144 MAMMALIA. RUMINANTIA. 



rate, the ass, but for the horse, would have been the most valuable of our domestica- 

 ted beasts of burden. In eastern countries, however, the ass is still used for the saddle 

 and as a beast of burden ; and the qualities of its progeny, the mule, have secured 

 attention to its production in many parts of the world. In a wild state the ass is 

 still found in Kalmuc Tartary, in innumerable troops, which migrate from the north 

 to the south, and back again according to the season. The ass varies much in size, 

 and it has been observed to degenerate in this respect, according as it is removed 

 from its original country. The ass couples with the horse and the zebra, but their 

 progeny do not propagate. 



ORDER IX. RUMINANTIA. 



No incisors in the upper jaw ; in the lower usually eight ; a 

 vacant space between the incisors and molars, but in which 

 in some genera are found one or two canines ; molars twelve 

 in each jaw, the crown marked with two double crescents of 

 enamel, of which the convexity is outwards in the lower jaw, 

 and inwards in the upper ; no clavicles ; extremities dispo- 

 sed for walking ; two toes furnished with hoofs ; metacarpal 

 and metatarsal bones united ; four stomachs ; intestines long; 

 two or four inguinal mammae ; horns in the males and often 

 in the females of most species. 



This is one of the most natural groups of animals. The term Ruminantia indi- 

 cates the singular faculty possessed by them of masticating their food twice ; and 

 their stomach for this purpose consists of four parts, of which the first three are 

 disposed in such a manner that these animals can at will transmit their food from 

 the one to the other. Their food is invariably vegetables, and they are widely dis- 

 tributed over both continents. 



* Without horns. CAMELID^, Smith. 

 Gen. 136. CAMELUS, Lin. Cuv. &c. 



Incisors f , canines ^-j, false molars \-\, molars f-f = 36. 

 Inferior incisors in the form of cutting wedges ; the superior 

 lateral ; canines conical, erect, and strong ; false molars on 

 each side in the interdentary space ; toes united below ; head 

 long ; neck very long ; upper lip cleft ; nostrils slit obliquely ; 

 eyes projecting ; ears small ; back with fleshy hunches ; 

 callosities on the breast and flexures of the extremities ; four 

 ventral mammas ; hair woolly ; tail of medium length. 



C. Bactrianus, Lin. The Bactrian Camel. Two hunches on the 

 back ; colour generally brown. About 10 feet long. Inhabits 

 Persia, Turkey, &c. Shaw, ii. pi. 167- 



C. Dromedarius, Lin. The Arabian Camel. One hunch on the 

 middle of the back ; fur pale brown. Nearly eight feet long. In- 

 habits Arabia, Turkey, &c Shaw, ii. pi. 166. 



This valuable animal has been in domestication from the earliest times, and has 

 for ages been the medium of commercial communication between the countries on 

 either side of the great deserts of Arabia. For passing these extensive wastes the 



