Species of the family Trichotropidae are mostly distributed in cold and subtropic waters of both hemispheres. Presently, 26 species from 7 genera are known for seas of Russia and adjacent regions. Three species are described as new. A new subgenus, Ovotropis subgen. nov., is isolated in the genus Iphinoe. The taxonomic position of the genus Trichamanthina is specified: it has been previusly assigned to the family Capulidae (Golikov, 1986: 12). The character of periostracum, the presence of operculum, and the structure of radula indicate, in our opinion, that this monotypic genus belongs to the family Trichotropidae. The highest species diversity was recorded in the Okhotsk Sea: from Kamchatka to northern shores of Japan. Most species usually occur at 70 to 250 m; representatives of the family from cold and temperate waters of the northern hemisphere are distributed from the upper intertidal zone (Turritropis insignis) to depths of 944 m (Ariadnaria borealis, after Golikov, 1986: 22).
As a result of studying rich collections stored in the Zoological Institute of the Russian Academy of Sciences (St. Petersburg), the Zoological Museum of Moscow State University and the Institute of Oceanology of the Russian Academy of Sciences (Moscow), as well as private collections (a total of about 1 800 specimens), and based on an analysis of the literature, we supplemented data on ecology and distribution of trichotropids, and specified diagnoses of genera and some rare species. An analysis of original descriptions and examination of type material allowed us to revise the taxonomic position of some species and their synonymy.