A new species of a cephalobaenid pentastomid infecting the lungs of a toad, Bufo lemur, from Puerto Rico is described. The single infection comprises all stages from infective larvae to mature males and females and therefore we consider the toad to be a definitive host. We reassess the evidence concerning Raillietiella indica Gedoelst, 1921, another raillietiellid from the lungs of an Indian toad, B. melanostictus which, hitherto, has been considered by most authors an immature stage from an intermediate host. It now appears that the type specimen was probably a gravid female and that R. indica is a valid species which also matures in a toad. Thus amphibians are established as a new class of definitive hosts for pentastomids. ac]19820218