UDomledge & Selentifie flems 



A MOXllll.N' lOlRXAL C)l- SCIBNCK. 



Vol. I. No. 2. 



[NEW SEKir.s] 



MARCH, 1904. 



r Entered at 

 LStationers' Hall. 



si.\i'i:nci;. 



Contents and Notices. See Page VH. 



TKe Arvcestry of the 

 CoLmeL 



By R. LVDEKKER. 



Camels — or rather some of their immediate ancestors — 

 have been accorded a privilege commonly said to be 

 reserved among ourselves for the fair sex ; in other 

 words, metaphorically speaking, they have been per- 

 mitted to change their minds. l"or there can be little doubt 

 that when these animals originally started on the road 

 of getting up in the world — that is to say, on a course of 

 specialised development — they intended to become good 

 and typical ungulates like their distant cousins the true 

 ruminants ; and, for a time at least, the ancestral camels 

 appear to have had their toes encased in good service- 

 able hoofs of horn. For some reason or other, of which 

 we are at present quite ignorant, they appear to have 

 considered that this plan was a mistake, and they accord- 

 ingly struck out a line of their own, and underwent a 

 kind of retrv-gade evolution, with the result that in their 

 modern descendants their feet, instead of being covered 

 with hoofs, are fitted with large spreading and elastic 

 cushions, in which the two toes are to a great extent 

 buried, bearing small nails on their upper surface only. 

 The reason for this remarkable modification is not very 

 easy to see. It is true, indeed, that the cushion-like feet 

 of the typical camels of the Old World (from which the 

 group derives its scientific title of Tylopoda) are admirably 

 adapted for walking on the yielding sands of the deserts 

 of Central Asia and Africa. But, on the other hand, such 

 deserts are likewise the home of many hoofed ruminants, 

 such as the North African addax antelope and the 

 Mongolian gazella. Again, the wild representatives of 

 the South American llamas (which, in a collective sense, 

 also come under the denomination of camels) are asso- 

 ciated in their native wilds with the guemal deer, which, 

 like the rest of its kind, has horny hoofs of the normal 

 type. Moreover, the wild ^longolian ponies inhabit the 

 same tracts as the half-wild camels of the same country. 

 All that can be said, therefore, is that we must take 

 facts as we find them ; and that, for some reason with 

 which we are unacquainted, the members of the camel 

 tribe have developed a type of foot quite imlike that of 

 any other ungulates, and well adapted, although by no 

 means essential, to the countries where these animals are 

 found. Away from such tracts, the feet of camels are, 

 however, not infrequently a source of inconvenience, or 

 it may be absolute helplessness, to their owners. For 

 instance, on the smooth ^' kankar " roads of the Punjab, 



which in wet weather become sticky and slippery, camels 

 are utterly unable to progress, their washlealher-like 

 padded feel sliding from under thorn, and rendering 

 them as helpless as a cat on ice. 



.\lthough, m a literal sense — that is to say, from the 

 fact that they "chew the cud" — the members of the 

 camel tribe are ruminants, yet they are structurally very 

 different from the true ruminants — the Pecora of zoolo- 

 gists — and are consequently referred to a separate group 

 of equal value, for which the aforesaid name of Tylopoda 

 is now in general use. 



In addition to their cushion-like feet, camels (including 

 now and hereafter all the existing members of the group 

 and their immediate ancestors under this title) are 

 broadly distinguished from the true ruminants by the 

 following fc^itures : — 



In the first place, instead of having the front of the 

 upper jaw entirely toothless, the full series of three pairs 

 of incisor teeth are present in the young, while in the 

 adult the outermost of these pairs are an isolated curved 

 and pointed tooth, and there is also a well-developed 

 pair of canines, or tusks. Again, the lower canines, in 

 place of being approximated to the incisors and resem- 

 bling them in shape, retain the more usual isolated posi- 

 tion and sharply-pointed form. As regards the cheek- 

 teeth, although the majority of these are of the crescentic 

 type characteristic of all ruminating mammals, yet there 

 are certain peculiarities in form whereby they are readily 

 distinguished from those of the true ruminants; and, 

 what is more important still, one or more at the front of 

 the series are usually detached from those behind, and 

 assume a sharply-pointed form. 



In the skeleton the thigh-bone, or femur, is placed 

 much more vertically, by which means the thigh is 

 much more distinct from the flank, while the knee-joint 

 is placed lower down than in the true ruminants. Another 

 peculiarity is to be found in the unusual length and 

 pointed form of the knee-cap, or patella. Then, again, 

 none of the bones of the wrist and ankle-joints Ccarpus 

 and tarsus) are welded together. As regards the lower 

 part of the limbs, although the upper segments of the 

 two remaining toes (the third and fourth of the typical 

 series of ti\e) are welded together to form a cannon- 

 bone (fig. I); yet they diverge to a much greater extent 

 at their lower extremities than is the case with the true 

 ruminants. Moreover, in place of each of the two lower 

 articular surfaces of the cannon-bone having a projecting 

 ridge to fit into a groove in the upper surface of the 

 uppermost toe-bone, such surfaces are perfectly plain 

 and smooth (fig. 1). Probably, owing to the nature of 

 the foot itself, there is less liability to dislocation than in 

 the hoofed feet of the true ruminants, and a " tongued 

 joint " is therefore unnecessary. As regards the toe- 

 bones themselves, it will suffice to say that the third or 

 terminal pair form small irregular nodules, quite unlike 

 the symmetrically flattened form characterising those of 

 the true ruminants. 



