Anableps, a genus of soft-rayed fishes of the carp family (cyprnidae), so named because the division of the cornea and iris by transverse ligaments gives the appearance of double eyes, from the dumb-bell-shaped pupil. The lens, retina, and vitreous humor are single. As one half of each eye apparently looks upward and the other half downward, they have been popularly called four-eyed fishes. The A. Gronovii or tetrophthalmus, of Surinam and Cuyuni rivers, is about 10 inches long, with a cylindrical body and strong scales, flattened head, and blunt snout with the upper jaw the longer. This genus is also viviparous, but the vascular adhesion of the embryonic membranes is ruptured long before the birth of the young, instead of at the time of exclusion as in mammals; the gestation is almost wholly ovarian. (See Fishes.)