The Puff-adder is the most common, as well as the most deadly, of African snakes. It is generally about four feet long; the evil-looking head is broad and flat, while the body, which is as thick as a man's arm, tapers very suddenly towards the tail. The puff-adder is of a uniform brown colour, checked with bars of darker brown and white. It is slow and torpid in all its movements, and is peculiarly dangerous from its habit of lying half buried in the sandy track, not caring to move out of the way of passers-by, as other snakes generally do; still, if not molested or trodden upon, it does not attack man. If any unfortunate creature, however, should be bitten by this reptile, death occurs in a few hours. When irritated or alarmed, this snake has the power of swelling out the whole body, from which fact it derives its popular name.