[EN] A systematic account is provided of the siphonophores, medusae, ctenophores, molluscs and salps net-collected in basins of the Gulf of Maine and adjacent canyons during three cruises carried out in September 2002, 2003 and 2004. We describe the siphonophore Lensia quadriculata sp. nov. and the hydroidomedusae Jeanbouillonia maserati gen. nov. et sp. nov., the latter is the first member of the new family Jeanbouilloniidae. New observations are made about the morphology and/or systematics of the siphonophore Gilia reticulata and the hydroidomedusae Bougainvillia platygaster, Bougainvillia principis, Modeeria rotunda, Clytia hemisphaerica, Orchistoma collapsum and Dichotomia cannoides. Parasites associated with the ctenophores Pleurobrachia pileus (a cestode) and Beroe sp. (a hyperid amphipod) are reported.[ES] Se presenta un directorio sistemático de los sifonóforos, medusas, ctenóforos, moluscos y salpas recogidos con redes en las cuencas del golfo de Maine y cañones submarinos adyacentes durante tres cruceros realizados en septiembre de 2002, 2003 y 2004. El sifonóforo Lensia quadriculata sp. nov. y la hidroidomedusa Jeanbouillonia maserati gen. nov. et sp. nov. son descritos, ésta última especie es el primer miembro de la nueva familia Jeanbouilloniidae. Se aportan nuevas observaciones sobre la morfología y/o posición sistemática del sifonóforo Gilia reticulata y de las hidroidomedusas Bougainvillia platygaster, Bougainvillia principis, Modeeria rotunda, Clytia hemisphaerica, Orchistoma collapsum y Dichotomia cannoides. Se registran algunos parásitos asociados a los ctenóforos Beroe sp. (un anfípodo hipérido) y Pleurobrachia pileus (un céstodo).The scientific results of this study and the publication have been funded by the Belgian Fonds Léopold III pour l’Exploration et la Conservation de la Nature. We thank the captains and crew of the Seward Johnson vessels for assisting with all aspects of animal collection. The Institut Royal des Sciences Naturelles de Belgique is acknowledged for the loan of biological material deposited there. The Japanese Society for Promotion of Science supported FP in a part of this study. This research was supported by grants to MY from the National Science Foundation (OCE 0002493) and the Harbor Branch Oceanographic Institution. This study has been conducted in the frame of the Census of Marine Zooplankton project. We thank two anonymous referees by their useful comments. Harbor Branch Oceanographic Institution Contribution No. 1637.Peer reviewed