywhite。BlueBarbsandTrumpetersseemtobeexcessivelyrare;
butNeumeister，whomaybeimplicitlytrusted，figuresbluevarietiesofboth，withblackwing—bars。Mr。BrentinformsmethathehasseenablueBarb;andMr。H。Weir，asIaminformedbyMr。Tegetmeier，oncebredasilver（whichmeansverypaleblue）Barbfromtwoyellowbirds。），ofbluebirdswithblackbarsonthewing，withthecroupeitherwhiteorverypaleordarkblue，withthetailhavingaterminalblackbar，andwiththeouterfeathersexternallyedgedwithwhiteorverypalecoloured，inthefollowingraces，which，asIcarefullyobservedineachcase，appearedtobeperfectlytrue:namely，inPouters，Fantails，Tumblers，Jacobins，Turbits，Barbs，Carriers，Runtsofthreedistinctvarieties，Trumpeters，Swallows，andinmanyothertoy—pigeons，whichasbeingcloselyalliedtoC。livia，arenotworthenumerating。Thusweseethat，inpurely—bredracesofeverykindknowninEurope，bluebirdsoccasionallyappearhavingallthemarkswhichcharacteriseC。livia，andwhichconcurinnootherwildspecies。Mr。Blyth，also，hasmadethesameobservationwithrespecttothevariousdomesticracesknowninIndia。
CertainvariationsintheplumageareequallycommoninthewildC。livia，indovecote—pigeons，andinallthemosthighlymodifiedraces。Thus，inall，thecroupvariesfromwhitetoblue，beingmostfrequentlywhiteinEurope，andverygenerallyblueinIndia。（6/25。Mr。BlythinformsmethatallthedomesticracesinIndiahavethecroupblue;butthisisnotinvariable，forIpossessaverypaleblueSimmalipigeonwiththecroupperfectlywhite，senttomebySirW。ElliotfromMadras。Aslaty—blueandchequeredNakshipigeonhassomewhitefeathersonthecroupalone。InsomeotherIndianpigeonstherewereafewwhitefeathersconfinedtothecroup，andIhavenoticedthesamefactinacarrierfromPersia。TheJavaFantail（importedintoAmoy，andthencesentme）hasaperfectlywhitecroup。）WehaveseenthatthewildC。liviainEurope，anddovecotesinallpartsoftheworld，oftenhavetheupperwing—covertschequeredwithblack;andallthemostdistinctraces，whenblue，areoccasionallychequeredinpreciselythesamemanner。ThusIhaveseenPouters，Fantails，Carriers，Turbits，Tumblers（IndianandEnglish），Swallows，Bald—pates，andothertoy—pigeonsblueandchequered;andMr。EsquilanthasseenachequeredRunt。IbredfromtwopureblueTumblersachequeredbird。
Thefactshithertogivenrefertotheoccasionalappearanceinpureracesofbluebirdswithblackwing—bars，andlikewiseofblueandchequeredbirds;butitwillnowbeseenthatwhentwobirdsbelongingtodistinctracesarecrossed，neitherofwhichhave，norprobablyhavehadduringmanygenerations，atraceofblueintheirplumage，oratraceofwing—barsandtheothercharacteristicmarks，theyveryfrequentlyproducemongreloffspringofabluecolour，sometimeschequered，withblackwing—bars，etc。;orifnotofabluecolour，yetwiththeseveralcharacteristicmarksmoreorlessplainlydeveloped。IwasledtoinvestigatethissubjectfromMM。BoitardandCorbie（6/26。’LesPigeons’etc。page37。）havingassertedthatfromcrossesbetweencertainbreedsitisraretogetanythingbutbisetsordovecotepigeons，which，asweknow，arebluebirdswiththeusualcharacteristicmarks。Weshallhereafterseethatthissubjectpossesses，independentlyofourpresentobject，considerableinterest，sothatIwillgivetheresultsofmyowntrialsinfull。Iselectedforexperimentraceswhich，whenpure，veryseldomproducebirdsofabluecolour，orhavebarsontheirwingsandtail。
TheNuniswhite，withthehead，tail，andprimarywing—feathersblack;itisabreedwhichwasestablishedaslongagoastheyear1600。IcrossedamaleNunwithafemaleredcommonTumbler，whichlattervarietygenerallybreedstrue。Thusneitherparenthadatraceofblueintheplumage，orofbarsonthewingandtail。IshouldpremisethatcommonTumblersarerarelyblueinEngland。FromtheabovecrossIrearedseveralyoung:onewasredoverthewholeback，butwiththetailasblueasthatoftherock—pigeon;
theterminalbar，however，wasabsent，buttheouterfeatherswereedgedwithwhite:asecondandthirdnearlyresembledthefirst，butthetailinbothpresentedatraceofthebarattheend:afourthwasbrownish，andthewingsshowedatraceofthedoublebar:afifthwaspaleblueoverthewholebreast，back，croup，andtail，buttheneckandprimarywing—featherswerereddish;thewingspresentedtwodistinctbarsofaredcolour;thetailwasnotbarred，buttheouterfeatherswereedgedwithwhite。I
crossedthislastcuriouslycolouredbirdwithablackmongrelofcomplicateddescent，namely，fromablackBarb，aSpot，andAlmond—tumbler，sothatthetwoyoungbirdsproducedfromthiscrossincludedthebloodoffivevarieties，noneofwhichhadatraceofblueorofwingandtail—bars:
oneofthetwoyoungbirdswasbrownish—black，withblackwing—bars;theotherwasreddish—dun，withreddishwing—bars，palerthantherestofthebody，withthecrouppaleblue，thetailbluishwithatraceoftheterminalbar。
Mr。Eaton（6/27。’TreatiseonPigeons’1858page145。）matchedtwoShort—
facedTumblers，namely，asplashcockandkitehen（neitherofwhichareblueorbarred），andfromthefirstnesthegotaperfectbluebird，andfromthesecondasilverorpalebluebird，bothofwhich，inaccordancewithallanalogy，nodoubtpresentedtheusualcharacteristicmarks。
IcrossedtwomaleblackBarbswithtwofemaleredSpots。Theselatterhavethewholebodyandwingswhite，withaspotontheforehead，thetailandtail—covertsred;theraceexistedatleastaslongagoas1676，andnowbreedsperfectlytrue，aswasknowntobethecaseintheyear1735。（6/28。
J。Moore’Columbarium’1735;inJ。M。Eaton’sedition1852page71。）Barbsareuniformly—colouredbirds，withrarelyevenatraceofbarsonthewingortail;theyareknowntobreedverytrue。Themongrelsthusraisedwereblackornearlyblack，ordarkorpalebrown，sometimesslightlypiebaldwithwhite:ofthesebirdsnolessthansixpresenteddoublewing—bars;intwothebarswereconspicuousandquiteblack;insevensomewhitefeathersappearedonthecroup;andintwoorthreetherewasatraceoftheterminalbartothetail，butinnoneweretheoutertail—feathersedgedwithwhite。
IcrossedblackBarbs（oftwoexcellentstrains）withpurely—bred，snow—
whiteFantails。Themongrelsweregenerallyquiteblack，withafewoftheprimarywingandtailfeatherswhite:othersweredarkreddish—brown，andotherssnow—white:nonehadatraceofwing—barsorofthewhitecroup。I
thenpairedtogethertwoofthesemongrels，namely，abrownandblackbird，andtheiroffspringdisplayedwing—bars，faint，butofadarkerbrownthantherestofbody。Inasecondbroodfromthesameparentsabrownbirdwasproduced，withseveralwhitefeathersconfinedtothecroup。
IcrossedamaledunDragonbelongingtoafamilywhichhadbeendun—
colouredwithoutwing—barsduringseveralgenerations，withauniformredBarb（bredfromtwoblackBarbs）;andtheoffspringpresenteddecidedbutfainttracesofwing—bars。IcrossedauniformredmaleRuntwithaWhitetrumpeter;andtheoffspringhadaslaty—bluetailwithabarattheend，andwiththeouterfeathersedgedwithwhite。IalsocrossedafemaleblackandwhitechequeredTrumpeter（ofadifferentstrainfromthelast）withamaleAlmond—tumbler，neitherofwhichexhibitedatraceofblue，orofthewhitecroup，orofthebaratendoftail:norisitprobablethattheprogenitorsofthesetwobirdshadformanygenerationsexhibitedanyofthesecharacters，forIhaveneverevenheardofablueTrumpeterinthiscountry，andmyAlmond—tumblerwaspurelybred;yetthetailofthismongrelwasbluish，withabroadblackbarattheend，andthecroupwasperfectlywhite。Itmaybeobservedinseveralofthesecases，thatthetailfirstshowsatendencytobecomebyreversionblue;andthisfactofthepersistencyofcolourinthetailandtail—coverts（6/29。Icouldgivenumerousexamples;twowillsuffice。Amongrel，whosefourgrandparentswereawhiteTurbit，whiteTrumpeter，whiteFantail，andbluePouter，waswhiteallover，exceptaveryfewfeathersabouttheheadandonthewings，butthewholetailandtail—covertsweredarkbluish—grey。AnothermongrelwhosefourgrandparentswerearedRunt，whiteTrumpeter，whiteFantail，andthesamebluePouter，waspurewhiteallover，exceptthetailandupperaill—coverts，whichwerepalefawn，andexceptthefaintesttraceofdoublewing—barsofthesamepalefawntint。）willsurprisenoonewhohasattendedtothecrossingofpigeons。
ThelastcasewhichIwillgiveisthemostcurious。IpairedamongrelfemaleBarb—fantailwithamongrelmaleBarb—spot;neitherofwhichmongrelshadtheleastblueaboutthem。LetitberememberedthatblueBarbsareexcessivelyrare;thatSpots，ashasbeenalreadystated，wereperfectlycharacterisedintheyear1676，andbreedperfectlytrue;thislikewiseisthecasewithwhiteFantails，somuchsothatIhaveneverheardofwhiteFantailsthrowinganyothercolour。Neverthelesstheoffspringfromtheabovetwomongrelswasofexactlythesamebluetintasthatofthewildrock—pigeonfromtheShetlandIslandsoverthewholebackandwings;thedoubleblackwing—barswereequallyconspicuous;thetailwasexactlyalikeinallitscharacters，andthecroupwaspurewhite;thehead，however，wastintedwithashadeofred，evidentlyderivedfromtheSpot，andwasofapalerbluethanintherock—pigeon，aswasthestomach。
SothattwoblackBarbs，aredSpot，andawhiteFantail，asthefourpurely—bredgrandparents，producedabirdexhibitingthegeneralbluecolour，togetherwitheverycharacteristicmark，thewildColumbalivia。
Withrespecttocrossedbreedsfrequentlyproducingbluebirdschequeredwithblack，andresemblinginallrespectsboththedovecote—pigeonandthechequeredwildvarietyoftherock—pigeon，thestatementbeforereferredtobyMM。BoitardandCorbiewouldalmostsuffice;butIwillgivethreeinstancesoftheappearanceofsuchbirdsfromcrossesinwhichonealoneoftheparentsorgreat—grandparentswasblue，butnotchequered。IcrossedamaleblueTurbitwithasnow—whiteTrumpeter，andthefollowingyearwithadark，leaden—brown，Short—facedTumbler;theoffspringfromthefirstcrosswereasperfectlychequeredasanydovecote—pigeon;andfromthesecond，somuchsoastobenearlyasblackasthemostdarklychequeredrock—pigeonfromMadeira。Anotherbird，whosegreat—grandparentswereawhiteTrumpeter，awhiteFantail，awhiteRed—spot，aredRunt，andabluePouter，wasslaty—blueandchequeredexactlylikeadovecote—pigeon。ImayhereaddaremarkmadetomebyMr。Wicking，whohashadmoreexperiencethananyotherpersoninEnglandinbreedingpigeonsofvariouscolours:
namely，thatwhenablue，orablueandchequeredbird，havingblackwing—
bars，onceappearsinanyraceandisallowedtobreed，thesecharactersaresostronglytransmittedthatitisextremelydifficulttoeradicatethem。
What，then，arewetoconcludefromthistendencyinallthechiefdomesticraces，bothwhenpurelybredandmoreespeciallywhenintercrossed，toproduceoffspringofabluecolour，withthesamecharacteristicmarks，varyinginthesamemanner，asinColumbialivia？IfweadmitthattheseracesarealldescendedfromC。livia，nobreederwilldoubtthattheoccasionalappearanceofbluebirdsthuscharacterisedisaccountedforonthewell—knownprincipleof\"throwingback\"orreversion。Whycrossingshouldgivesostrongatendencytoreversion，wedonotwithcertaintyknow;butabundantevidenceofthisfactwillbegiveninthefollowingchapters。ItisprobablethatImighthavebredevenforacenturypureblackBarbs，Spots，Nuns，whiteFantails，Trumpeters，etc。，withoutobtainingasingleblueorbarredbird;yetbycrossingthesebreedsI
rearedinthefirstandsecondgeneration，duringthecourseofonlythreeorfouryears，aconsiderablenumberofyoungbirds，moreorlessplainlycolouredblue，andwithmostofthecharacteristicmarks。Whenblackandwhite，orblackandredbirds，arecrossed，itwouldappearthataslighttendencyexistsinbothparentstoproduceblueoffspring，andthatthis，whencombined，overpowerstheseparatetendencyineitherparenttoproduceblack，orwhite，orredoffspring。
IfwerejectthebeliefthatalltheracesofthepigeonarethemodifieddescendantsofC。livia，andsupposethattheyaredescendedfromseveralaboriginalstocks，thenwemustchoosebetweenthethreefollowingassumptions:firstly，thatatleasteightorninespeciesformerlyexistedwhichwereaboriginallycolouredinvariousways，buthavesincevariedinexactlythesamemannersoastoassumethecolouringofC。livia;butthisassumptionthrowsnottheleastlightontheappearanceofsuchcoloursandmarkswhentheracesarecrossed。Orsecondly，wemayassumethattheaboriginalspecieswereallcolouredblue，andhadthewing—barsandothercharacteristicmarksofC。livia，——asuppositionwhichishighlyimprobable，asbesidesthisonespeciesnoexistingmemberoftheColumbidaepresentsthesecombinedcharacters;anditwouldnotbepossibletofindanyotherinstanceofseveralspeciesidenticalinplumage，yetasdifferentinimportantpointsofstructureasarePouters，Fantails，Carriers，Tumblers，etc。Orlastly，wemayassumethatalltheraces，whetherdescendedfromC。liviaorfromseveralaboriginalspecies，althoughtheyhavebeenbredwithsomuchcareandaresohighlyvaluedbyfanciers，haveallbeencrossedwithinadozenorscoreofgenerationswithC。livia，andhavethusacquiredtheirtendencytoproducebluebirdswiththeseveralcharacteristicmarks。IhavesaidthatitmustbeassumedthateachracehasbeencrossedwithC。liviawithinadozen，or，attheutmost，withinascoreofgenerations;forthereisnoreasontobelievethatcrossedoffspringeverreverttooneoftheirancestorswhenremovedbyagreaternumberofgenerations。Inabreedwhichhasbeencrossedonlyonce，thetendencytoreversionwillnaturallybecomelessandlessinthesucceedinggenerations，asineachtherewillbelessandlessofthebloodoftheforeignbreed;butwhentherehasbeennocrosswithadistinctbreed，andthereisatendencyinbothparentstoreverttosomelong—lostcharacter，thistendency，forallthatwecanseetothecontrary，maybetransmittedundiminishedforanindefinitenumberofgenerations。Thesetwodistinctcasesofreversionareoftenconfoundedtogetherbythosewhohavewrittenoninheritance。
Considering，ontheonehand，theimprobabilityofthethreeassumptionswhichhavejustbeendiscussed，and，ontheotherhand，howsimplythefactsareexplainedontheprincipleofreversion，wemayconcludethattheoccasionalappearanceinalltheraces，bothwhenpurelybredandmoreespeciallywhencrossed，ofbluebirds，sometimeschequered，withdoublewing—bars，withwhiteorbluecroups，withabarattheendofthetail，andwiththeoutertail—feathersedgedwithwhite，affordsanargumentofthegreatestweightinfavouroftheviewthatallaredescendedfromColumbalivia，includingunderthisnamethethreeorfourwildvarietiesorsub—speciesbeforeenumerated。
Tosumupthesixforegoingarguments，whichareopposedtothebeliefthatthechiefdomesticracesarethedescendantsofatleasteightornineorperhapsadozenspecies;forthecrossingofanylessnumberwouldnotyieldthecharacteristicdifferencesbetweentheseveralraces。FIRSTLY，theimprobabilitythatsomanyspeciesshouldstillexistsomewhere，butbeunknowntoornithologists，orthattheyshouldhavebecomewithinthehistoricalperiodextinct，althoughmanhashadsolittleinfluenceinexterminatingthewildC。livia。SECONDLY，theimprobabilityofmaninformertimeshavingthoroughlydomesticatedandrenderedfertileunderconfinementsomanyspecies。THIRDLY，thesesupposedspecieshavingnowherebecomeferal。FOURTHLY，theextraordinaryfactthatmanshould，intentionallyorbychance，havechosenfordomesticationseveralspecies，extremelyabnormalincharacter;andfurthermore，thepointsofstructurewhichrenderthesesupposedspeciessoabnormalbeingnowhighlyvariable。
FIFTHLY，thefactofalltheraces，thoughdifferinginmanyimportantpointsofstructure，producingperfectlyfertilemongrels;whilstallthehybridswhichhavebeenproducedbetweenevencloselyalliedspeciesinthepigeon—familyaresterile。SIXTHLY，theremarkablestatementsjustgivenonthetendencyinalltheraces，bothwhenpurelybredandwhencrossed，torevertinnumerousminutedetailsofcolouringtothecharacterofthewildrock—pigeon，andtovaryinasimilarmanner。Totheseargumentsmaybeaddedtheextremeimprobabilitythatanumberofspeciesformerlyexisted，whichdifferedgreatlyfromeachotherinsomefewpoints，butwhichresembledeachotherascloselyasdothedomesticracesinotherpointsofstructure，invoice，andinalltheirhabitsoflife。Whentheseseveralfactsandargumentsarefairlytakenintoconsideration，itwouldrequireanoverwhelmingamountofevidencetomakeusadmitthatthechiefdomesticracesaredescendedfromseveralaboriginalstocks;andofsuchevidencethereisabsolutelynone。
Thebeliefthatthechiefdomesticracesaredescendedfromseveralwildstocksnodoubthasarisenfromtheapparentimprobabilityofsuchgreatmodificationsofstructurehavingbeeneffectedsincemanfirstdomesticatedtherock—pigeon。NoramIsurprisedatanydegreeofhesitationinadmittingtheircommonparentage:formerly，whenIwentintomyaviariesandwatchedsuchbirdsasPouters，Carriers，Barbs，Fantails，andShort—facedTumblers，etc。，Icouldnotpersuademyselfthatallhaddescendedfromthesamewildstock，andthatmanhadconsequentlyinonesensecreatedtheseremarkablemodifications。ThereforeIhavearguedthequestionoftheiroriginatgreat，and，assomewillthink，superfluouslength。
Finally，infavourofthebeliefthatalltheracesaredescendedfromasinglestock，wehaveinColumbaliviaastillexistingandwidelydistributedspecies，whichcanbeandhasbeendomesticatedinvariouscountries。Thisspeciesagreesinmostpointsofstructureandinallitshabitsoflife，aswellasoccasionallyineverydetailofplumage，withtheseveraldomesticraces。Itbreedsfreelywiththem，andproducesfertileoffspring。Itvariesinastateofnature（6/30。Itdeservesnotice，asbearingonthegeneralsubjectofvariation，thatnotonlyC。