WAcanthochondria
WAcanthochondria cornuta
WAcanthochondria limandae
WAnelasma
WArgulus foliaceus
WArgulus japonicus
WBarnacle
WCeratothoa oestroides
WCrustacean larva
WChondracanthidae
WClistosaccidae
WClistosaccus
WCyamus boopis
WCymothoa exigua
WEchinoecus pentagonus
WErgasilus
WFacetotecta
WGnathiidae
WHeterosaccus
WInvavita
WLepeophtheirus
WLepeophtheirus elegans
WLepeophtheirus pectoralis
WLernaea
WLernaeenicus sprattae
WLernaeocera branchialis
WLinguatula serrata
WLoxothylacus panopaei
WMonstrilla
WMonstrilloida
WPea crab
WPentastomida
WPorocephalus crotali
WSacculina
WSacculina carcini
WSalmon louse
WSea louse
WWhale louse