Examination of approximately 210 collections of hydroids from the Galveston Bay, Texas, area resulted in the identification of twenty-nine species representing nineteen genera in ten families. Three of these species (Stylactis n. sp., Lovenella n. sp., and Campalecium n. sp.) are provisionally described as new, but are not assigned specific epithets for reasons stated in the text. Nine species (Perigonirnus jonesi, Eudendrium exiguum, Eudendrium eximium, Clytia johnstoni, Lovenella gracilis, Lovenella grandis, Halecium bermudense, Sertularia mayeri, and Plumularia floridana) are new records for Texas waters, one species (Perigonimus repens) is new for the Gulf of Mexico, and one species (Clytia longitheca) is new for the Atlantic coast, having been previously reported only from the North American Pacific coast. The species collected are briefly discussed as belonging to one or more of three hydroid "faunas" : a sargassum fauna (restricted to or common on sargassum); an invertebrate epifauna (common on other invertebrates, e.g., mollusks or crustaceans); and a typical hydroid fauna (occurring on any suitable substrate). A brief zoogeographical discussion is presented, and it is concluded that the hydroid fauna of the area has affinities with both the southern U.S. Atlantic coast and the Caribbean, but is closer to the Atlantic coast. A key, verbal descriptions, and figures of the sixty-two species of hydroids now reported from the coasts of Texas and Louisiana are presented.