PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON lll(l):230-240. 1998. Description of Eunice weintraubi and E. wui, two new species of eunicid polychaetes from northern Gulf of Mexico Hua Lu and Kristian Fauchald (HL, FK) Department of Invertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560, USA. (HL) Department of Biological Sciences, the George Washington University, Washington, DC 20052 (USA). Abstract. — Eunice weintraubi and Eunice wui are described from shallow waters of the Gulf of Mexico and variability of morphological characters is discussed. Because large numbers of specimens are available, some features of the ontogeny of Eunice wui are also noted. The morphological characters of two related species, Eunice fauchaldi and Eunice multicylindri are compared to each other and to Eunice wui. Eunicid polychaetes from the Gulf of Mexico were studied by Gathof (1984) based on benthic surveys off Florida, Lou-isiana and Texas. The specimens from these surveys and other, similar surveys were de-posited in the Smithsonian Institution. A study intended to verify the accuracy of identifications showed that many of the pre-vious identifications were inaccurate at the species level. The specimens here studied were in part those reported by Gathof (1984), but much of the material has never before been reported in a systematic study. The morphological terminology was de-fined in Fauchald (1992) except for inter-pretation of the prostomial appendages. Traditionally these have been considered as one to five occipital antennae; terms such as outer lateral, inner lateral and median an-tennae have been used (Fauchald 1992 used the abbreviations AI-AIII) for the antennae, and other terms may be found in the liter-ature (Fauvel 1923, Hartman 1944). Orrhage (1995), based on innervation, demonstrated that the outer lateral antennae (=AI) are ho-mologous with palps in other polychaetes. Consequently, the eunicids have three an-tennae: a median antenna and paired lateral antennae. Orrhage also suggested that the so-called frontal antennae (Fauchald 1982a) or frontal palps (Paxton 1986) of onuphids are paired dorsal lips. This finding has con-sequences for our understanding of the eu-nicid prostomium. The anterior end of the head in eunicids is usually notched or bifid. Positionally, this notch corresponds to the cleft between the dorsal lips of the onu-phids. If the cleft portion of the eunicid head corresponds to the onuphid dorsal lips, the position of the antennae can no longer be considered occipital. Instead the eunicid antennae become located in much the same position as in other polychaetes (e.g., he-sionids, syllids and scale-worms). The eu-nicid prostomial appendages are here re-named to include a median and paired lat-eral antennae and a pair of palps usually found lateral to and in front of the lateral antennae. All the specimens were observed under stereo and compound light microscopes; sketches for the illustrations were made us-ing camera lucida. Eunice weintraubi, new species Figs, la-h, 2 Materials examined. — Holotype: USNM 090037, off Panama City, Florida, MAFLA, 37 m, STA V-2528, 29°54'59"N, 86°04'59"W, Feb. 1978. Paratype: USNM 090037 (n = 1, STA v-2528); USNM 090039 (« = 3, STA 2528).