THE prolific nature of the Pacific fauna is well shown by this intensive study of the starfish. The region covered by this report includes all the waters north of a line drawn from the southern end of Sakhalin to the southern boundary of the United States; and when this vast area is examined, the north-east Pacific portion of it turns out to be not only the most fertile section, but, as regards starfishes, the most prolific in species and individuals of any portion of the world. Even though the deep-water forms are little known, ninety-six species (of the twenty-three families under consideration) are described and figured, and another bulletin is promised in which the remaining large super-family Forcipulata (including the genus Asterias) is to be described. The descriptions are based upon a large, often a very large, amount of material, and include minute descriptions of the oexternal features, together with other anatomical characters. The compilation of such a work has involved a vast amount of labour extending over several years, and the result is a monograph of value to every museum. A full estimate of the work can only be made when the complementary volume is published.