Page:Natural History (1848).djvu/188

178 the bottom of this cellular apparatus. The deep cells of the reticulum, are arranged in twelve rows, and are formed by muscular bands intersecting each other transversely. This compartment in the Camel appears to be destined exclusively as a reservoir for water, never receiving solid food, as in the Ox or Sheep." Sir E. Home Ghee "It would appear that Camels, when accustomed to journeys in which they are kept for an unusual number of days without water, acquire the power of dilating the cells, so as to make them contain a more than ordinary supply for their journey." Though this structure has been commonly considered as peculiar to the true Camels, Dr. Knox has shown that the Llamas possess a similar apparatus.

The remaining characters of the Camelidæ are the absence of horns, the great length of the neck, the comparatively small size of the head, the prolongation and mobility of the upper lip, which is deeply cleft by a vertical fissure, and the absence of a naked muzzle, the nostrils forming merely two transverse slits in the skin, which can be closed at the will of the animal.

There are but two genera, one of which is confined to the sandy deserts and arid plains of the Eastern Hemisphere, and the other to the rocky ridges of the Andes in the Western.

The true Camels are distinguished by possessing a broad callous pad or sole, by which the toes, free and separable above, are connected beneath, which is wanting in the American genus; and by the