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Show MORPHOLOGY. [OBAP. XIII. 378 We never find, for instance, the bones of the arm and forearn1 or of the thigh and leg, transposed. l-Ienee the sa1ne n~mes can he given to the homologous bones in widely different animals. We see !he same great law in the construction of the mouths of Insects. : what can be more different than the immensely long spiral proboscis of a sphinx-moth, the curious folded one of a bee or bug, and the great jaws of a beetle ~-yet all these organs, serving for such different purposes, arc formed by infinitely numerous modifications of an upper lip, 1nandibles, and two pairs of maxillre. Analogous laws govern the construction of the mouths and limbs of crustaceans. So it is with the flowers of plants. . Nothing can be more hopeless than to attempt to ex-plain this similarity of pattern in members of the same class, by utility or by the doctrine of final causes. The hopelessness of the attempt has been expressly admitted by Owen in his most interesting work on the ' Nature of Limbs.' On the ordinary view of the independent creation of each being, we can only say that so it is ;-that it has so pleased the Creator to construct each animal and planTth. e explanation is manifest on the theory of the natural selection of successive slight modifications,-each modification being profitable in some way to the modified form, but often affecting by correlation of growth other parts of the organisation. In changes of this nature, there will be little or no tendency to modify the original pattern, or to transpose parts. The bones of a limb might be shortened and widened to any extent, and become gradually enveloped in thick membrane, so as to serve as a fin; or a webbed foot might have all its bones, or certain bones, lengthened to any extent, and the membrane connecting them increased to any extent, so as to serve as a wing: yet in all this great amount of modification there will be no tendency to alter the framework of bones or the relative connexion of the several parts. If we suppose that the ancient progenitor, the archetype as it may be called, of all mammals, had its lilnbs constructed on the existing general pattern, for whatever purpose they OBAP. XIII.) MORPHOLOGY. 379 served, we can at once per . h l 1 ce1 ve the 1 · · . . t e 101110 ogous construction of 1 ~ aln Slgnlficatlon of whole class. So ,vith the t le hmbs throughout the only to suppose that the'. mouths of insects, we have upper lip, mandibles and ~I com:non progenitor had an being perhaps very si~ple .w£ pau of Inaxillre, these parts tion will account for the in1flni~r~ ,; an~ th~n natural selecfunction of the mouths of . e lVersity In structure and conceivable that the generallns~~ts. Nevertheless, it is become so much obscured pa ern of an organ might atrophy and ultimately by th:~o~ ~e finally. lost, by the parts,. by the soldering together olo~~e abor~JOn of certain doubhng or multiplication of oth er pai~s, .and by the we know to be within the limit e:r;,-v~r1.a~1ons which paddles of the extinct i ant' s o ~osslblhty. In the mouths of certain suctori!J ~rus:~c:ca-b~hrds, and in the seems to have been thus to a t .ans, e general pattern There is another and cer ain e::ctent obscured. present subject. namely eq;hlly cuno~s branch of the same part in different ~e ; cofpanson not of the different parts or organs i~hC:ss 0 a. cl~s~, but of the physiologists believe that the b arne mllVldual. Most homologous with-that is cor. ones .o the skull are relative connection with-th llespond lin number and in number of vertebrre The 0 e ~menta parts of a certain each member of th~ verteb~~~enord and .posterior limbs in plainly homologous. We see ~han arhcula~e classes are the wonderfully complex jaws : s~~e la~ m comparing It is familiar to almost ever n egs .1n crustaceans. relative position of the s 1 y one, that m a flower the as well as their inf t epa s, petals, st:amens, and pistils yiew that they con~fs: ;f stru~ture; h'e mtelligible on th~ m a spire. In monstroume amoip osed leaves, arranged ~ence of the possibilit ;fplants, we ofte:n get direct evimto another . and Y one organ bmng transformed crustaceans a~d in m':e ca~h actua}ly see in embryonic that organs which h ny o er animals, and in flowers ent, are at :m early :ta: ~;tu;e ~~come extre~ely differ: How inex licabl giow exactly ahke. of creation ! p Why ~harellhfue bfac~s on the ordinary view . ou e raln be enclosed in a box |