British species, [49]
Proporidae, [49]
Proporus venenosus, [49]
Prorhynchidae, [49]
Prorhynchus sphyrocephalus, terrestrial habit, [44];
P. stagnalis, [49]
Prosorhochmus claparedii, [110], [114], [117]
Prostate-gland, of Leptoplana, [16];
of Polyclads, [30];
of Planaria, [39];