Thirteen species of Syllinae in the genera Plakosyllis Hartmann-Schröder, 1956, Trypanosyllis Claparède, 1864, Opisthosyllis Langerhans, 1879, Dentatisyllis Perkins, 1981, Haplosyllis Langerhans, 1879, Branchiosyllis Ehlers, 1887,
and ParasphaerosylliS Monro, 1937, principally from Cuba but also from the Gulf of Mexico, are reported in this paper. A new species from the Gulf of Mexico is described, Opisthosyllis longidentata, characterized by having a very long pharyngeal tooth and irregularly wrinkled
posterior cirri. The species T. prampramensis Augener, 1918 is new to the Caribbean and Gulf of Mexico region. Plakosyllis quadrioculata Perkins, 1981, Trypanosyllis vittigera Ehlers, 1887, Dentatisyllis carolinae Perkins, 1981, Branchiosyllis exilis (Gravier,
1900) and Parasphaerosyllis indica Monro, 1937, are new to the Cuban fauna. One species of Branchiosyllis and of Trypanosyllis are identified to generic level.
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