_Plate XIX. Illustrative of the Zoology of the Central Plains or Prairies._--We here introduce four of the most characteristic mammalia of the great American plains or prairies, three of them being types confined to North America. The graceful animals on the left are the prong-horned antelopes (_Antilocapra americana_), whose small horns, though hollow like those of the antelopes, are shed annually like those of the deer. To the right we have the prairie-dogs of the trappers (_Cynomys ludovicianus_) which, as will be easily seen, are rodents, and allied to the marmots of the European Alps. Their burrows are numerous on the prairies, and the manner in which they perch {130}themselves on little mounds and gaze on intruders, is noticed by all travellers. On the left, in the foreground, is one of the extraordinary pouched rats of America (_Geomys bursarius_). These are burrowing animals, feeding on roots; and the mouth is, as it were, double, the outer portion very wide and hairy, behind which is the small inner mouth. Its use may be to keep out the earth from the mouth while the animal is gnawing roots. A mouth so constructed is found in no other animals but in these North American rats. In the distance is a herd of bisons (_Bison americanus_), the typical beast of the prairies. _Birds._--This sub-region has many peculiar forms of birds, both residents, and migrants from the south or north. Among the peculiar resident species we may probably reckon a dipper, (_Cinclus_); _Salpinctes_, one of the wrens; _Poospiza_, _Calamospiza_, genera of finches; _Picicorvus_, _Gymnokitta_, genera of the crow family; _Centrocercus_ and _Pediocætes_, genera of grouse. As winter migrants from the north it has _Leucosticte_ and _Plectrophanes_, genera of finches; _Perisoreus_, a genus of the crow family; _Picoides_, the Arctic woodpecker; and _Lagopus_, ptarmigan. Its summer migrants, many of which may be resident in the warmer districts, are more numerous. Such are, _Oreoscoptes_, a genus of thrushes; _Campylorhynchus_ and _Catherpes_, wrens; _Paroides_, one of the tits; _Phænopepla_, allied to the waxwing; _Embernagra_ and _Spermophila_, genera of finches; _Pyrocephalus_, one of the tyrant shrikes; _Callipepla_ and _Cyrtonyx_, American partridges. Besides these, the more widely spread genera, _Harporhynchus_, _Lophophanes_, _Carpodacus_, _Spizella_, and _Cyanocitta_, are characteristic of the central district, and two genera of humming-birds--_Atthis_ and _Selasphorus_--only occur here and in California. Prof. Baird notes 40 genera of birds which are represented by distinct allied species in the western, central, and eastern divisions of the United States, corresponding to our sub-regions. Plate XIX. [Illustration] THE AMERICAN PRAIRIES, WITH CHARACTERISTIC MAMMALIA.