_C. (Menopoma) alleghaniensis._–The gill-clefts are normally reduced to one pair, individually to the left cleft, the right closing up. There are, however, four branchial arches and vessels. The general colour is brown or grey above, sometimes with darker patches, lighter below. The "Hellbender" reaches a length of nearly 18 inches (about 46 cm.), is entirely aquatic, and is apparently restricted to the rivers and streams of the mountainous districts of the Eastern United States. It is very voracious, living on worms and on fish, being much disliked by the fishermen, as it takes the angler's bait, and destroys great quantities of the valuable food-fish _Coregonus albus_. Although rather common and easily kept, its larvae still remain unknown. {98}[Illustration: FIG. 17.–_Cryptobranchus japonicus._ Japanese Giant Salamander. × ⅙.] {99}_C. japonicus_ s. _maximus_.–The Giant Salamander of Japan differs from its American relation in one essential point only, namely, by the absence of gill-openings and of the modifications of the branchial apparatus connected therewith. It has but three branchial vessels, and the skeletal arches are reduced to two. It lives in Japan and in China, from 600 to 4500 feet above the level of the sea, in small streams of mountain-meadows. It feeds upon fishes, Amphibia, worms, and insects. It is easily fished with the hook and is eaten by the Japanese. The first living specimen was brought to Europe in 1829 by Th. von Siebold, its discoverer. It grew within a few years from 1 foot to 3 feet in length, and died in 1881, at least fifty-two years old. Another specimen lived in the Hamburg aquarium for fourteen years, during which time it is said to have grown 36 cm. (more than 14 inches), having attained a length of nearly 4½ feet, or 134 cm. The largest specimen known measures 159 cm = 5 feet 3 inches. The life-history of this species is still imperfectly known. Japanese picture-books contain drawings of the adult and of larvae, the latter showing three pairs of fringed external gills. Young specimens of 16 cm. length have already lost the gills, but still retain a cleft on either side of the neck, in the shape of a horizontal slit, and this is soon after closed up by the skin. The best account has recently been given by Sasaki.[46] According to him the Giant Salamander leads a solitary life, concealed in dark places, under rocks in swift-flowing, thickly shaded small brooks of clear and cold water.