Opisthobranch cephalaspidean mollusks (Gastropoda: Opisthobranchia) of Vostok Bay, Sea of Japan. Part 2
The fauna of shell-bearing opisthobranch molluscs of Vostok Bay (Japan Sea) includes 10 species of the order Cephalaspidea. The list is based on the specimens collected during 2005-2016. The second part of the paper deals with three species of the families Retusidae ( Retusa instabilis Minichev, 1971, Retusa succincta (A. Adams, 1862) and Retusa minima Yamakawa, 1911) and two species of the family Aglajidae ( Melanochlamys ezoensis (Baba, 1957) and Philinopsis gigliolii (Tapparone-Canefri, 1874)). Description and images of some details of internal morphology of Retusa instabilis Minichev, 1971 is given for the ﬁrst time. Distribution and synonymy of some species are discussed.