A review of the characteristics, taxonomic status, and distribution of the genus Streptocephalus in the Western Hemisphere is presented. Seven species are recognized including S. mackini and S. linderi, described as new. A key is included. Creaser's review (1930) of New World fairy shrimps of the genus Streptocephalus listed three species from North America and the Greater Antilles. Subsequently two additional species have been de- scribed, known ranges have been significantly extended, and several forms not assignable to any published taxon have been collected. It is the purpose of this paper, therefore, to review the diagnostic charac- ters of New World streptocephalids including two previously unde- scribed forms and to summarize current knowledge of their distribu- tion. DIAGNOSTIC CHARACTERS. Species of the genus Streptocephalus are differentiated primarily on the basis of the structure of the II antennae,