Paleontological Study on Dermal Armor, Dermal Tooth and Tooth of Primitive Fishes.

1. 厚皮螈的皮甲：这种皮甲是在日本中部岐阜县Kmitakara-mura的虎地群（下泥盆世）中发现的。从形态学和组织学的研究来看，真皮甲被认为是棘胸龙的脊柱板。古生代软骨鱼的牙齿：Petalodus allegheniensis的牙齿？Chomatodus sp.和？对日本中部中石炭世的Janassa sp.、下二叠世的p.a.和中二叠世的Sandlodus sp.进行了研究。3 .中生代Elasmobranchii的牙齿：对日本中三叠统Hybodus sp.、上三叠统Acrodus sp.和下侏罗统Asteracanthus sp.的牙齿进行了研究。第三纪蓝齿鲨牙齿的修复：巨齿鲨的颌骨和牙齿修复于富山科学博物馆。描述了两颗来自福建中新世的Isurus属的牙齿。软骨鱼牙齿的进化：对化石和现存软骨鱼牙齿的形态和组织学进行了研究。可以认为，软骨鱼的牙齿结构并不取决于它们的进化水平，而是适应它们的饮食习惯的结果。

1. Dermal armor of Placodermi : The dermal armors were discovered from the Hukuji Group (Lower Devonian) in Hukuji, Kmitakara-mura, Gifu Prefecture, central Japan. From the morphological and histological studies, the dermal armor is presumed as spinal plates of Romudina sp., Acanthothoraci.2. Tooth of Paleozoic Chondrichthyes : Teeth of Petalodus allegheniensis, ?Chomatodus sp. and ?Janassa sp. from the Middle Carboniferous, P. a. from the Lower Permian and Sandlodus sp. from the Middle Permian of central Japan were investigated.3. Tooth of Mesozoic Elasmobranchii : Teeth of Hybodus sp. from the Middle Triassic, Acrodus sp. from the Upper Triassic and Asteracanthus sp. from the Lower Jurassic of Japan were investigated.4. Restoration of dentition of Tertiary Elasmoblanchii : The jaws and dentition of Carcharocles megalodon were restored in the Toyama Science Museum. Two teeth of the genus Isurus from the Miocene of Fikui Prefecture were described.5. Evolution of tooth in Chondrichthyes : The morphology and histology of teeth in fossil and extant Chondrichthyes were investigated. It can be considered that the tooth structure of Chondrichthyes is not dependent on their evolutionary levels, but the result of an adaptation to their food habits.