Panartus tetrathalamus – synonym of Didymocyrtis tetrathalamus
Parthenope (Parthenope) agona – synonym of Parthenope agona
Parthenope (Platylambrus) aylthoni – synonym of Parthenope aylthoni
Parthenope (Platylambrus) fraterculus – synonym of Parthenope fraterculus
Parthenope (Platylambrus) guerini – synonym of Parthenope guerini
Parthenope (Platylambrus) pourtalesii – synonym of Parthenope pourtalesii
Parthenope (Platylambrus) serrata – synonym of Parthenope serrata
Parundella aculeata – synonym of Parundella caudata
Parundella aculeata longa – synonym of Parundella caudata
Parundella caudata longa – synonym of Parundella caudata
Parundella crassicaudata – synonym of Parundella caudata
Parundella longa – synonym of Parundella caudata
Pelagonemertes irenae – synonym of Probalaenanemertes irenae
Pelagonemertes korotkevitschae
Peltarion (Platilambrus) spinulosum – synonym of Peltarion spinulosum
Petalotricha ampulla var. b – synonym of Petalotricha ampulla
Petalotricha ampulla var. c – synonym of Petalotricha ampulla
Petalotricha ampulla var. d – synonym of Petalotricha ampulla
Petalotricha ampulla var. major – synonym of Petalotricha ampulla
Petalotricha major – synonym of Petalotricha ampulla
Petalotricha pacifica – synonym of Petalotricha ampulla
Petalotricha serrata – synonym of Petalotricha ampulla
Phasmatopsis lucifer – synonym of Egea inermis
Phormocyrtis fatuosa – synonym of Pterocorys hertwigii
Phormospyris stabilis antarctica – synonym of Triceraspyris antarctica
Phormospyris stabilis scaphipes
Phormospyris stabilis stabilis
Phorticium pylonium – synonym of Phorticium clevei
Pinnixa rapax – synonym of Pinnixia brevipollex
Planktonemertes hardyi – synonym of Calonemertes hardyi
Planktonemertes hubrechti – synonym of Protopelagonemertes hubrechti
Pleuronema chrysalis – synonym of Pleuronema crassum
Pneumoderma atlanticum atlanticum
Pneumoderma atlanticum atlanticum eurycotylum – synonym of Pneumoderma atlanticum atlanticum
Pneumoderma atlanticum atlanticum pygmaeum – synonym of Pneumoderma atlanticum atlanticum
Pneumoderma atlanticum souleyeti
Pneumodermopsis paucidens paucidens
Podon polyphemoides – synonym of Pleopis polyphemoides
Podon schmackeri – synonym of Pleopis schmackeri
Polysolenia murrayana – synonym of Acrosphaera murrayana
Polysolenia spinosa – synonym of Acrosphaera spinosa
Porella apiculata – synonym of Poroecus apiculatus
Proamphorella quinquealata – synonym of Amphorellopsis quinquealata
Proplectella biangulata – synonym of Undella claparedei-group
Proplectella claparedei – synonym of Undella claparedei-group
Proplectella fastigata – synonym of Undella claparedei-group
Proplectella globosa – synonym of Undella claparedei-group
Proplectella grandis – synonym of Undella grandis
Proplectella ovata – synonym of Undella claparedei-group
Proplectella parva – synonym of Undella claparedei-group
Proplectella perpusilla – synonym of Undella claparedei-group
Proplectella praelonga – synonym of Undella claparedei-group
Proplectella subacuta – synonym of Undella claparedei-group
Proplectella subcaudata – synonym of Undella claparedei-group
Proplectella tenuis – synonym of Undella claparedei-group
Proplectellaangustior – synonym of Undella claparedei-group
Pseudocohnilembus persalinus – synonym of Pseudocohnilembus pusillus
Pseudodictyophimus gracilipes – synonym of Dictyophimus gracilipes
Psilomelissa phalacra – synonym of Peromelissa phalacra
Pterocorys hirundo – synonym of Dictyophimus hirundo
Pterotrachea minuta Bonnevie, 1920 – synonym of Pterotrachea hippocampus
Ptychocylis (Rhabdonella) amor – synonym of Rhabdonella amor
Ptychocylis (Rhabdonella) amor var. a cuspidata – synonym of Rhabdonella amor
Ptychocylis (Rhabdonella) amor var. b valdestriata – synonym of Rhabdonella amor
Ptychocylis (Rhabdonella) apophysata – synonym of Rhabdonella apophysata
Ptychocylis (Rhabdonella) apophysata var. b – synonym of Rhabdonella apophysata
Ptychocylis (Rhabdonella) spiralis – synonym of Rhabdonella spiralis
Ptychocylis acuminata – synonym of Epiplocylis acuminata
Ptychocylis acuminata var. b – synonym of Epiplocylis acuminata
Ptychocylis acuminata var. c – synonym of Epiplocylis acuminata
Ptychocylis acuminata var. semireticulata – synonym of Epiplocylis acuminata
Ptychocylis calyx var. a – synonym of Epiplocylis calyx
Ptychocylis calyx var. b – synonym of Epiplocylis calyx
Ptychocylis markusovszkyi – synonym of Favella ehrenbergii
Ptychocylis nervosa – synonym of Epicancella nervosa
Ptychocylis reticulata – synonym of Epiplocyloides reticulata
Ptychocylis undella var. a – synonym of Epiplocylis undella
Ptychocylis undella var. b – synonym of Epiplocylis undella
Ptychocylis undella var. c – synonym of Epiplocylis undella
Ptychocylis undella var. e – synonym of Epiplocylis undella
Ptychocylis undella var. f – synonym of Epiplocylis undella
Ptychocylis undella var. h – synonym of Epiplocylis undella
Ptychocylis undella var. i – synonym of Epiplocylis undella
Ptychocylis undella var. k – synonym of Epiplocylis undella