IfthehistoryofthesePortoSantorabbitshadnotbeenknown，mostnaturalists，onobservingtheirmuchreducedsize，theircolour，reddishaboveandgreybeneath，theirtailsandearsnottippedwithblack，wouldhaverankedthemasadistinctspecies。TheywouldhavebeenstronglyconfirmedinthisviewbyseeingthemaliveintheZoologicalGardens，andhearingthattheyrefusedtocouplewithotherrabbits。Yetthisrabbit，whichtherecanbelittledoubtwouldthushavebeenrankedasadistinctspecies，ascertainlyoriginatedsincetheyear1420。Finally，fromthethreecasesoftherabbitswhichhaverunwildinPortoSanto，Jamaica，andtheFalklandIslands，weseethattheseanimalsdonot，undernewconditionsoflife，reverttoorretaintheiraboriginalcharacter，asissogenerallyassertedtobethecasebymostauthors。
OSTEOLOGICALCHARACTERS。
Whenweremember，ontheonehand，howfrequentlyitisstatedthatimportantpartsofthestructurenevervary;and，ontheotherhand，onwhatsmalldifferencesintheskeletonfossilspecieshaveoftenbeenfounded，thevariabilityoftheskullandofsomeotherbonesinthedomesticatedrabbitwelldeservesattention。Itmustnotbesupposedthatthemoreimportantdifferencesimmediatelytobedescribedstrictlycharacteriseanyonebreed;allthatcanbesaidis，thattheyaregenerallypresentincertainbreeds。Weshouldbearinmindthatselectionhasnotbeenappliedtofixanycharacterintheskeleton，andthattheanimalshavenothadtosupportthemselvesunderuniformhabitsoflife。Wecannotaccountformostofthedifferencesintheskeleton;butweshallseethattheincreasedsizeofthebody，duetocarefulnurtureandcontinuedselection，hasaffectedtheheadinaparticularmanner。Eventheelongationandloppingoftheearshaveinfluencedinasmalldegreetheformofthewholeskull。Thewantofexercisehasapparentlymodifiedtheproportionallengthofthelimbsincomparisonwiththatofthebody。
[Asastandardofcomparison，IpreparedskeletonsoftwowildrabbitsfromKent，onefromtheShetlandIslands，andonefromAntriminIreland。Asallthebonesinthesefourspecimensfromsuchdistantlocalitiescloselyresembledeachother，presentingscarcelyanyappreciabledifference，itmaybeconcludedthatthebonesofthewildrabbitaregenerallyuniformincharacter。
SKULL。
Ihavecarefullyexaminedskullsoftenlargelop—earedrabbits，andoffivecommondomesticrabbits，whichlatterdifferfromthelop—earedonlyinnothavingsuchlargebodiesorears，yetbothlargerthaninthewildrabbit。Firstforthetenlop—earedrabbits:inallthesetheskullisremarkablyelongatedincomparisonwithitsbreadth。Inawildrabbitthelengthwas3。15inches，inalargefancyrabbit4。3;whilstthebreadthofthecraniumenclosingthebrainwasinbothalmostexactlythesame。Evenbytakingasthestandardofcomparisonthewidestpartofthezygomaticarch，theskullsofthelop—earedareproportionallytotheirbreadththree—quartersofaninchtoolong。Thedepthoftheheadhasincreasedalmostinthesameproportionwiththelength;itisthebreadthalonewhichhasnotincreased。Theparietalandoccipitalbonesenclosingthebrainarelessarched，bothinalongitudinalandtransverseline，thaninthewildrabbit，sothattheshapeofthecraniumissomewhatdifferent。
Thesurfaceisrougher，lesscleanlysculptured，andthelinesofsuturesaremoreprominent。
Althoughtheskullsofthelargelop—earedrabbitsincomparisonwiththoseofthewildrabbitaremuchelongatedrelativelytotheirbreadth，yet，relativelytothesizeofbody，theyarefarfromelongated。Thelop—earedrabbitswhichIexaminedwere，thoughnotfat，morethantwiceasheavyasthewildspecimens;buttheskullwasveryfarfrombeingtwiceaslong。
Evenifwetakethefairerstandardofthelengthofbody，fromthenosetotheanus，theskullisnotonanaverageaslongasitoughttobebyathirdofaninch。InthesmallferalPortoSantorabbit，ontheotherhand，theheadrelativelytothelengthofbodyisaboutaquarterofaninchtoolong。
Thiselongationoftheskullrelativelytoitsbreadth，Ifindauniversalcharacter，notonlywiththelargelop—earedrabbits，butinalltheartificialbreeds;asiswellseenintheskulloftheAngora。Iwasatfirstmuchsurprisedatthefact，andcouldnotimaginewhydomesticationcouldproducethisuniformresult;buttheexplanationseemstolieinthecircumstancethatduringanumberofgenerationstheartificialraceshavebeencloselyconfined，andhavehadlittleoccasiontoexerteithertheirsenses，orintellect，orvoluntarymuscles;consequentlythebrain，asweshallpresentlymorefullysee，hasnotincreasedrelativelywiththesizeofbody。Asthebrainhasnotincreased，thebonycaseenclosingithasnotincreased，andthishasevidentlyaffectedthroughcorrelationthebreadthoftheentireskullfromendtoend。
（FIGURE6。SKULLOFWILDRABBIT，ofnaturalsize。
FIGURE7。SKULLOFLARGELOP—EAREDRABBIT，ofnaturalsize。
FIGURE8。PARTOFZYGOMATICARCH，showingtheprojectingendofthemalarboneoftheauditorymeatus:ofnaturalsize。Upperfigure，WildRabbit。
Lowerfigure，Lop—eared，hare—colouredRabbit。
FIGURE9。POSTERIORENDOFSKULL，ofnaturalsize，showingtheinter—
parietalbone。A。WildRabbit。B。FeralRabbitfromislandofP。Santo，nearMadeira。C。LargeLop—earedRabbit。）
Inalltheskullsofthelargelop—earedrabbits，thesupra—orbitalplatesorprocessesofthefrontalbonesaremuchbroaderthaninthewildrabbit，andtheygenerallyprojectmoreupwards。Inthezygomaticarchtheposteriororprojectingpointofthemalar—boneisbroaderandblunter;andinthespecimen，figure8，itissoinaremarkabledegree。Thispointapproachesnearertotheauditorymeatusthaninthewildrabbit，asmaybebestseeninfigure8;butthiscircumstancemainlydependsonthechangeddirectionofthemeatus。Theinter—parietalbone（seefigure9）differsmuchinshapeintheseveralskulls;generallyitismoreoval，thatismoreextendedinthelineofthelongitudinalaxisoftheskull，thaninthewildrabbit。Theposteriormarginof"thesquareraisedplatform"
（4/25。Waterhouse’Nat。Hist。Mammalia’volume2page36。）oftheocciput，insteadofbeingtruncated，orprojectingslightlyasinthewildrabbit，isinmostlop—earedrabbitspointed，asinfigure9，C。Theparamastoidsrelativelytothesizeoftheskullaregenerallymuchthickerthaninthewildrabbit。
（FIGURE10。OCCIPITALFORAMEN，ofnaturalsize，in——A。WildRabbit;B。
LargeLop—earedRabbit。）
Theoccipitalforamen（figure10）presentssomeremarkabledifferences:inthewildrabbit，theloweredgebetweenthecondylesisconsiderablyandalmostangularlyhollowedout，andtheupperedgeisdeeplyandsquarelynotched;hencethelongitudinalaxisexceedsthetransverseaxis。Intheskullsofthelop—earedrabbitsthetransverseaxisexceedsthelongitudinal;forinnoneoftheseskullswastheloweredgebetweenthecondylessodeeplyhollowedout;infiveofthemtherewasnouppersquarenotch，inthreetherewasatraceofthenotch，andintwoaloneitwaswelldeveloped。Thesedifferencesintheshapeoftheforamenareremarkable，consideringthatitgivespassagetosoimportantastructureasthespinalmarrow，thoughapparentlytheoutlineofthelatterisnotaffectedbytheshapeofthepassage。
（FIGURE11。SKULL，ofnaturalsize，ofHalf—lopRabbit，showingthedifferentdirectionoftheauditorymeatusonthetwosides，andtheconsequentgeneraldistortionoftheskull。Theleftearoftheanimal（orrightsideoffigure）loppedforwards。）
Inalltheskullsofthelargelop—earedrabbits，thebonyauditorymeatusisconspicuouslylargerthaninthewildrabbit。Inaskull4。3inchesinlength，andwhichbarelyexceededinbreadththeskullofawildrabbit（whichwas3。15inchesinlength），thelongerdiameterofthemeatuswasexactlytwiceasgreat。Theorificeismorecompressed，anditsmarginonthesidenearesttheskullstandsuphigherthantheouterside。Thewholemeatusisdirectedmoreforwards。Asinbreedinglop—earedrabbitsthelengthoftheears，andtheirconsequentloppingandlyingflatontheface，arethechiefpointsofexcellence，therecanhardlybeadoubtthatthegreatchangeinthesize，form，anddirectionofthebonymeatus，relativelytothissamepartinthewildrabbit，isduetothecontinuedselectionofindividualshavinglargerandlargerears。Theinfluenceoftheexternalearonthebonymeatusiswellshownintheskulls（Ihaveexaminedthree）ofhalf—lops（seefigure5），inwhichoneearstandsupright，andtheotherandlongerearhangsdown;forintheseskullstherewasaplaindifferenceintheformanddirectionofthebonymeatusonthetwosides。Butitisamuchmoreinterestingfact，thatthechangeddirectionandincreasedsizeofthebonymeatushaveslightlyaffectedonthesamesidethestructureofthewholeskull。Iheregiveadrawing（figure11）oftheskullofahalf—lop;anditmaybeobservedthatthesuturebetweentheparietalandfrontalbonesdoesnotrunstrictlyatrightanglestothelongitudinalaxisoftheskull;theleftfrontalboneprojectsbeyondtherightone;boththeposteriorandanteriormarginsoftheleftzygomaticarchonthesideoftheloppingearstandalittleinadvanceofthecorrespondingbonesontheoppositeside。Eventhelowerjawisaffected，andthecondylesarenotquitesymmetrical，thatontheleftstandingalittleinadvanceofthatontheright。Thisseemstomearemarkablecaseofcorrelationofgrowth。Whowouldhavesurmisedthatbykeepingananimalduringmanygenerationsunderconfinement，andsoleadingtothedisuseofthemusclesoftheears，andbycontinuallyselectingindividualswiththelongestandlargestears，hewouldthusindirectlyhaveaffectedalmosteverysutureintheskullandtheformofthelowerjaw！
Inthelargelop—earedrabbitstheonlydifferenceinthelowerjaw，incomparisonwiththatofthewildrabbit，isthattheposteriormarginoftheascendingramusisbroaderandmoreinflected。Theteethinneitherjawpresentanydifference，exceptthatthesmallincisors，beneaththelargeones，areproportionatelyalittlelonger。Themolarteethhaveincreasedinsizeproportionatelywiththeincreasedwidthoftheskull，measuredacrossthezygomaticarch，andnotproportionallywithitsincreasedlength。Theinnerlineofthesocketsofthemolarteethintheupperjawofthewildrabbitformsaperfectlystraightline;butinsomeofthelargestskullsofthelop—earedthislinewasplainlybowedinwards。Inonespecimentherewasanadditionalmolartoothoneachsideoftheupperjaw，betweenthemolarsandpremolars;butthesetwoteethdidnotcorrespondinsize;andasnorodenthassevenmolars，thisismerelyamonstrosity，thoughacuriousone。
Thefiveotherskullsofcommondomesticrabbits，someofwhichapproachinsizetheabove—describedlargestskulls，whilsttheothersexceedbutlittlethoseofthewildrabbit，areonlyworthnoticeaspresentingaperfectgradationinalltheabove—specifieddifferencesbetweentheskullsofthelargestlop—earedandwildrabbits。Inall，however，thesupra—
orbitalplatesareratherlarger，andinalltheauditorymeatusislarger，inconformitywiththeincreasedsizeoftheexternalears，thaninthewildrabbit。Thelowernotchintheoccipitalforameninsomewasnotsodeepasinthewildrabbit，butinallfiveskullstheuppernotchwaswelldeveloped。
TheskulloftheAngorarabbit，likethelatterfiveskulls，isintermediateingeneralproportions，andinmostothercharacters，betweenthoseofthelargestlop—earedandwildrabbits。Itpresentsonlyonesingularcharacter:thoughconsiderablylongerthantheskullofthewildrabbit，thebreadthmeasuredwithintheposteriorsupra—orbitalfissuresisnearlyathirdlessthaninthewild。Theskullsofthesilver—grey，andchinchillaandHimalayanrabbitsaremoreelongatedthaninthewild，withbroadersupra—orbitalplates，butdifferlittleinanyotherrespect，exceptingthattheupperandlowernotchesoftheoccipitalforamenarenotsodeeporsowelldeveloped。TheskulloftheMoscowrabbitscarcelydiffersatallfromthatofthewildrabbit。InthePortoSantoferalrabbitsthesupra—orbitalplatesaregenerallynarrowerandmorepointedthaninourwildrabbits。
Assomeofthelargestlop—earedrabbitsofwhichIpreparedskeletonswerecolouredalmostlikehares，andastheselatteranimalsandrabbitshave，asitisaffirmed，beenrecentlycrossedinFrance，itmightbethoughtthatsomeoftheabove—describedcharactershadbeenderivedfromacrossataremoteperiodwiththehare。ConsequentlyIexaminedskullsofthehare，butnolightcouldthusbethrownonthepeculiaritiesoftheskullsofthelargerrabbits。Itis，however，aninterestingfact，asillustratingthelawthatvarietiesofonespeciesoftenassumethecharactersofotherspeciesofthesamegenus，thatIfound，oncomparingtheskullsoftenspeciesofharesintheBritishMuseum，thattheydifferedfromeachotherchieflyintheverysamepointsinwhichdomesticrabbitsvary，——namely，ingeneralproportions，intheformandsizeofthesupra—orbitalplates，intheformofthefreeendofthemalarbone，andinthelineofsutureseparatingtheoccipitalandfrontalbones。Moreovertwoeminentlyvariablecharactersinthedomesticrabbit，namely，theoutlineoftheoccipitalforamenandtheshapeofthe"raisedplatform"oftheocciput，werelikewisevariableintwoinstancesinthesamespeciesofhare。
VERTEBRAE。
ThenumberisuniforminalltheskeletonswhichIhaveexamined，withtwoexceptions，namely，inoneofthesmallferalPortoSantorabbitsandinoneofthelargestlop—earedkinds;bothofthesehadasusualsevencervical，twelvedorsalwithribs，but，insteadofsevenlumbar，bothhadeightlumbarvertebrae。Thisisremarkable，asGervaisgivessevenasthenumberforthewholegenusLepus。Thecaudalvertebraeapparentlydifferbytwoorthree，butIdidnotattendtothem，andtheyaredifficulttocountwithcertainty。
（FIGURE12。ATLASVERTEBRAE，ofnaturalsize;inferiorsurfaceviewedobliquely。Upperfigure，WildRabbit。Lowerfigure，Hare—coloured，large，Lop—earedRabbit，a，supra—median，atlantoidprocess;b，infra—medianprocess。）
Inthefirstcervicalvertebra，oratlas，theanteriormarginoftheneuralarchvariesalittleinwildspecimens，beingeithernearlysmooth，orfurnishedwithasmallsupra—medianatlantoidprocess;Ihavefiguredaspecimenwiththelargestprocess（a）whichIhaveseen;butitwillbeobservedhowinferiorthisisinsizeanddifferentinshapetothatinalargelop—earedrabbit。Inthelatter，theinfra—medianprocess（b）isalsoproportionallymuchthickerandlonger。Thealaearealittlesquarerinoutline。
（FIGURE13。THIRDCERVICALVERTEBRAE，ofnaturalsize，of:A。WildRabbit;
B。Hare—coloured，large，Lop—earedRabbit，a，a，inferiorsurface;b，b，anteriorarticularsurfaces。）
THIRDCERVICALVERTEBRA。
Inthewildrabbit（figure13，Aa）thisvertebra，viewedontheinferiorsurface，hasatransverseprocess，whichisdirectedobliquelybackwards，andconsistsofasinglepointedbar;inthefourthvertebrathisprocessisslightlyforkedinthemiddle。Inthelargelop—earedrabbitsthisprocess（Ba）isforkedinthethirdvertebra，asinthefourthofthewildrabbit。Butthethirdcervicalvertebraeofthewildandlop—eared（Ab，B
b）rabbitsdiffermoreconspicuouslywhentheiranteriorarticularsurfacesarecompared;fortheextremitiesoftheantero—dorsalprocessesinthewildrabbitaresimplyrounded，whilstinthelop—earedtheyaretrifid，withadeepcentralpit。Thecanalforthespinalmarrowinthelop—eared（Bb）ismoreelongatedinatransversedirectionthaninthewildrabbit;
andthepassagesforthearteriesareofaslightlydifferentshape。Theseseveraldifferencesinthisvertebraseemtomewelldeservingattention。
FIRSTDORSALVERTEBRA。
Itsneuralspinevariesinlengthinthewildrabbit;beingsometimesveryshort，butgenerallymorethanhalfaslongasthatoftheseconddorsal;
butIhaveseenitintwolargelop—earedrabbitsthree—fourthsofthelengthofthatoftheseconddorsalvertebra。
（FIGURE14。DORSALVERTEBRAE，fromsixthtotenthinclusive，ofnaturalsize，viewedlaterally。A。WildRabbit。B。Large，Hare—coloured，socalledSpanishRabbit。）
NINTHANDTENTHDORSALVERTEBRAE。
Inthewildrabbittheneuralspineoftheninthvertebraisjustperceptiblythickerthanthatoftheeighth;andtheneuralspineofthetenthisplainlythickerandshorterthanthoseofalltheanteriorvertebrae。Inthelargelop—earedrabbitstheneuralspinesofthetenth，ninth，andeighthvertebrae，andeveninaslightdegreethatoftheseventh，areverymuchthicker，andofsomewhatdifferentshape，incomparisonwiththoseofthewildrabbit。Sothatthispartofthevertebralcolumndiffersconsiderablyinappearancefromthesamepartinthewildrabbit，andcloselyresemblesinaninterestingmannerthesesamevertebraeinsomespeciesofhares。IntheAngora，Chinchilla，andHimalayanrabbits，theneuralspinesoftheeighthandninthvertebraeareinaslightdegreethickerthaninthewild。Ontheotherhand，inoneoftheferalPortoSantorabbits，whichinmostofitscharactersdeviatesfromthecommonwildrabbit，inadirectionexactlyoppositetothatassumedbythelargelop—earedrabbits，theneuralspinesoftheninthandtenthvertebraewerenotatalllargerthanthoseoftheseveralanteriorvertebra。InthissamePortoSantospecimentherewasnotraceintheninthvertebraoftheanteriorlateralprocesses（seefigure14），whichareplainlydevelopedinallBritishwildrabbits，andstillmoreplainlydevelopedinthelargelop—earedrabbits。Inahalf—wildrabbitfromSandonPark（4/26。TheserabbitshaverunwildforaconsiderabletimeinSandonPark，andinotherplacesinStaffordshireandShropshire。Theyoriginated，asIhavebeeninformedbythegamekeeper，fromvariously—coloureddomesticrabbitswhichhadbeenturnedout。Theyvaryincolour;butmanyaresymmetricallycoloured，beingwhitewithastreakalongthespine，andwiththeearsandcertainmarksabouttheheadofablackish—greytint。Theyhaveratherlongerbodiesthancommonrabbits），ahaemalspinewasmoderatelywelldevelopedontheundersideofthetwelfthdorsalvertebra，andIhaveseenthisinnootherspecimen。
LUMBARVERTEBRAE。
Ihavestatedthatintwocasestherewereeightinsteadofsevenlumbarvertebrae。ThethirdlumbarvertebraeinoneskeletonofawildBritishrabbit，andinoneofthePortoSantoferalrabbits，hadahaemalspine;
whilstinfourskeletonsoflargelop—earedrabbits，andintheHimalayanrabbit，thissamevertebrahadawelldevelopedhaemalspine。
PELVIS。
Infourwildspecimensthisbonewasalmostabsolutelyidenticalinshape;
butinseveraldomesticatedbreedsshadesofdifferencescouldbedistinguished。Inthelargelop—earedrabbits，thewholeupperpartoftheiliumisstraighter，orlesssplayedoutwards，thaninthewildrabbit;andthetuberosityontheinnerlipoftheanteriorandupperpartoftheiliumisproportionallymoreprominent。
（FIGURE15。TERMINALBONEOFSTERNUM，ofnaturalsize，A。WildRabbit。B。
Hare—coloured，Lop—earedRabbit。C。Hare—colouredSpanishRabbit。（N。B。Theleft—handangleoftheupperarticularextremityofBwasbroken，andhasbeenaccidentallythusrepresented。））
STERNUM。
Theposteriorendoftheposteriorsternalboneinthewildrabbit（figure15，A）isthinandslightlyenlarged;insomeofthelargelop—earedrabbits（B）itismuchmoreenlargedtowardstheextremity;whilstinotherspecimens（C）itkeepsnearlyofthesamebreadthfromendtoend，butismuchthickerattheextremity。
（FIGURE16。ACROMIONOFSCAPULA，ofnaturalsize。A。WildRabbit。B，C，D，Large，Lop—earedRabbits。）
SCAPULA。
Theacromionsendsoutarectangularbar，endinginanobliqueknob，whichlatterinthewildrabbit（figure16，A）variesalittleinshapeandsize，asdoestheapexoftheacromioninsharpness，andthepartjustbelowtherectangularbarinbreadth。Butthevariationsintheserespectsinthewildrabbitareveryslight:whilstinthelargelop—earedrabbitstheyareconsiderable。Thusinsomespecimens（B）theobliqueterminalknobisdevelopedintoashortbar，forminganobtuseanglewiththerectangularbar。Inanotherspecimen（C）thesetwounequalbarsformnearlyastraightline。Theapexoftheacromionvariesmuchinbreadthandsharpness，asmaybeseenbycomparingfiguresB，C，andD。
LIMBS。
IntheseIcoulddetectnovariation;butthebonesofthefeetweretootroublesometocomparewithmuchcare。]
IhavenowdescribedallthedifferencesintheskeletonswhichIhaveobserved。Itisimpossiblenottobestruckwiththehighdegreeofvariabilityorplasticityofmanyofthebones。Weseehowerroneoustheoften—repeatedstatementis，thatonlythecrestsoftheboneswhichgiveattachmenttomusclesvaryinshape，andthatonlypartsofslightimportancebecomemodifiedunderdomestication。Noonewillsay，forinstance，thattheoccipitalforamen，ortheatlas，orthethirdcervicalvertebraisapartofslightimportance。Iftheseveralvertebraeofthewildandlop—earedrabbits，ofwhichfigureshavebeengiven，hadbeenfoundfossil，palaeontologistswouldhavedeclaredwithouthesitationthattheyhadbelongedtodistinctspecies。
[THEEFFECTSOFTHEUSEANDDISUSEOFPARTS。
Inthelargelop—earedrabbitstherelativeproportionallengthofthebonesofthesameleg，andofthefrontandhindlegscomparedwitheachother，haveremainednearlythesameasinthewildrabbit;butinweight，thebonesofthehindlegsapparentlyhavenotincreasedindueproportionwiththefrontlegs。Theweightofthewholebodyinthelargerabbitsexaminedbymewasfromtwicetotwiceandahalfasgreatasthatofthewildrabbit;andtheweightofthebonesofthefrontandhindlimbstakentogether（excludingthefeet，onaccountofthedifficultyofcleaningsomanysmallbones）hasincreasedinthelargelop—earedrabbitsinnearlythesameproportion;consequentlyindueproportiontotheweightofbodywhichtheyhavetosupport。Ifwetakethelengthofthebodyasthestandardofcomparison，thelimbsofthelargerabbitshavenotincreasedinlengthindueproportionbyoneinchandahalf。Again，ifwetakeasthestandardofcomparisonthelengthoftheskull，which，aswehavebeforeseen，hasnotincreasedinlengthindueproportiontothelengthofbody，thelimbswillbefoundtobe，proportionallywiththoseofthewildrabbit，fromhalftothree—quartersofaninchtooshort。Hence，whateverstandardofcomparisonbetaken，thelimb—bonesofthelargelop—earedrabbitshavenotincreasedinlength，thoughtheyhaveinweight，infullproportiontotheotherpartsoftheframe;andthis，Ipresume，maybeaccountedforbytheinactivelifewhichduringmanygenerationstheyhavespent。Norhasthescapulaincreasedinlengthindueproportiontotheincreasedlengthofthebody。
Thecapacityoftheosseouscaseofthebrainisamoreinterestingpoint，towhichIwasledtoattendbyfinding，aspreviouslystated，thatwithalldomesticatedrabbitsthelengthoftheskullrelativelytoitsbreadthhasgreatlyincreasedincomparisonwiththatofthewildrabbits。Ifwehadpossessedalargenumberofdomesticatedrabbitsofnearlythesamesizewiththewildrabbits，itwouldhavebeenasimpletasktohavemeasuredandcomparedthecapacitiesoftheirskulls。Butthisisnotthecase:almostallthedomesticbreedshavelargerbodiesthanwildrabbits，andthelop—earedkindsaremorethandoubletheirweight。Asasmallanimalhastoexertitssenses，intellect，andinstinctsequallywithalargeanimal，weoughtnotbyanymeanstoexpectananimaltwiceorthriceaslargeasanothertohaveabrainofdoubleortreblethesize。（4/27。
SeeProf。Owen’sremarksonthissubjectinhispaperonthe’ZoologicalSignificanceoftheBrain，etc。，ofMan，etc。’readbeforeBrit。
Association1862:withrespecttoBirdssee’Proc。Zoolog。Soc。’January11，1848page8。）Now，afterweighingthebodiesoffourwildrabbits，andoffourlargebutnotfattenedlop—earedrabbits，Ifindthatonanaveragethewildaretothelop—earedinweightas1to2。17;inaveragelengthofbodyas1to1。41;whilstincapacityofskulltheyareas1to1。15。Henceweseethatthecapacityoftheskull，andconsequentlythesizeofthebrain，hasincreasedbutlittle，relativelytotheincreasedsizeofthebody;andthisfactexplainsthenarrownessoftheskullrelativelytoitslengthinalldomesticrabbits。
TABLE3:MEASUREMENTSOFWILDANDSEMI—WILDRABBITS。
I。LengthofSkull（inches）。
II。LengthofBodyfromIncisorstoAnus（inches）。
III。WeightofwholeBody（poundsandounces）。
IV。CapacityofSkullmeasuredbySmallShot（grains）。
V。CapacitycalculatedaccordingtoLengthofSkullrelativelytothatofNo。1（WildRabbit，Kent）（grains）。
VI。DifferencebetweenactualandcalculatedcapacitiesofSkulls（grains）。
VII。ShowinghowmuchpercenttheBrain，bycalculationaccordingtothelengthoftheSkullistoolight（—）ortooheavy（），relativelytotheBrainoftheWildRabbitNo。1。
NAMEOFBREED:I。II。III。IV。V。VI。
VII。
WILDANDSEMI—WILDRABBITS:
1。WildRabbit，Kent:3。1517。43，5972……
2
2。WildRabbit，ShetlandIslands:3。15……979……
2
3。WildRabbit，Ireland:3。15……992……
2
4。Domesticrabbit，runwild，Sandon:3。1518。5……977……
2
5。Wild，commonvariety，smallspecimen，Kent:2。9617。02，1487591338—
4
6。Wild，fawn—colouredvariety，Scotland:3。1……91895032—
3
7。Silver—grey，smallspecimen，Thetfordwarren:2。9515。52，1193891028
3
8。Feralrabbit，PortoSanto:2。83……89387320
2
9。Feralrabbit，PortoSanto:2。85……756879123—
16
10。Feralrabbit，PortoSanto:2。95……83591075—
9
AverageofthreePortoSantorabbits:2。88……82888860—
7
DOMESTICRABBITS:
11。Himalayan:3。520。5……9631080117—
12
12。Moscow:3。2517。03，88031002199—
24
13。Angora:3。519。53，16971080383—
54
14。Chinchilla:3。6522。0……9951126131—
13
15。Largelop—eared:4。124。57，010651265200—
18
16。Largelop—eared:4。125。07，1311531265112—
9
17。Largelop—eared:4。07……10371255218—
21
18。Largelop—eared:4。125。07，41208126557—
4
19。Largelop—eared:4。3……1232132694—
7
20。Largelop—eared:4。25……11241311187—
16
21。Largehare—coloured:3。8624。06，141131119160—
5
22。Averageofabovesevenlargelop—earedrabbits:4。1124。627，411361268132—
11
23。Hare（L。timidus）
Englishspecimen:3。617，01315
24。Hare（L。timidus）
Germanspecimen:3。827，01455
IntheupperhalfofTable3Ihavegiventhemeasurementsoftheskulloftenwildrabbits;andinthelowerhalf，ofeleventhoroughlydomesticatedkinds。Astheserabbitsdiffersogreatlyinsize，itisnecessarytohavesomestandardbywhichtocomparethecapacitiesoftheirskulls。Ihaveselectedthelengthofskullasthebeststandard，forinthelargerrabbitsithasnot，asalreadystated，increasedinlengthsomuchasthebody;butastheskull，likeeveryotherpart，variesinlength，neitheritnoranyotherpartaffordsaperfectstandard。
Inthefirstcolumnoffigurestheextremelengthoftheskullisgivenininchesanddecimals。Iamawarethatthesemeasurementspretendtogreateraccuracythanispossible;butIhavefoundittheleasttroubletorecordtheexactlengthwhichthecompassgave。Thesecondandthirdcolumnsgivethelengthandweightofbody，whenevertheseobservationsweremade。Thefourthcolumngivesthecapacityoftheskullbytheweightofsmallshotwithwhichtheskullswerefilled;butitisnotpretendedthattheseweightsareaccuratewithinafewgrains。Inthefifthcolumnthecapacityisgivenwhichtheskulloughttohavehadbycalculation，accordingtothelengthofskull，incomparisonwiththatofthewildrabbitNo。1;inthesixthcolumnthedifferencebetweentheactualandcalculatedcapacities，andinthesevenththepercentageofincreaseordecrease，aregiven。Forinstance，asthewildrabbitNo。5hasashorterandlighterbodythanthewildrabbitNo。1，wemighthaveexpectedthatitsskullwouldhavehadlesscapacity;theactualcapacity，asexpressedbytheweightofshot，is875grains，whichis97grainslessthanthatofthefirstrabbit。Butcomparingthesetworabbitsbythelengthoftheirskulls，weseethatinNo。1theskullis3。15inchesinlength，andinNo。52。96inchesinlength;accordingtothisratio，thebrainofNo。5oughttohavehadacapacityof913grainsofshot，whichisabovetheactualcapacity，butonlyby38grains。Or，toputthecaseinanotherway（asincolumnVII），thebrainofthissmallrabbit，No。5，forevery100grainsofweightisonly4grainstoolight，——thatis，itought，accordingtothestandardrabbitNo。1，tohavebeen4percentheavier。IhavetakentherabbitNo。
1asthestandardofcomparisonbecause，oftheskullshavingafullaveragelength，thishastheleastcapacity;sothatitistheleastfavourabletotheresultwhichIwishtoshow，namely，thatthebraininalllong—domesticatedrabbitshasdecreasedinsize，eitheractually，orrelativelytothelengthoftheheadandbody，incomparisonwiththebrainofthewildrabbit。HadItakentheIrishrabbit，No。3，asthestandard，thefollowingresultswouldhavebeensomewhatmorestriking。
TurningtoTable3:thefirstfourwildrabbitshaveskullsofthesamelength，andthesedifferbutlittleincapacity。TheSandonrabbit（No。4）
isinteresting，as，thoughnowwild，itisknowntobedescendedfromadomesticatedbreed，asisstillshownbyitspeculiarcolouringandlongerbody;neverthelesstheskullhasrecovereditsnormallengthandfullcapacity。Thenextthreerabbitsarewild，butofsmallsize，andtheyallhaveskullswithslightlylessenedcapacities。ThethreePortoSantoferalrabbits（Nos。8to10）offeraperplexingcase;theirbodiesaregreatlyreducedinsize，asinalesserdegreearetheirskullsinlengthandinactualcapacity，incomparisonwiththeskullsofwildEnglishrabbits。ButwhenwecomparethecapacitiesoftheskullinthethreePortoSantorabbits，weobserveasurprisingdifference，whichdoesnotstandinanyrelationtotheslightdifferenceinthelengthoftheirskulls，nor，asI
believe，toanydifferenceinthesizeoftheirbodies;butIneglectedweighingseparatelytheirbodies。Icanhardlysupposethatthemedullarymatterofthebraininthesethreerabbits，livingundersimilarconditions，candifferasmuchasisindicatedbytheproportionaldifferenceofcapacityintheirskulls;nordoIknowwhetheritispossiblethatonebrainmaycontainconsiderablymorefluidthananother。
HenceIcanthrownolightonthiscase。
LookingtothelowerhalfofTable3，whichgivesthemeasurementsofdomesticatedrabbits，weseethatinallthecapacityoftheskullisless，butinveryvariousdegrees，thanmighthavebeenanticipatedaccordingtothelengthoftheirskulls，relativelytothatofthewildrabbitNo。1。Inline22theaveragemeasurementsofsevenlargelop—earedrabbitsaregiven。Nowthequestionarises，hastheaveragecapacityoftheskullinthesesevenlargerabbitsincreasedasmuchasmighthavebeenexpectedfromthegreatlyincreasedsizeofbody。Wemayendeavourtoanswerthisquestionintwoways:intheupperhalfoftheTablewehavemeasurementsoftheskullsofsixsmallwildrabbits（Nos。5to10），andwefindthatonanaveragetheskullsare。18ofaninchshorter，andincapacity91grainsless，thantheaveragelengthandcapacityofthethreefirstwildrabbitsonthelist。Thesevenlargelop—earedrabbits，onanaverage，haveskulls4。11inchesinlength，and1136grainsincapacity;sothattheseskullshaveincreasedinlengthmorethanfivetimesasmuchastheskullsofthesixsmallwildrabbitshavedecreasedinlength;hencewemighthaveexpectedthattheskullsofthelargelop—earedrabbitswouldhaveincreasedincapacityfivetimesasmuchastheskullsofthesixsmallrabbitshavedecreasedincapacity;andthiswouldhavegivenanaverageincreasedcapacityof455grains，whilsttherealaverageincreaseisonly155grains。Again，thelargelop—earedrabbitshavebodiesofnearlythesameweightandsizeasthecommonhare，buttheirheadsarelonger;
consequently，ifthelop—earedrabbitshadbeenwild，itmighthavebeenexpectedthattheirskullswouldhavehadnearlythesamecapacityasthatoftheskullofthehare。Butthisisfarfrombeingthecase;fortheaveragecapacityofthetwohare—skulls（Nos。23，24）issomuchlargerthantheaveragecapacityofthesevenlop—earedskulls，thatthelatterwouldhavetobeincreased21percenttocomeuptothestandardofthehare。（4/23。Thisstandardisapparentlyconsiderablytoolow，forDr。
Crisp（’Proc。Zoolog。Soc。’1861page86）gives210grainsastheactualweightofthebrainofaharewhichweighed7pounds，and125grainsastheweightofthebrainofarabbitwhichweighed3pounds5ounces，thatis，thesameweightastherabbitNo。1inmylist。NowthecontentsoftheskullofrabbitNo。1inshotisinmytable972grains;andaccordingtoDr。Crisp’sratioof125to210，theskullofthehareoughttohavecontained1632grainsofshot，insteadofonly（inthelargesthareinmytable）1455grains。）
Ihavepreviouslyremarkedthat，ifwehadpossessedmanydomesticrabbitsofthesameaveragesizewiththewildrabbit，itwouldhavebeeneasytocomparethecapacityoftheirskulls。NowtheHimalayan，Moscow，andAngorarabbits（Nos。11，12，13ofTable3）areonlyalittlelargerinbodyandhaveskullsonlyalittlelonger，thanthewildanimal，andweseethattheactualcapacityoftheirskullsislessthaninthewildanimal，andconsiderablylessbycalculation（column7），accordingtothedifferenceinthelengthoftheirskulls。Thenarrownessofthebrain—caseinthesethreerabbitscouldbeplainlyseenandprovedbyexternalmeasurement。TheChinchillarabbit（No。14）isaconsiderablylargeranimalthanthewildrabbit，yetthecapacityofitsskullonlyslightlyexceedsthatofthewildrabbit。TheAngorarabbit，No。13，offersthemostremarkablecase;
thisanimalinitspurewhitecolourandlengthofsilkyfurbearsthestampoflongdomesticity。Ithasaconsiderablylongerheadandbodythanthewildrabbit，buttheactualcapacityofitsskullislessthanthatofeventhelittlewildPortoSantorabbits。Bythestandardofthelengthofskullthecapacity（seecolumn7）isonlyhalfofwhatitoughttohavebeen！Ikeptthisindividualanimalalive，anditwasnotunhealthynoridiotic。ThiscaseoftheAngorarabbitsomuchsurprisedme，thatI
repeatedallthemeasurementsandfoundthemcorrect。IhavealsocomparedthecapacityoftheskulloftheAngorawiththatofthewildrabbitbyotherstandards，namely，bythelengthandweightofthebody，andbytheweightofthelimb—bones;butbyallthesestandardsthebrainappearstobemuchtoosmall，thoughinalessdegreewhenthestandardofthelimb—
boneswasused;andthislattercircumstancemayprobablybeaccountedforbythelimbsofthisancientlydomesticatedbreedhavingbecomemuchreducedinweight，fromitslong—continuedinactivelife。HenceIinferthatintheAngorabreed，whichissaidtodifferfromotherbreedsinbeingquieterandmoresocial，thecapacityoftheskullhasreallyundergonearemarkableamountofreduction。]
Fromtheseveralfactsabovegiven，——namely，firstly，thattheactualcapacityoftheskullintheHimalayan，Moscow，andAngorabreeds，islessthaninthewildrabbit，thoughtheyareinalltheirdimensionsratherlargeranimals;secondly，thatthecapacityoftheskullofthelargelop—
earedrabbitshasnotbeenincreasedinnearlythesameratioasthecapacityoftheskullofthesmallerwildrabbitshasbeendecreased;andthirdly，thatthecapacityoftheskullinthesesamelargelop—earedrabbitsisveryinferiortothatofthehare，ananimalofnearlythesamesize，——Iconclude，notwithstandingtheremarkabledifferencesincapacityintheskullsofthesmallPortoSantorabbits，andlikewiseinthelargelop—earedkinds，thatinalllong—domesticatedrabbitsthebrainhaseitherbynomeansincreasedindueproportionwiththeincreasedlengthoftheheadandincreasedsizeofthebody，orthatithasactuallydecreasedinsize，relativelytowhatwouldhaveoccurredhadtheseanimalslivedinastateofnature。Whenwerememberthatrabbits，fromhavingbeendomesticatedandcloselyconfinedduringmanygenerations，cannothaveexertedtheirintellect，instincts，senses，andvoluntarymovements，eitherinescapingfromvariousdangersorinsearchingforfood，wemayconcludethattheirbrainswillhavebeenfeeblyexercised，andconsequentlyhavesufferedindevelopment。Wethusseethatthemostimportantandcomplicatedorganinthewholeorganisationissubjecttothelawofdecreaseinsizefromdisuse。
Finally，letussumupthemoreimportantmodificationswhichdomesticrabbitshaveundergone，togetherwiththeircausesasfaraswecanobscurelyseethem。Bythesupplyofabundantandnutritiousfood，togetherwithlittleexercise，andbythecontinuedselectionoftheheaviestindividuals，theweightofthelargerbreedshasbeenmorethandoubled。
Thebonesofthelimbstakentogetherhaveincreasedinweight，indueproportionwiththeincreasedweightofbody，butthehindlegshaveincreasedlessthanthefrontlegs;butinlengththeyhavenotincreasedindueproportion，andthismayhavebeencausedbythewantofproperexercise。Withtheincreasedsizeofthebodythethirdcervicalhasassumedcharacterspropertothefourthcervicalvertebra;andtheeighthandninthdorsalvertebraehavesimilarlyassumedcharacterspropertothetenthandposteriorvertebrae。Theskullinthelargerbreedshasincreasedinlength，butnotindueproportionwiththeincreasedlengthofbody;thebrainhasnotdulyincreasedindimensions，orhasevenactuallydecreased，andconsequentlythebonycaseforthebrainhasremainednarrow，andbycorrelationhasaffectedthebonesofthefaceandtheentirelengthoftheskull。Theskullhasthusacquireditscharacteristicnarrowness。Fromunknowncausesthesupra—orbitalprocessofthefrontalbonesandthefreeendofthemalarboneshaveincreasedinbreadth;andinthelargerbreedstheoccipitalforamenisgenerallymuchlessdeeplynotchedthaninwildrabbits。Certainpartsofthescapulaandtheterminalsternalboneshavebecomehighlyvariableinshape。Theearshavebeenincreasedenormouslyinlengthandbreadththroughcontinuedselection;theirweight，conjoinedprobablywiththedisuseoftheirmuscles，hascausedthemtolopdownwards;andthishasaffectedthepositionandformofthebonyauditorymeatus;andthisagain，bycorrelation，thepositioninaslightdegreeofalmosteveryboneintheupperpartoftheskull，andeventhepositionofthecondylesofthelowerjaw。
CHAPTER1。V。
DOMESTICPIGEONS。
ENUMERATIONANDDESCRIPTIONOFTHESEVERALBREEDS。
INDIVIDUALVARIABILITY。
VARIATIONSOFAREMARKABLENATURE。
OSTEOLOGICALCHARACTERS:SKULL，LOWERJAW，NUMBEROFVERTEBRAE。
CORRELATIONOFGROWTH:TONGUEWITHBEAK;EYELIDSANDNOSTRILSWITHWATTLED
SKIN。
NUMBEROFWING—FEATHERS，ANDLENGTHOFWING。
COLOURANDDOWN。
WEBBEDANDFEATHEREDFEET。
ONTHEEFFECTSOFDISUSE。
LENGTHOFFEETINCORRELATIONWITHLENGTHOFBEAK。
LENGTHOFSTERNUM，SCAPULA，ANDFURCULUM。
LENGTHOFWINGS。
SUMMARYONTHEPOINTSOFDIFFERENCEINTHESEVERALBREEDS。
Ihavebeenledtostudydomesticpigeonswithparticularcare，becausetheevidencethatallthedomesticracesaredescendedfromoneknownsourceisfarclearerthanwithanyotherancientlydomesticatedanimal。Secondly，becausemanytreatisesinseverallanguages，someofthemold，havebeenwrittenonthepigeon，sothatweareenabledtotracethehistoryofseveralbreeds。Andlastly，because，fromcauseswhichwecanpartlyunderstand，theamountofvariationhasbeenextraordinarilygreat。Thedetailswilloftenbetediouslyminute;butnoonewhoreallywantstounderstandtheprogressofchangeindomesticanimals，andespeciallynoonewhohaskeptpigeonsandhasmarkedthegreatdifferencebetweenthebreedsandthetruenesswithwhichmostofthempropagatetheirkind，willdoubtthatthisminutenessisworthwhile。Notwithstandingtheclearevidencethatallthebreedsarethedescendantsofasinglespecies，I
couldnotpersuademyselfuntilsomeyearshadpassedthatthewholeamountofdifferencebetweenthem，hadarisensincemanfirstdomesticatedthewildrock—pigeon。
Ihavekeptaliveallthemostdistinctbreeds，whichIcouldprocureinEnglandorfromtheContinent;