O. blattae, O. blatticola, O. hydrophili, O. megatyphlon, O. spirotheca, [142]

Paddle worm, [313]

Paedogenesis, [151]

Pagenstecher, on Nemertinea, [99]

Palaemonetes, host of Nectonema, [174]

Palaeonemertea, [109], [112];

characters, [111];

development, [113]

Palaeozoic, Serpulidae, [301];

Eunicidae, [302];