Coluber, the principal genus of a family of ophidian reptiles, characterized by an elongated head, distinct from the neck, and covered above with smooth polygonal plates; the snout rather rounded; the eyes large, and the pupil round; the body long, cylindrical, and tapering, covered above with rhomboidal scales, generally smooth, but sometimes carinated. The tail has always double plates on the under surface; the .plates of the abdomen are transverse; the jaws furnished with numerous sharp teeth, directed backward, without poisonous fangs. Some species are oviparous, others ovoviviparous. In the old Linnsean genus coluber were included all ophidians having double plates on the under surface of the tail; this embraced many venomous serpents; the genus has since been restricted by Boie, Schlegel, and others, so that it now forms a very natural one, recognized rather by its general than by any isolated characters. Its numerous species are found in most parts of the globe where any ophidians can exist; they are generally terrestrial, rarely entering the water unless from necessity; most of them climb trees easily, where they lie in wait for .their prey; some are found in marshy districts, some in thick woods, some in open sandy plains, and the locality impresses various habits of life upon them; they generally pursue small mammals, birds, and reptiles.
They attain a considerable size, sometimes a length of 8 ft. The abdominal plates and the ribs are exceedingly numerous, sometimes as many as 300. The sides of the snout are rarely concave, and the plates over the eye are not very prominent, giving to their physiognomy a gentle expression, which is confirmed by the disposition of many of the species living in the vicinity of man. The colors are rarely brilliant, brown shading into black or green being the prevailing tints; some are striped or spotted, but all undergo considerable changes in their progress to maturity. The genus has since been subdivided into many. Among the best known species is the one dedicated to AEsculapius (C. AEsculapii, Lacep.), emblem of the sagacity and health-bestowing qualities of the great physician; and, in this country, the black snake (bascanion constrictor, B. and G.), the corn snake (scotophis guttatus, B. and G.), the chicken snake (ophibolus eximius, B. and G.), the indigo snake (Georgia Couperi, B. and G.), the green snake (chlorosoma ver-nalis, B. and G.), and the striped snake (entm-nia sirtalis, B. and G.).