x 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 Giraffidae: 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 Ruminants. 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 structure 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 mammalan round contours 
are elliptical. 
The genus Camelus, confined to the Old World, is 
made up of two quite distinct species, the Bactrian Camel, 
C. bactrianus, with two humps, and the Dromedary, C. 
dromedarius, with only one. The 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 be 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 
1 This is the winter dress. In the summer both camels lose their long rough 
hair. 
