2002 Volume 61 Issue 1-2 Pages 41-48
We surveyed distributions of Bradybaena pellucida and B. similaris in the Boso Peninsula. B. pellucida is known to occur discontinuously in western Japan and in a limited area around Tateyama, at the southern end of the Boso Peninsula. B. similaris is cosmopolitan, distributed on most islands of Japan. The two species are closely similar to each other in shell and genital morphology, except for the color of the mantle surface, which is visible through the shell. We have found that B. pellucida predominantly occurs across the southern Boso Peninsula and is sympatric with B. similaris at several localities. B. similaris is dominant north of the range of B. pellucida.