toral fins. Pterodactylus, by its large and pointed wings, retractile neck and snapping long-toothed jaws, seems to realize all that can be supposed of a reptile accustomed to flap the air rather heavily not far above shallow waters, and occasionally to snatch from them fishes swimming near enough to the surface to come within reach. Life in Trees presents us with a considerable variety of contrivances for holding to the surface, grasping the branches, or making incisions into the bark and wood. To say nothing of the sucker feet of Dipterous Insects, and the Gecko Lizard, we may remark on the prevalent idea of climbing and holding on by opposable fingers which appear among the Reptilia in Chameleon, among the Birds in the Parrot and Woodpecker, and among the Mammalia in the whole race of the Quadrumana. Perhaps the prehensile tail of the Platyrhine Monkeys, and the suspensorial claws of the Sloth, may be quoted among the singular provisions of animals of the New World. It is even more curious to notice with respect to some of these climbing animals, the other adjustments which complete their equipment. Thus the feeding of the Woodpecker is provided for not only by its scansorial foot, its supporting tail, and its perforating beak, which makes the forests ring around. We have further to notice the singular * piece of mechanism by which its long tongue is suddenly projected, and suddenly retracted, a mechanism of elastic bone, the hyoid or tongue-bone greatly lengthened backward, the horns turned upward in a groove of the cranium and planted in the right nostril. Inexplicable on any view but that of a wise co-ordination of the different parts of the structure to answer an appointed end. With this view in our minds we no longer wonder at the long spirally wrapped muscles which govern this elastic bone, or at the terminal armature of the tongue. Nor under such an aspect are we confounded by the sudden outrush of the Chameleon's tongue, which seizes instantly, by its moistened extremity, the fly so patiently watched; the result of a combined mechanism whereby the soft mass is straightened, directed, and shot forth like an arrow flying to its mark, and then retracted and folded within the jaws which otherwise could not have received it1. Life on land presents no less variety of appropriate adjustments, by which the general types of the Vertebrata and Articulata are made to answer a great diversity of requirements. To take examples from Mammalia. For pure motion what can be conceived more complete than the whole frame, and especially the unidigital limbs of the horse? The predaceous habits of the Feline races are indicated by their sharp curved claws, retractile into sheaths; the Mole is strengthened for digging by the approximation of the scapulæ, and the outward-turned broad anterior feet; even for suspension during hybernation the Bat has a hooked finger prepared; and thus, to close this part of the subject, we find everywhere in rich profusion, what would be regarded as remarkable inventions, if they were due to human minds and hands, and which cannot be removed from the list of intelligent adaptations because they are frequent in nature, and are of higher perfection and greater beauty than any work of man. 1 These peculiarities of the Woodpecker and Chamæleon and other animals were some of my pleasant studies of Natural History 30 years since. On the whole it is evident that in the several great types of animals very similar mechanical functions are performed by means of organizations which depend on the type, and have only analogical resemblances in the different types. In each great type the variations of the several organs may be such that, while the homologies are not to be doubted, the employment of the organs varies much. In some cases parts of the fabric dwindle to mere representatives, as the wing-bones of the Ostrich and the pelvic bones of the Whale; in others they die out altogether, as the hind-limbs of the Cetacea. These gradations and modifications of the parts constituting a general type may be represented by one of three suppositions: -First, that the structure is what we see because that portion of the general type, and that state of the organ or constituent part of the type was selected as suitable for the life of the creature; Secondly, that the structure has become what it is by degradation from a fuller type through the reduction or suppression of certain parts by want of exercise of their functions; Thirdly, that the typical structure is incompletely manifested because some of the functions have been unexercised, and the organs which belong to them consequently remain undeveloped. Each of these views may be thought to be so far founded on observation of nature as to be allowed in an hypothesis for comparison with more observations. The choice between them can only be justified by reference to phenomena, which by their number, consistency and critical character, may furnish a basis for sound judgment. Without such reference a choice no doubt will be often made, but it can then be little better than prejudice, and must be expected to differ in different persons, according to the previous training of their minds. It is consoling to believe that each may be connected, indeed will be connected, by minds accustomed To look through Nature up to Nature's God, with reverential thoughts of the GREAT MAKER. No sincere inquirer for truth will be likely to expect success in the search, unde queat res quæque creari, Et quo quæque modo fiant, operâ sine Divōm; and no one who has advanced so far in Philosophy as to have thought of one thing in relation to another will ever be satisfied with Laws which had no Author, Works which had no Maker, Co-ordinations which had no Designer. In this as in other cases, An undevout philosopher is mad. SYSTEM OF LIFE COEVAL WITH MAN. The Living creation then, as we see it, is found to exist only in a fabric of certain sorts and certain combinations of matter, in the presence of the atmosphere, subject to continual loss and restoration of parts, suffering death in every individual, and renewed by birth of other individuals; adapted to the elements of water, land, and air; limited by temperature and physical conditions; called into being at certain points of origin, and spread over certain areas of occupation. Thus the visible creation presents itself as a cal |