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Show CnaP.lV. DOMES'I'1C RABlllTS. 128 d many domestic . ·ked that, if we had lJossoss~ ·t would l1avo I have preVIously rom~rrro size with tho wild. rn.bhJt, ~he Himn.ln.yn.n, rn.bbits of tho F>aruc avtcltoabc"p"city of their sknlls. lNlo)'v "l'C only a little t compare 1 '" •• 13 f Ta l c •• · . boon easy o . "Lbhits (Nos. 11, 12, o than tho wild ammal, 1\ioscow, ancl Angora. I· skulls only a little longer,. l ' than in tho wi ld l·n·ger in body, an<l ]utvc . ··ty of their skulls JR css , ·d'nrr to the ' tl t tho actual capac1 . ( 1 ron 7), accm 1 ,.., and we ROC . 1 ta ·a ~ l,ly loss by calculatiOn co u s of tho brain-caHo ld comn emu . Tho nauowncs. anunn. ' ar . 1 1 'lln'th of' their skulls. , l by extcmn.l Jl1C:1Hlll'C-diffcronco m t 1~1 ~s ~ould be plainly soon and P.~v·c~ly larger animal t haH in t~cso ~;ll~C~~c;~illa mbbit (~o. 141).~s ~l~~lsJm~~; sliglttly cxccccls thlfltt men . . . ot tho capaClty o l s • . . •rs tlto most rcm:wlm ) o th(o WJl~ rabllJbt,.ty 'Tho Angorn,rabbit, No. 10, oltle . tl of silky fm hcan; . tl w1 ld rab 1 • . 1 u ancl eng 1 L L o ,1 .0 thi. s am.r oal m. J·t·s j)lUO wlutIc cho ot a conslC'l e t.a ~Ll Jy longer hcac am cn.sc' . . Jon domesticity. .t as ·t of its skn II is Joss tlmn tho stn.mp of 'I~ ·abbit but tho actual capa?J y )~ tho standard of tlJO body ~~1~~::ct~~ Ji:tlo wild Porto Sant~ r;b~~t~uly ~alf 0'r wlutt it ought ~;:~th of skull the capacity~"~ coll::ma? alive, ,,u it was 'Cot unhaa:;l'; ]b boon' J kept tlus m VI ua bb't so much sm·pnscd m ' ta to u·wrc · f tl: Angora ra J • I 1 lso t'c This case o 10 l tl om correct. lave a. ~o~· l~:tcld. all tho mcasUl'omcnts and Jo~:~ A~gora with that of tho " ·ild cormepp ared tllc capacity of tho s1k ulbl yo t h o l en gtll "•• nd weight of thho bho .J .y· , r·1bl,it by other stanclards~ name y, . but by all those standards t o ram • d by tho weight of tho limb-bonos 'h . loss dem·co wucn tho standarcl of aanpp ears to be roue1 1 t oo sm all ' thohuisg lamtt ear circum"' Rtanco may p rob·:t,bly be L • tho limb-bonos was u ~d; an~ ~hi anciently domesticated ~rood. havlJ~g untcd for by tho hmbs o. s 't long-continued mactlve 1 c. acco much reduced in wCJght, f-rom 1 s . l i said to differ from other ~I ~~:c I infer that in tho Ang~ra. hr.e~\l:~~~a~ity of tho skull has really . . uictor and mOic soCia ' broods m bcmg q 1 bl amount of reduction. undergone a rcmar ca o . namely firstly, that the -From the several facts above. givtben,-lii'malay~n Moscow, an.d · f th skull m e ' ' ' actual capacity o e 1 . th wild rabbit, though they are An()'ora breeds, is less tlan m e . l . secondly that the b . tl . laraer amma s ' ' in all their dimensiOns ra 1Cr b , . d abbits has not been car)acity of the skull of the largte.lop-otahioo carpaoity of the skull of increased m· near· 1 y the. same rba 10 ads ·eased. and tlu·r rlly, t h at the smaller wild rabbits has oen ecr l · e' lop-eared rabbits h k 11 in these same aig the capacity of t o s u . al of nearly the same is very inferior to that of the bare, an amm . b . . of a hare which weighed 7lbs., . anmdm 1 25 graiHs as the WC·I ·""' ht of the brain of a rabbit which wOI.ghed 31bs. 5 that is tho same wUlght as tho ra~~it No.1 in my list. Now th.o conlents of tl.le skull of rabbit No. 1 111 shot 1 n72 rains . anu ac ·onlis in my tn,b 0 " ~ ' 210 tho ing to Dr Crisp'~ rrtho of 125 to . : d ] 11 f ti o hare ou n·h t to have con tam~ s ru o t b . t. u or only (In 1G32 grains of ~ho.L, ms ca table) H55 the largest lmro m my gmins. CHAP. IV. EFFECTS OF USE AND DISUSE. 129 size,-I conclude, notwithstanding tho remarkable differences in capacity in the skulls of the small P. Santo rabbits, and likewise in the large lop-cared kinds, that in all long-domesticated rabbits the brain has either by no means increased in due proportion with the increased length of the head and increased size of the body, or that it has actually decreased in size, relatively to what would have occurred had these animals lived in a state of nature. When we remember that rabbits, from having been domesticated and closely confined during many generations, cannot havo exerted their intellect, instincts, senses, and voluntary movements, either in escaping from various dangers or in searching for food, we may conclude that their brains will have been feebly exercised, and consequently have suffered in development. We thus see that the most important and complicated organ in the whole organization is subject to the law of decrease in size from disuse. Finally, let us sum up the more important modifications which domestic rabbits have undergone, together with their causes as far as we can obscurely see them. By the supply of abundant and nutritious food, together with little exercise, and by the continued selection of the heaviest individuals, the weight of the larger breeds has been more than doubled. The bones of the limbs have increased in weight (but the hind legs less than the front legs), in due proportion with the increased weight of body; but in length they have not increased .in due proportion, and this may have been caused by the want of proper exercise. With tho increased size of the body the third cervical vertebra has assumed characters proper to the fourth cervical ; and the eighth and ninth dorsal vertebrro have similarly assumed chaI'acters proper to the tenth and posterior vertebrre. The skull in the larger breeds has increased in length, but not in due proportion with the increased length of body; the brain has not duly increased in dimensions, or has even actually decreased, and consequently the bony case for tho brain has remained narrow, and by cono1ation has affected the bones of the face and the entire length of the skull. The skull has thus acquired its characteristic nanowness. From unknown causes the supraorbital processes of the fmntal bones and tho free end of the malar bonos havo increased in breadth; and in the larger breeds VOL, I. K |