Palaemon elegans – synonym of Palaemonetes varians
Palaemon fabricii – synonym of Palaemon adspersus
Palaemon nitescens – synonym of Athanas nitescens
Palinurus vulgaris – synonym of Palinurus elephas
Pandalus brevirostris – synonym of Pandalina brevirostris
Paragnathia halidaii – synonym of Paragnathia formica
Paramysis helleri – synonym of Paramysis helleri
Paramysis spiritus – synonym of Schistomysis spiritus
Parapasiphae macrodactyla – synonym of Parapasiphae cristata
Parapodopsis cornuta – synonym of Mesopodopsis slabberi
Parapodopsis goesi – synonym of Mesopodopsis slabberi
Parathemisto abyssorum – synonym of Themisto abyssorum
Parathemisto gaudichaudi – synonym of Themisto compressa
Parathemisto gracilipes – synonym of Themisto compressa
Parathemisto oblivia – synonym of Themisto abyssorum
Parerythrops abyssicola – synonym of Parerythrops obesa
Parerythrops obesa – synonym of Parerythrops obesa
Pasiphaea multidentata sicula – synonym of Pasiphaea multidentata
Pasiphaea princeps – synonym of Pasiphaea tarda
Pasiphaea sicula – synonym of Pasiphaea multidentata
Pasipohaea principalis – synonym of Pasiphaea tarda
Pectyllis arctica – synonym of Ptychogastria polaris
Pentalasmis hilli – synonym of Lepas hilli
Peracle flemingii – synonym of Limacina retroversa retroversa
Perigonimus abyssi – synonym of Neoturris pileata
Perigonimus repens – synonym of Leuckartiara octona
Perigonimus serpens – synonym of Amphinema dinema
Perigonimus yoldiaarcticae – synonym of Halitholus yoldiaarcticae
Peringia castroi – synonym of Hydrobia ulvae
Peringia cyclolabris – synonym of Hydrobia ulvae
Peringia lusitanica – synonym of Hydrobia ulvae
Peringia paulinoi – synonym of Hydrobia ulvae
Phialidium hemisphaericum – synonym of Clytia hemisphaerica
Phialidium islandicum – synonym of Clytia islandica
Philomedes interpuncta – synonym of Euphilomedes interpuncta
Phoronis architecta – synonym of Actinotrocha sabatieri
Phoronis gracilis – synonym of Actinotrocha hippocrepia
Phoronis hippocrepia – synonym of Actinotrocha hippocrepia
Phoronis muelleri – synonym of Actinotrocha branchiata
Phoronis pallida – synonym of Actinotrocha pallida
Phoronis psammophila – synonym of Actinotrocha sabatieri
Phronima atlantica – synonym of Phronima sedentaria
Physalia cymbiformis – synonym of Rosacea cymbiformis
Physophora borealis – synonym of Physophora hydrostatica
Physophora hydrostatica – synonym of Physophora hydrostatica
Physophora myzonema – synonym of Physophora hydrostatica
Physophora philippi – synonym of Physophora hydrostatica
Plagiostomum boreale – synonym of Plagiostomum vittatum
Planaria pellucida – synonym of Planocera pellucida
Plancia gracilis – synonym of Eutima gracilis
Pleopsis minutus – synonym of Podon polyphemoides
Pleopsis polyphemoides – synonym of Podon polyphemoides
Pneumodermon ciliatum – synonym of Pneumodermopsis ciliata
Pochella polynema – synonym of Trichydra pudica
Podocoryne areolata – synonym of Podocoryne borealis
Podocoryne conchicola – synonym of Podocoryne carnea
Podon mecznikovii – synonym of Podon polyphemoides
Podon polyphemoides – synonym of Podon leuckartii
Podopsis slabberi – synonym of Mesopodopsis slabberi
Polyphyes ungulata – synonym of Hippopodius hippopus
Pontophilus bispinosus – synonym of Philocheras bispinosus
Praniza coerulata – synonym of Gnathia maxillaris
Praniza coeruleata – synonym of Gnathia oxyuraea
Praniza edwardsii – synonym of Gnathia oxyuraea
Praniza fuscata – synonym of Gnathia maxillaris
Praniza obesa – synonym of Gnathia vorax
Praunus integer – synonym of Neomysis integer
Praya (Huxleya) californica – synonym of Rosacea cymbiformis
Praya cymbiformis – synonym of Rosacea cymbiformis
Praya galea – synonym of Rosacea cymbiformis
Praya maxima – synonym of Rosacea cymbiformis
Protosiriellis jaltensis – synonym of Siriella jaltensis
Pseudanchialus megalolepis – synonym of Boreomysis tridens
Pseudevadne tergstina – synonym of Evadne tergestina
Pseudocuma cercaria – synonym of Pseudocuma longicornis
Pseudomma abbreviatum – synonym of Amblyops abbreviata
Pseudomma kempi – synonym of Amblyops kempi
Pseudosiriella frontalis – synonym of Siriella armata
Pterophora conchacea – synonym of Carinaria lamarckii
Pterosagitta mediterranea – synonym of Pterosagitta draco
Pterotrachea lophyra – synonym of Carinaria lamarckii
Pterotrachea navigera – synonym of Carinaria lamarckii
Purena brownei – synonym of Dipurena ophiogaster
Pyrosoma atlanticum – synonym of Pyrosoma atlanticum
Pyrosoma benthica – synonym of Pyrosoma atlanticum
Pyrosoma elegans – synonym of Pyrosoma atlanticum
Pyrosoma giganteum – synonym of Pyrosoma atlanticum
Pyrosoma giganteum var. atlanticum – synonym of Pyrosoma atlanticum
Pyrosoma rufum – synonym of Pyrosoma atlanticum
Pyrosoma triangulum – synonym of Pyrosoma atlanticum