PROC. BIOL. SOC. WASH. 94(2), 1981, pp. 535-560 A REVISION OF THE NETTASTOMATID EEL GENERA NETTASTOMA AND NETTENCHELYS (PISCES: ANGUILLIFORMES), WITH DESCRIPTIONS OF SIX NEW SPECIES David G. Smith, James E. Bohlke, and P. H. J. Castle Abstract. — The genera Nettastoma Rafinesque and Nettenchelys Alcock form an easily recognized group within the family Nettastomatidae. The posterior nostril is displaced dorsally to the top of the head or behind it. The body is deepest in the middle and tapers at both ends. Nettastoma has a longer snout and 11-14 pores along the upper jaw; Nettenchelys has a shorter snout and 8-10 pores along the upper jaw. The position of the pos-terior nostril varies greatly among species of the two genera. The larva in both genera is deep-bodied anteriorly and tapers sharply toward the tail. Nettastoma contains four species. Nettastoma melanura Rafinesque (At-lantic), N. syntresis n. sp. Smith and Bohlke (Atlantic), and N. solitarium n. sp. Castle and Smith (Indo-Pacific) have the posterior nostril above the anterior edge of the eye. They are distinguished inter alia by the number of supraorbital and lateral-line pores and the relative size of the median vomerine teeth. Nettastoma parviceps Giinther has the posterior nostril over the posterior edge of the eye. Metopomycter denticulatus Gilbert is synonymized with Nettastoma parviceps, and the genus Metopomycter is synonymized with Nettastoma. Nettenchelys contains five species. Net-tenchelys pygmaeus n. sp. Smith and Bohlke (Atlantic) and TV. gephyra n. sp. Castle and Smith (Indo-Pacific) have an enlarged median series of an-terior vomerine teeth, and the posterior nostril is slightly behind the pos-terior edge of the eye; N. pygmaeus is mature at 150-200 mm TL, N. gephyra at about 400 mm. Nettenchelys inion n. sp. Smith and Bohlke, (Atlantic), N. exorius n. sp. Bohlke and Smith (Atlantic), and TV. taylori Alcock (Indo-Pacific) lack the enlarged anterior vomerine teeth and have the posterior nostril at or behind the occiput. In TV. inion the posterior nostril is just in front of the supratemporal canal, in N. exorius slightly behind the occiput, and in TV. taylori between the dorsal-fin origin and the anus. The Nettastomatidae are a rather poorly known family of eels inhabiting the outer continental shelf and the continental slope of the world's tropical and warm temperate oceans. Closely related to the Congridae, nettasto-matids are characterized primarily by an elongation and narrowing of the
BioStor
