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a family of amphibians of the order Caudata. The head is wide and flattened, and the eyes are very small and lidless. The body is large and oblate. There are four toes on each of the forelegs and five toes on each of the hind legs. The tail is laterally compressed. The amphibians appear not to have completed larval transformation; they retain two or four branchial arches, but gills are absent. The coloration is brown, sometimes with black or yellow spots.
There are two genera, embracing three species. The genus Cryptobranchus has a single species, the hellbender (C. alleganiensis), which inhabits central and southeastern North America. The hellbender is about 68.5 cm long. A wavy skin fold, rich in blood vessels that play an important role in cutaneous respiration underwater, is found along the sides of the body and along the edges of the hind legs. The hellbender inhabits swiftly flowing rivers, as well as mountain streams with relatively large rapids, and hides under rocks and in other places in daytime. It feeds on worms, crustaceans, fishes and amphibians. Reproduction occurs in late August and early September. About 450 round eggs, measuring about 6mm in diameter and joined into two beaded cords, are deposited on the river bottom. Several females spawn in one place. Fertilization is external. Males usually lie among the eggs to guard them; occasionally they consume some of the eggs. The larvae emerge from the eggs after 68 to 84 days. They lose the external gills in the 18th month of life.
The other genus, Andrias, embraces two species, the giant salamander, which is found in Japan, and A. davidianus, which is distributed in East China.
I. S. DAREVSKII