Page:Encyclopædia Britannica, Ninth Edition, v. 1.djvu/726

Rh 684 lishment to have disappeared. One remarkable feature is the abundance of horses, which is such that North America may be regarded as the land of horses during the Pliocene and Post-Pliocene period. tf. Ame- The existing mammals of North America must now be ica : considered. We can only refer to a few of the more con- vlammalia. S pi cuous species here. South America has numerous families peculiar to itself, but North America has none which are not also represented in South America. There are numerous representatives of the Canidce or dog family, such as the prairie, Mexican, and maned wolves, and several foxes, of which the Arctic, common American, cross, and silver foxes are of high commercial value on account of their furs. Amongst the cats are three or four species of lynx, which afford valuable furs. The beaver, though abundant in some places, is, like the bison, fast diminish ing before the encroaching steps of the colonists. The grizzly, the black, and the polar bears are common in the more mountainous and colder regions of the continent, and are much hunted by the fur traders. Racoons and Vir ginian opossums are prevalent in the south portion of the United States. The Rocky Mountain goat reigns supreme amidst the rocks in inaccessible fastnesses of the llocky Mountain range; while the rein-deer, the elk, and the wapiti give a character to the mammalian fauna of the more level districts. Further details respecting the mammals of North America will be found under the names of the separate countries; and those who wish for still fuller information may consult the works of Lord, Small, Miiller, Harlan, and Allen on the mammals of various regions, The Quadrupeds of North America by Audubon and Bachman, the articles by Gilpin in the publications of the Institute of Natural Science at Halifax, Adams Field and Forest Rambles, TJie. North-West Passage by Viscount Milton and Dr Cheadle, Morgan s work on the Beaver, and the nume rous reports issued by exploration expeditions. Birds. The birds of America are very numerous in almost every great family. The researches of Wilson, Charles Lucien Bonaparte, Audubon, Richardson, Dekay, Blakiston, Cassin, Gundlach, Lord Lawrence, Sclater, Salvin, and Baird, have beautifully illustrated the ornithology of North America ; while those of Azara, Humboldt, Swainson, Waterton, Edmonstone, Darwin, Landbeck, Philippi, Cassin, &amp;lt;fcc., have thrown great light on that of South America. The North American species of birds already described amount to nearly 700 ; the species of South America are over 2300 ; so that we may fairly estimate the ornithology of America to include upwards of 3000 species. The fossil remains deserve particular notice. It is very probable that the footprints on the older secondary rocks of North America arc those of birds. A large number of remarkable genera found in the Cretaceous rocks have recently been described by Professor Marsh and others. Ophidia. The serpents of America are very numerous, and in clude amongst others, the following genera : Tortrix, Calamaria, Coronella, Xenodon, Heterodon, Lycodon, Coluber, Herpetodryas,Psammophis, Dendrophis, Dryophis, Dipsas, Tropidonotus, Homalopsis, Boa, Elaps, Trigono- cephalus, Crotalus. Of these the genera Heterodon and Crotalus or rattle snake are entirely peculiar to America, and the latter are by far the most deadly of serpents. The reptilia of North America have been well described by Dekay and Hol brooke. The North American saurians belong to the genera Crocodile, Alligator, Anolis, Skink, Agama, Tropidolepis, Ophisaurus, Leptophis. Of the Ranidae there are Rana, Bufo, and Hyla. The North American and Asiatic regions form a zoological kingdom, according to Dr Strauch, which is characterised [ZOOLOGY. by the prevalence of Emydes and by the presence of Trionychides. In the North American region there are 44 species distributed over four sub-regions viz., the north west part, which lies west of the Rocky Mountains ; the north-east part, which lies east of them; the south-east part and the south-west part, which embraces Central America. South America and Australia together form another king dom, characterised by the prevalence of Chelydes, and the total absence of Trionychides. There are about 35 species in the Soiith American region. The multitude of fishes in South America is extraordinary, Fishes, and still more so is the marvel] uus variety of form which they exhibit. A large number of species have very circum scribed ranges, so that not only does each river basin have a distinct fauna, but a number of distinct faunas occupy different portions of the same river, as is well exemplified in the Amazons, Tocantins, Rio Negro, and other rivers, where most of the fishes at stations a few hundred miles apart are for the most part specifically distinct. Professor Agassiz, in his scientific journey through Brazil, collected about 2000 species from the Amazon basin only. In fishes, as in other classes, there is a remarkable difference between the faunas of North and South America, and in this class also North America has much in common with Europe and North Asia. The sturgeons abound in North America, but are absent in South America, where the corre sponding group is theGoniodonts; theSiluroids are abundant in both portions of the continent ; the perches are numerous throughout North America, but none occur in South America, where, however, they are represented by the Chromids. The Cyprinoids are abundant in North America, but absent in South America, where we have the allied group of Cyprinodonts. The Characines of South America represent the Salmonidce of North America, each group being confined to its own portion of the continent. There are several other small families present in South America, such as the Erythrinoids, Gymnotines, and others. In the meagre outline of American vegetation which it Botany is possible to attempt here, Ave shall more or less strictly adhere to the principle laid down by Schouw, viz., that in constituting a botanical region, at least one-half of the species and one-fourth of the genera should be peculiar to it. We shall therefore divide the horizontal range of the vast continent into zones, commencing with the Arctic, and proceeding towards the Antarctic Circle. In the Arctic Region or Region of Saxifragacece, as near to the Pole as man has yet penetrated, is found the red snow plant (Protococcus nivalis), penetrating the snow itself, sometimes to the depth of 12 feet, and covering for miles with its crimson tints the cliffs and ice-floes of the Polar Sea. Greenland is botanically distinguishable from Arctic America proper, inasmuch as it produces heath (Calluna vidgaris), which, it is somewhat remark able, is nowhere to be found on the continent. The most remarkable of the sub-arctic lichens is that known as Tripe de Roche, which has often preserved the lives of famished &quot; trappers,&quot; who, but for its sustenance, must have perished of hunger. The Saxifrages which dis tinguish this region vary in species, and sometimes in genera, from those of Europe, but, generally speaking,, there is a strong resemblance, which amounts almost to- identity, as the Arctic shores are approached. Emerging from the region of Saxifragacece, we find 1 ourselves in that of the Asters and Solidagos, extending to&amp;gt; the parallel of 36&quot; N. This region not only produces many species of aster and solidago, but also a great variety of oaks and firs, and numerous species of Vaccinium.. Among the oaks of Canada and the United States are, thet lime oak (Quercus virens),ihe laurel oak (Quercus laurifolia}^ the black oak (Quercus tinrtoria], the white or iron oak