Tars Tarkas, on his first appearance in the book, is described thus:
...long necks and six legs, or, as I afterward learned, two legs and two arms, with an intermediary pair of limbs which could be used at will either as arms or legs. Their eyes were set at the extreme sides of their heads a trifle above the center and protruded in such a manner that they could be directed either forward or back and also independently of each other, thus permitting this queer animal to look in any direction, or in two directions at once, without the necessity of turning the head.
The ears, which were slightly above the eyes and closer together, were small, cup-shaped antennae, protruding not more than an inch on these young specimens. Their noses were but longitudinal slits in the center of their faces, midway between their mouths and ears.
There was no hair on their bodies, which were of a very light yellowish-green color. In the adults, as I was to learn quite soon, this color deepens to an olive green and is darker in the male than in the female. Further, the heads of the adults are not so out of proportion to their bodies as in the case of the young.The iris of the eyes is blood red, as in Albinos, while the pupil is dark. The eyeball itself is very white, as are the teeth. These latter add a most ferocious appearance to an otherwise fearsome and terrible countenance, as the lower tusks curve upward to sharp points which end about where the eyes of earthly human beings are located. The whiteness of the teeth is not that of ivory, but of the snowiest and most gleaming of china. Against the dark background of their olive skins their tusks stand out in a most striking manner, making these weapons present a singularly formidable appearance.
...huge and terrific incarnation of hate, of vengeance and of death. The man himself, for such I may call him, was fully fifteen feet in height and, on Earth, would have weighed some four hundred pounds. He sat his mount as we sit a horse, grasping the animal's barrel with his lower limbs, while the hands of his two right arms held his immense spear low at the side of his mount; his two left arms were outstretched laterally to help preserve his balance, the thing he rode having neither bridle or reins of any description for guidance.