Palaeontological study on the fish remains from the Palaeozoic and Mesozoic of Japan.

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1) The Palaeozoic fish remains from Japan are classified into 29 species, that is, one species of Devonian placoderms, 12 species of Carboniferous to Permian elasmobranchs, seven species of Carboniferous to Permian petalodonts, eight species of Carboniferous to Permian cochliodonts and one species of Permian osteichthyans (Goto, 1996 ; 1997).(2) The Mesozoic elasmobranch remains from Japan are classfied into 58 species, that is, three species of Triassic hybodonts, five species of Jurassic hybodonts, and 50 species of Cretaceous hybodontoids, ptychodontoids, chlamydoselachoids, hexanchoids, heterodontoids, lamnoids, squaloids, pristiophoroids and sclerorhynchoids (Goto el al., 1996 ; Goto, 1996).3) Two teeth of Chlamydoselachus sp.are reported from the Izumi Group (Upper Cretaceous) of Sobura, Kaizuka City, Osaka Prefecture and the Himenoura Group (Upper Cretaceous) of Ryugatake, Amakusa-gun, Kumamoto Prefecture (Goto et al., 1996 ; 1997).4) The teeth of Carcharocles from the Godo Formation (Middle Miocene) of Kuzubukuro, Higashi-matsuyama City, Saitama Prefecture are described (Yabe and Goto, 1996).5) The morphology and structure of teeth, dermal denticles and mucous denticles of Megahasma pelagious No.7 * are observed (Goto, 1996, 1997 ; Yano et al., 1997).6) Origin and evolution of tooth and bone of vertebrates are summarized following the evolutionary grade of agnathians, sharks, bony fishes, amphibians, reptiles, mammals and humankind.