THE CAMELS AND LLAMAS 



991 



Ruminants and the chevrotains, and which probably have had a totally distinct 

 origin from more primitive even-toed Ungulates. 



An important point of distinction is that the front of the upper jaw is furnished 

 with incisor teeth; it is true, indeed, that in the adult state there is only a single 

 pair of these teeth remaining, but in young animals there are, as in pigs, three pairs. 

 Then, again, both jaws are furnished with tusks or canine teeth; those of the lower 

 jaw being sharply pointed, and separated by an interval from the 

 incisors, instead of resembling the latter and forming with them 

 a continuous series, as we have seen to be the case in the chev- 

 rotians and the true Ruminants. The molar teeth have tall and 

 crescent-shaped crowns, which, however, are not precisely similar 

 to those of the group last named; and one, or sometimes more, of 

 the premolar teeth generally has a simple pointed crown, like that 

 of a canine, and is not in contact with the other teeth of the cheek 

 series. These isolated premolar teeth are seen in the figure of the 

 skeleton of the camel, in the gap between the tusks and the other 

 cheek-teeth. 



The limbs are long, and the thigh is placed nearly vertically, 

 so that the true knee is more detached from the small hind- 

 quarters of the body than is usually the case in Ungulate Mam- 

 mals. The lower portion of the legs is composed of a canon bone 

 supporting two toes, without any trace of the lateral toes or their 

 metacarpal bones. The canon bone differs, however, from that 

 of the true Ruminants, in that the two pulley-like surfaces at the 

 lower end, instead of being placed side by side and furnished with 

 a distinct ridge in the middle of each, are divergent, and perfectly 

 smooth. The bones of the first joint of the toes are also longer and more expanded 

 at their lower ends than in the true Ruminants; the second pair being broad and flat- 

 tened, while the third form mere nodules, quite unlike the symmetrical ones of the lat- 

 ter group. The feet form broad expanded cushion-like pads 

 (from which the group derives its title of Tylopoda), of 

 which the under surface is undivided, while the front shows 

 a division into two toes, each of which bears a broad nail 

 on the upper surface. The ankle joint differs from that of 

 the true Ruminants in that the two bones lying immediately 

 below the astragalus, remain distinct, whereas in the former 

 they unite into a compound bone, termed the naviculo- 

 cuboid. A further distinction is to be found in the divided 

 upper lip, like that of a hare; while the elongated neck is 

 characterized by the great length of its component vertebrae. 

 These vertebra exhibit certain peculiarities of structure into 

 the consideration of which we need not enter here; but it 

 must be observed that they resemble those of the true Rumi- 

 nants in that the process in front of the second vertebra, 

 by which it articulates with the first, is spout shaped. Here, then, we have 



BONES OF THE 

 LEFT FORE- FOOT 

 OF THE CAMEL. 

 (From Dawkins.) 



WATER CELLS IN STOMACH 

 OF CAMEL. 



