A new estuarine species, Nereis garwoodi (Polychaeta: Nereididae), from Bahía Chetumal, Mexican Caribbean coast.

Nereis garwoodi n. sp. is described on the basis of eight syntype specimens (six atokous and two heteronereis) collected in Bahía Chetumal, Mexican Caribbean coast, and the variability in the paragnath numbers in the pharynx is established using 180 specimens; paragnath numbers are I:10(SD = 1.9); II:30 (SD = 2.6); III:41 (SD = 5.2); IV:29 (SD = 3.5), V:1, VI:4, VII-VIII: > 30. Its eyes are big and its longest tentacular cirri reaches setiger 11. A revised key to species of Nereis recorded from the Grand Caribbean Sea is included.