Abstract
The land snail fauna of the Uji-gunto, consisting of two islands, Muko-jima and Ie-jima, located at 129°29′E, 30°12′N, was surveyed in 1981 and 1983. In total, 27 species belonging to 24 genera of 13 families were collected. One subgenus, one species and one subspecies are described as new to science. The land snails of the Uji-gunto contains seven species which are regarded as Osumi elements. But, Nomura-Simpson's Coefficient (NSC) between the Uji-gunto and Yaku-shima, the Osumi Islands, is relatively small (Ie-jima-Yaku-shima : 0.455 ; Muko-jima-Yaku-shima : 0.478), compared with NSC (0.560) between Yaku-shima and Kyushu (Kagoshima-ken). Percentage of endemism in this Island group is very high, namely, one genus and six species, i.e., 22.2% are endemic at species level. For this reason, Uji-gunto is considered to be very peculiar in the land snail fauna and to have been isolated from adjacent land masses for a long period.
