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Show 208 DARWINISM CIIAP. which ha~ just that amount of irregular cu~vaturc that is seen in dry and withered leaves .. T_h~ colour 1s very r~markablc fol' its extreme amount of vanab1hty, fro~ deep re~dish-brown to olive or pale yellow, hardly two speCimens bemg exact~y l'k but all comincr within the range of colour of leaves m ~:ri~us stages of de~ay. Still more curious is the fact that the paler wings, which imitate leaves most decayed, . arc usually covered with small black dots, often ga~hcrcd 111 L~ circular groups, and so exactly resembling the ~mute fun g1 011 decaying leaves that it is hard at first to behove th at the insects themselves arc not attacked by some s~c~ f~n gn~. The concealment produced by this wonderful Im1tat10n IS most complete, and in Su~atra I _have often seen one enter t~ bush and then disappear hke mag1c. Once I was so fortun n.t as to see the exact spot on which the insect settled ; but even then I lost si crht of it for some time, and only after a per-sistent search bd.is covered that 1. t was c1 o se bef m' e my eyes. l Here we have a kind of imitation, which is very common in a less developed form, carried to extreme perfection, ~ith the result that the species is very abundant over a considerable area of country. Protective Resemblance arnong Marine Anin,als. Amoncr marine animals this form of protection is very common. 5 Professor Moseley tells us that all the inhabi tants of the Gulf-weed are most remarkably coloured, for purposes of protection and conccalme~t, exactly l~kc the weed itself. "The shrimps and crabs whiCh swarm m the weed arc _of exactly the same shade of yellow ai5 the weed, and have w~n lc markings upon their bodies to rcprese.nt t?c _Patches of Mombranipora. The small fish, Antennarms, IS 1~ the same '~ay weed-colour with white spots. Even a Planarmn worm, wh1ch lives in the weed, is similarly yellow-coloured, and also a mollusc, Scyllrea pelagica." The same writer tells us that " a number of little crabs found clinging to the floats of the bl~wshclled mollusc, Ianthina, were all coloured of a corrcspondmg blue for concealment."2 1 Wallace's .Malay Archip elago, vol. i. p. 204 (fifth edition, p. 1 30), with figure. 2 Moseley's Kates by a N atw·alist on the Challenge?'. VII[ ORWIN AND US E~ OF 'OLOUR IN ANIMALS 209 Professor E. ~ '. Morse of ~ 'alcm, Ma. s., found that most of the N ?w En~lmul ma,rinc molln. C<L were protectively coloured ; 1n stanc1ng among others a li ttle red chi ton on r ocks ~lothc~l ,_vith red calcareous rdgrc, and Cr piduln, pl:tna, livmg Wlthlll t he npcr tlll'Ci> of Lh ' shells of hu·gcr sp 'cic: of Ga.s~cropod s . :tlHl o.f a pmc_ whi~-c . colonr corrc. p() nding to its h<tbi_tat, wlule all JCcl sp '<.;1 s h vmg on , caw cd or o11 the out. Jdc of chrk shells were dark hrown.l A i>till more interesting caso h:ts hccn reco rd ed by Mr. George Brady. He says: "Amongst th e Nnlliporc which m < ~ tlc( L too·eth r the laminari:t root. .; in Lh c Firlh of Clyde were livin o·bmtmcrous sm:Lll. starfishes (Ophio ·om :~ hell is) which, except bwhcn their wnthmg movement. betr:Lyccl them, wore qnitc undistingJtishablc from tl~o calcarcon. hran chcs of the a]g;t; th eir r igid an gularly twisted rays had all t he appearance of the coralline and exactly n ... _imilatcd to its clark purple colom, so that thowrh I hchl m my hand a root in which were half a dozen of the stnrfi shcs, I was r eally unable to detect them until revealed hy their movcmcnts."2 · These ~e w cxa.mpl.cs arc snffi cicnt to show that the principle of protcct1 vc colomt ton extends to the ocean as w 11 as over the earth ; an:l if we consider how completely ignoran t we arc of the hahtts ancl SUJ'l'Onnclings of most marine nnimals, it mar well happen that many of the colours of tropical fi shes, whiCh ~cern Lo . ns so stntngc and so conspicuon., arc really pr?t?ct1vc, owmg to the number of equally strange and bnlhant forms of corals, sea-anemones, sponges, and seaweeds among which they live. Protection by Te?Tifying Enernies. A consi lcrablc number of qui to cl fenceless insects obtain protection from some of their enemies by having acquired a resemblance to langerous animals, or by some threatenin g or t~nusual appearance. This is obtained either by a modifi cat~ on of shape, of habits, of colour, or of all combined. The simplest form of this protection is the acroTessivc attitude of the caterpillars of the Sphingic.lro, the f~;cpart of the body 1 Proceedings oj' the Bo<;lon Sue. of Nat. JJisC., vol. xiv. 1871 . ~ N uture, 1870, p. 376. p |
