摘要：Since 1962 a serial excavation of Usu shell-mound in Hokkaido has been made by Prof. KoHAMA and his staffs of Osaka University. Their efforts have resulted in recovery of many human skeletal and cultural remains belonging to the six cul-tural periods, namely, epi-Jomon (Kamegaoka), succesive period of Jomon (Esan), Satsumon pottery period, Muromachi-Momoyama period, early and late period of Edo era. These remains are expected to serve to solve the pending problems when and whence did ancestors of Ainus migrate to Hokkaido.The present study intended to solve some of the problems above mentioned, with the metrical and observational investigations of three skulls of the remains of Muromachi-Momoyama period, and to determine racial affinity of them. These three skulls showed many ainoid characteristics, namely, l) dolicocrany, 2) simple serration of sutures, 3) square-shaped orbits, 4) rounded lower margines of man-dible and 5) broad ramus, while there were some measurements and indices which deviate considerably from those of Ainus. In order to determine to which race they belong, the author used the discriminant function with which each skull was classified into one of three groups (Ainu, Kinki-Japanese and Tohoku-Japanese) and the result showed that all skulls were classified into Ainu.The fluorine method for determination of the relative antiquity of bone has not been considered as a strict method because there are variabilities even in bones which belong to same period. But, if data of fluorine contents from a number of samples are statistically analysed, it may be possible to determine the period of samples. Fragments from twelve individuals of each period were used for fluorine determination. It was concluded that, in spite of passable variability of fluorine contents in same individual and same period, there was increasing tendency of fluorine with burial age and fluorine contents of bones of epi-Jomon could be statistically distinguished from those of the periods after Satsumon.
