XI CAMELS AND LAMAS 285 



tarsals are free, but with a tendency to fusion ; the lateral toes 

 are only represented at the upper extremity. The carpal bones 

 are separated. 



This animal, which was about the size of a Sheep, though 

 of more delicate proportions, was allied not only to the Tragu- 

 lidae but to the Giraftidae : it is impossible to refer it definitely 

 to either family. 



B. TYLOPODA. 



Fam. 5. Camelidae. — This small group of Selenodonts in- 

 cludes only the Camels and Lamas. The limbs are long and 

 have no traces of the second and fifth toes. The fused meta- 

 carpals and metatarsals diverge somewhat at their distal ends. In 

 the upper jaw is a single pair of incisors. The stomach differs 

 from that of the typical Euminants. The rumen has smooth and 

 not papillose walls, and from it are developed the " water cells," 

 diverticula with narrow mouths provided with a closing sphincter 

 muscle. The psalterium is reduced to a mere vestige, and so the 

 stomach has, as in the Tragulina, but three chambers. This, so 

 far ancient, character in the structiu:e of the Camel tribe is 

 associated with another, also seen in the more primitive Ungulates, 

 viz. the diffuse character of the placenta. A very singular 

 peculiarity of this* group is the fact that the blood corpuscles 

 instead of showing the ordinary mammalian round contours 

 are elliptical. 



The genus Cavielus, confined to the Old World, is 

 made up of two quite distinct species, the Bactrian Camel, 

 C. hactrianus, with two humps, and the Dromedary, C. 

 dromedarius, with only one. Tlie former species is Asiatic. It 

 is a singular fact that neither of the species is known to occur in 

 a genuinely wild condition. The so-called " wild " Camels appear 

 to l3e invariably feral. The two species will interbreed ; and there 

 is at the Zoological Society's Gardens such a hybrid, which has the 

 general appearance and shaggy brown hair^ of the Bactrian animal, 

 but the one hump of the Dromedary. It may be that the Bactrian 

 Camels of Lob-nor are really wild ; but the desert contains so many 

 remains of cities destroyed by sand-storms that these reputed wild 



^ This is the winter diess. In the summer both camels lose their long rough 

 hair. 



