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Show 126 DOMESTIC RABBITS. CHAP. IV. (No. 4) is interesting, as, though now wild, it is known to be descended from a domesticated breed, as is still shown by its peculiar colouring and longer body; ncvcrthclcr:;s the skull has r covered its normal length and full capacity. The next tlu·cc rabbits arc wild, but of smnJl size, and they all have skulls with slightly lessoned capacities. The three Porto Santo feral rabbits (Nos. 8 to 10) offer a perplexing case; their bodies arc greatly reduced in size, as in a lesser degree arc their skulls in length and in actual capacity, in comparison with the skulls of wild English rabbits. But when we compare the capacities of the skull in the three Porto Santo rabbits, we observe a surprising clifforonco, which docs not st.'tnd in any relation to tho slight difference in tho length of thc:iJ: skulls, nor, as I boliovo, to any difference in tho size of their bodies; but I neglected to weigh separately their bodies. I can harclly suppose that the medullary matter of the brain in those three rabbits, living under similar conditions, can clitlor as much as is indicated by tho proportional cl.ifforcncc of capacity in their skulls; nor do I know whether it is possible that one brain may contain considerably more fluid than another. llonce I can tru·ow no light on this case. Looking to the lower half of tho Table, which gl.vcs the measurements of domesticated rabbits, we sec that in all the capacity of the skull is less, but in very various cl grccs, than might have boon anticipated according to tbo length of their skulls, relatively to that of the wild rabbit No. l. In line 22 the average meo.surcmcnts of seven large lop-cared mbbits arc given. Now the question arises, has tho average capacity of tho skull in these seven large rabbits increased as much as might have been expected from their greatly increased size of body. W c may endeavour to answer this question in two ways: in the upper half of the Table we have measurements of tho skulls of six' smnll wild rabbits (Nos. 5 to 10), and we find that on an average tho skulls arc in length ·18 of an inch shorter, and in capacity 91 grains less, than tho average length and capacity of tho three fir, t wild rabbits on the list. The seven large lop-cared rabbits, on an average, have skulls 4·11 inches in length, and 1136 grains in capacity; so that these skulls have increased in length more than five t:iJncs as much as the skulls of tho six small wild rabbits have decreased in length ; hence we might have expected that the skulls of the large lop-cared rabbits wonld have increased in capacity five t:iJncs as much as the skulls of the six small rabbits have decreased in capacity; and this would have given an average increased capacity of 455 grains, whilst tho real average increase is only 155 grains. Again, the largo lop-oared rabbits have bodies of nearly the same weight and size as tho common hare, but their heads are longer; consequently, if the lop-eared rabbits had been wild, it might have been expected that their skulls would have had nearly tho same capacity as that of the skull of the hare. But this is far from being tho case; for the average capacity of tho two hare-skulls (Nos. 23, 24) is so much larger than tho average capacity of the seven lop-cared skulls, that tho latter would have to be increased 21 per cent. to come up to tho standard of the hare. 28 28 This standard is apparently considerably too low, for Dr. Crisp (' Proc. Zoolog. Soc.,' 1861, p. SG) gives 210 grains n.s tho actual weight of tho CHAP. IV. EFFECTS OF USE AND DISUSE. 127 ::/:~>l;"~~>+;-~~C?c::'C?Clj .,.,""" """~~Clj""":::; .......... g;~·~o· 00 lb' [oc F""'& t-t I ~S?: ~. ~~~~:::;~ I I a:.o o 0 ' · · · · · 6:. :::;~ .. ~§1' 1>:> 01001001 • • ~t:r ----·-~~----------------------------01---0-· -~-·--·-~-- -~~~L_~Jl:_ _____ l -.;J-.;J -:JO'> -.;J -.;J-.;J CljC~j I 00 ~~: ~ ~0 1-'00 ~: :::: Clj~ ~ 01~ l S'g, ~;-n·~!b' !il~':'.~ ~ s3P' s ~ [ ~ ~ ('!) 0 ~. ~~~ ':<l c:;;O'>~~OI"' ..... "'~-'Cljl-'1-' ..... ~ g,~ g_~g'~ 1>:>0-JH>--.;J~~g~gg~:::; 0'> -:Ji>:>i>:>I>:>CljC~j !:. oo..,gg~f;l ;g 0 OIWOOOI>:>OO ~ [g:oc;~ g !"i.E &~>£ ~01&.:-.;J~~~~~~~~ -.;J ..... ~O'>I>:>WW~ ~i <liH'f8 ;;g '0 :l .... E:t:F~;~. - : - - g: fllg - 0 l:ll:l g:'~t;;·OQ 2.~ I = CD .:J.: g:'-'1 §'o ..5 iS ~ 5'8 ;:;:o=:s-~'" ~ S' 8 8 !ZP' ~!f~:g.~ - - 0 ?~ I :: 1::':: ~:~< .:.~ !"'w ~~ e_& OQ CD ciQ' s· s·8 Erb:~ ~ ::» ~ ~ 8 o t:r'o o...., ~ &~ &~ § (\),. (1) t ~ |