The teeth and skeleton of the llamas (_Lama_) are closely similar to those of the camels, but the absence of humps, the long, pointed ears, the woolly hair and the much smaller size and lighter build give to the living animals a more marked difference of appearance from the camels than one would expect from a comparison of the skeletons alone. The dental formula is: _i_ 1/3, _c_ 1/1, _p_ 2/2, _m_ 3/3. The remaining upper incisor, the third, is recurved, as is also the canine, but the spike-shaped first premolar of the camels is absent and the other premolars are much smaller than in the latter. In the skull the brain-case is larger, and the sagittal and occipital crests are much less prominent. The skeleton differs hardly at all from that of the camels, except for its smaller size and more slender proportions. The toes are more distinctly separated, each having its own pad. Thus, among the existing representatives of the family are two very well-defined phyla, each characteristic of a different continent. [Illustration: FIG. 208.—Guanaco (_Lama huanacus_).—By permission of the New York Zoölogical Society.] The Blanco stage of the middle Pliocene, which has preserved but a meagre representation of the life of its time, has yielded a number of very large, llama-like species, not, however, ancestral to the modern species, for they had but one premolar in each jaw. From the lower Pliocene we have fuller information. In the Snake Creek stage the separation of the two modern phyla was complete, and there was a third one, now extinct, that of the browsing or “†giraffe-camels” (_†Alticamelus_) (see Fig. 127, p. 236), a term which must not be taken as implying any relationship with the giraffes, but merely a resemblance to them in proportions. These browsing camels were very large animals, but with relatively small heads and low-crowned teeth not suited for grazing; the neck was extremely long, made so by the great elongation of five of the vertebræ (second to sixth, inclusive), and the legs were also very long, fitting their possessors to browse upon trees. Much of the description of the appearance and habits of the Giraffe given by Flower and Lydekker would no doubt be applicable to these extinct camels. “To produce the extremely elongated neck the seven cervical vertebræ are proportionately long, which gives a somewhat stiff and awkward motion to the neck.... The Giraffe feeds almost exclusively on the foliage of trees ... for browsing on which its prehensile tongue and large free lips are specially adapted.”[8]