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their peculiarities not easily understood by any but ornithologists, it will be better to consider the series of fifty families of Passeres as one compact group, and endeavour to point out what external peculiarities are most distinctive of those which inhabit tropical countries.
Owing to the prevalence of forests and the abundance of flowers, fruits, and insects, tropical and especially equatorial birds have become largely adapted to these kinds of food ; while the seed-eaters, which abound in temperate lands where grasses cover much of the surface, are proportionately scarce. Many of the peculiarly tropical families are therefore either true insect-caters or true fruit-eaters, whereas in the temperate zones a mixed diet is more general.
One of the features of tropical birds that will first strike the observer, is the prevalence of crests and of ornamental plumage in various parts of the body, and especially of extremely long or curiously shaped feathers in the tails, tail-coverts, or wings of a variety of species. As examples we may refer to the red paradise-bird, whose middle tail-feathers are like long ribands of whalebone; to the wire-like tail-feathers of the king bird-of-paradise of New Guinea, and of the wire-tailed manakin of the Amazons; and to the long waving tail-plumes of the whydah finch of West Africa and paradise-flycatcher of India; to the varied and elegant crests of the cock-of-the-rock, the king-tyrant, the umbrella-bird, and the six-plumed bird-of-paradise ; and to the wonderful side-plumes of most of the true paradise-birds. In other orders of birds we have such remarkable examples as the racquet-tailed kingfishers of the Moluccas, and the racquet-tailed parrots of
Celebes ; the enormously developed tail-coverts of the peacock and the Mexican trogon; and the excessive wing-plumes of the argus-pheasant of Malacca and the long-shafted goatsucker of West Africa.
Still more remarkable are the varied styles of coloration in the birils of tropical forests, which rarely or never appear in those of temperate lands. We have intensely lustrous metallic plumage in the jacamars, troyons, humming-birils, sun-birls, and paradisc-birils; as well as in some starlings, pittas or ground thrushes, and drongoshrikes. Pure groen tints occur in parrots, pigeons, green bulbuls, greenlets, and in some tanagers, finches, chatterers, and pittas. These undoubtedly tend to concealment; but we have also the strange phenomenon of white forest-birils in the tropics, a colour only found elsewhere among the aquatic tribes and in the arctic regions. Thus, we have the bell-bird of South America, the white pigeons and cockatoos of the East, with a few starlings, woodpeckers, kingfishers, and goatsuckers, which are either very light-coloured or in great part pure white.
But besides these strange, and new, and beautiful forms of biril-life, which we have attempted to indicate as characterising the tropical regions, the traveller will soon find that there are hosts of dull and dingy birils, not one whit different, so far as colour is concerned, from the sparrow's, warblers, and thrushes of our northern climes. He vill however, if observant, soon note that most of these dull colours are protective; the groups to which they belong frequenting low thickets, or the ground, or the trunks of trees. He will find groups of birds specially a lapted to certain modes of tropical life.
Some live on ants upon the ground, others peck minuto insects from the bark of trees; one group will devour bees and wasps, others prefer caterpillars; while a host of small birds seek for insects in the corollas of flowers. The air, the carth, the undergrowth, the tree trunks, the flowers, and the fruits, all support their specially adapted tribes of birils. Each species fills a place in nature, and can only continue to cxist so long as that place is open to it; and each has become what it is in every detail of form, size, structure, and even of colour, lerause it has inherited through countless ancestral forms all those variations which have best adapted it almong its fellows to fill that place, and to leave behind it equally well adaptel successors.
Reptiles and Amphibia.- Next to the birds, or perhaps to the less observant cye even before them, the abundance and variety of reptiles form the chief characteristic of tropical nature; and the three groupsLizards, Snakes, and Frogs, comprise all that, from our present point of view, need be noticed.
Lizards.--Lizarils are by far the most abundant in individuals and the most conspicuous; and they constitute one of the first attractions to the visitor from colder lands. They literally swarm everywhere. In cities they may be seen running along walls and up palings; sumuing themselves on logs of woodl, or creeping up to the caves of cottages. In every garden, roail, or dry sandy patlı, they scamper aside as you walk along. They crawl up trees, keeping at the further side of the trunk and watching the passer-by with the caution of a squirrel. Some will walk up smooth walls with the greatest ease; while in houses the various kinds of Geckos
cling to the ceilings, along which they run back downwards in pursuit of flics, holding on by means of their dilated toes with suctorial discs; though sometimes, losing hold, they fall upon the table or on the upturned face of the visitor. In the forests large, flat, and marbled Geckos cling to the smooth trunks; small and active lizards rest on the foliage; while occasionally the larges kinds, three or four feet long, rustle heavily as they move among the fallen leaves.
Their colours vary much, but are usually in harmony with their surroundings and habits. Those that climb about walls and rocks are stone-coloured, and sometimes nearly black; the house lizards are grey or prale-ashy, and are hardly visible on a palm-leaf thatch, or even on a white-washed ceiling. In the forest they are often mottled with ashy:green, like lichen-grown bark. Most of the ground-lizards are yellowish or brown; but some are of beautiful green colours, with very long and slender tails. These are among the most active and lively; and instead of crawling on their bellies like many lizards, they stand well upon their feet and scamper about with the agility and vivacity of kittens. Their tails are very brittle ; a slight blow causing them to snap off, when a new one grows, which is, however, not so perfectly formed and completely scaled as the original member. It is not uncommon, when a tail is half broken, for a new one to grow out of the wound, producing the curious phenomenon of a forked tail. There are about 1,300 different kinds of lizards known, the great majority of which inhabit the tropics, and they probably increase in numbers towards the equator. A rich vegetation and a due proportion of moisture and sunshine scem favourable
to them, as shown by their great abundance and their varieel kinds it Para and in the Aru Islands-.places which are nearly the antipodes of each other, but which buth enjoy the fine equatorial climate in perfection, and ile alike pre-eminent in the variety and beauty of their insect life.
Three peculiar forms of lizard may be mentioned as specially characteristic of the American, African, au Asiatic tropical zones respectively. The iguanas of South America are large arboreal herbivorous lizards of a beautiful green colour, which renders them almost invisible when resting quietly among foliage. They are distinguished by the serrated back, deep dew-lap,
und enormously long tail, and are one of the few kinds of lizarils whose flesh is consiilered a delicacy. The chameleons of Africa are also arboreal lizards, and they have the prehensile tail which is more usually found among American animals. They are excessively slow in their motions, and are pretucted by the wonderful power of changing their colour so as to assimilate it with that of immediately surrounding oljects. Like the majority of lizards they are insectivorous, but they are said to be able to live for monthis without taking food. The dragons or flying lizarils of India and the larger Malay islanıls, are perhips the most curious and interesting of living reptiles, owing to their power of passing through the air by means of wing-like membranes, which stretch along cach side of the boily and are expanded by means of slender bony processes from the first six false ribs. These membranes are foleled up close to the body when not in use, and are then almost imperceptible ; but when open they form a nearly circular well, the upper surface