_Plate XVIII. Illustrative of the Zoology of California and the Rocky Mountains._--We have chosen for the subject of this illustration, the peculiar Birds of the Western mountains. The two birds in the foreground are a species of grouse (_Pediocætes Columbianus_), entirely confined to this sub-region; while the only other species of the genus is found in the prairies north and west of Wisconsin, so that the group is peculiar to northern and western America. The crested birds in the middle of the picture (_Oreortyx picta_), are partridges, belonging to the American sub-family Odontophorinæ. This is the only species of the genus which is confined to California and Oregon. The bird at the top is the blue crow (_Gymnokitta cyanocephala_), confined to the Rocky Mountains and Sierra Nevada from New Mexico and Arizona northwards, and more properly belonging to the Central sub-region. It is allied to the European nutcracker; but according to the American ornithologist, Dr. Coues, has also resemblances to the jays, and certainly forms a distinct genus. The grizzly bear (_Ursus ferox_) in the background, is one of the characteristic animals of the Californian highlands. Plate XVIII. [Illustration] SCENE IN CALIFORNIA, WITH SOME CHARACTERISTIC BIRDS. {129}_II. The Central, or Rocky Mountain Sub-region._ This extensive district is, for the greater part of its extent, from 2,000 to 5,000 feet above the sea, and is excessively arid; and, except in the immediate vicinity of streams and on some of the higher slopes of the mountains, is almost wholly treeless. Its zoology is therefore peculiar. Many of the most characteristic genera and families of the Eastern States are absent; while a number of curious desert and alpine forms give it a character of its own, and render it very interesting to the naturalist. _Mammalia._--The remarkable prong-horned antelope (_Antilocapra_), the mountain goat (_Aplocerus_), the mountain sheep or bighorn (_Ovis montana_), and the prairie-dog (_Cynomys_), one of the Rodentia, are peculiar to this sub-region; while the family of the Saccomyidæ, or pouched rats, is represented by many forms and is very characteristic. Here is also the chief home of the bison. The glutton (_Gulo_) and marmot (_Lagomys_) enter it from the north; while it has the racoon (_Procyon_), flying squirrel (_Sciuropterus_), ground squirrel (_Tamias_), pouched marmot (_Spermophilus_) and jumping mouse (_Jaculus_) in common with the countries east or west of it.