Abstract
Two pelagic species Siriella izuensis Murano and Fukuoka, 2008 and Siriella japonica Ii, 1964, are reported for the first time from the Korean waters, together with descriptions and illustrations. S. izuensis can be distinguished from its closest relative, Siriella japonica, by the normal inner flagellum of the antennule of males, as opposed to the swollen proximal part in S. japonica, and by the slightly more distinct tendency of alternate arrangement of spines on the distal third lateral margin of the telson than in S. japonica. S. izuensis and S. japonica differ distinctly from other related species by a combination of the triangular rostral plate, the moderate size of the eyes, the form and arrangement of the lateral spines of the telson, and six or seven graded spines on the distal outer margin of the uropodal exopod. A taxonomical key is given for the genus Siriella from the Korea waters.