The CROSSROADS plankton collection extends the range of about 30 siphonophores to the Marshall Islands, but only one third of these was taken in the lagoons. Of the species recorded, Galetta bigelowi is new, Lensia grimaldii was taken in the Pacific for the first time, and Diphyes chamissonis, which is restricted to the Indo-Pacific region, was taken in quantity in Rongelap Lagoon, as it had been in the Great Barrier Reef Lagoon. The significance of this habitat in limiting the distribution of D. chamissonis is not apparent.