Glass  and adult Eel all species including Anguiila Japonica.Body elongate, cylindrical anteriorly, compressed posteriorly, fleshy and smooth.  Mouth corner extending to posterior margin of eyes. Lower jaw slightly longer than upper. Lips with fold, symmetrical. Snout depressed and stout.  Distance between dorsal fin origin and vent varies from 9.0 to 13.5 % of total body length. Head length 11.2 to 11.9 % in body length. Upper jaw length contained from 3.7 to 4.3 times in head length. Length of pectoral fin from 2.2 to 3.7 % of head length.  Teeth small, conical, in cardiform bands on jaws and vomer. Maxillary teeth in a narrow band. Vomerine teeth band slightly broader and longer than (or as long as) that of maxillary (Chen & Weng, 1967).  Dorsal and anal fins confluent with caudal fin. Distance between origins of dorsal and anal shorter than head length.  Body covered with rudimentary imbedded scales which arranged in small groups and placed obliquely at right angles to those of neighboring groups.  Plain-colored, not marbled or mottled. Specimens in alcohol are uniformly dark brown on the back and lighter on the belly.  114 to 117 vertebrae (average 115.8) (Lindberg & Legeza, 1969).