ANACONDA, an aquatic boa, inhabiting the swamps and rivers of the dense forests of tropical South America. It is the largest of all modern snakes, said to attain over 30 ft. in length. The Eunectes murinus (formerly called Boa murina) differs from Boa by the snout being covered with shields instead of small scales, the inner of the three nasal shields being in contact with that of the other side. The general colour is dark olive-brown, with large oval black spots arranged in two alternating rows along the back, and with smaller white-eyed spots along the sides. The belly is whitish, spotted with black. The anaconda combines an arboreal with an aquatic life, and feeds chiefly upon birds and mammals, mostly during the night. It lies submerged in the water, with only a small part of its head above the surface, waiting for any suitable prey, or it establishes itself upon the branches of a tree which overhangs the water or the track of game. Being eminently aquatic this snake is viviparous. It is the only large boa which is decidedly ill-tempered.