Dodatak:Popis žarnjaka, R
Ra
uredi- Raabeia furciligera Janiszewska & Krzton 1973
- Raabeia gorlicensis Janiszewska 1955
- Raabeia magna Janiszewska 1957
Cnidaria → Myxozoa → Myxosporea → Actinomyxida → Triactinomyxidae
- Radicipes
- Ralpharia
- Ramirezia
- Ransonia krampi (Ranson, 1932)
Cnidaria → Hydrozoa → Trachymedusae → Rhopalonematidae
- Rathkea
- Rathkeidae
Re
uredi- Renilla
- Renillidae
- Resomia
- Resomiidae
Rh
uredi- Rhabdoon
- Rhacostoma
- Rhaptapagis
- Rhipidogorgia
- Rhipidopathes
- Rhipiopathes
- Rhizalcyon
- Rhizangiidae
- Rhizocaulus
- Rhizogeton
- Rhizophysa
- Rhizophysidae
- Rhizopsammia
- Rhizorhagium
- Rhizosmilia
- Rhizostoma
- Rhizostomatidae
- Rhizostomeae
- Rhizotrochus
- Rhodactis
- Rhodalia
- Rhodaliidae
- Rhodaniridogorgia
- Rhodelinda
- Rhombopsammia
- Rhopalonema
Porodica Rhopalonematidae Russell, 1953
uredi- Aglantha Haeckel, 1879
- Aglaura Péron & Lesueur, 1810
- Amphogona Browne, 1905
- Arctapodema Dall, 1907
- Benthocodon Larson & Harbison, 1990
- Colobonema Vanhöffen, 1902
- Crossota Vanhöffen, 1902
- Pantachogon Maas, 1893
- Persa McCrady, 1859
- Ransonia Kramp, 1947
- Rhopalonema Gegenbaur, 1857
- Sminthea Gegenbaur, 1857
- Tetrorchis Bigelow, 1909
- Vampyrocrossota Thuesen, 1993
- Voragonema Naumov, 1971
Cnidaria → Hydrozoa → Trachymedusae → Rhopalonematidae
- Rhopilema
- Rhysia
- Rhysiidae
- Rhytisma
Ri
uredi- Ricordea
- Ricordiidae
- Riisea
Ro
uredi- Rolandia
- Rosacea
- Rosalinda
- Rosalindidae
- Rosgorgia
Ru
uredi- Rudjakovia
- Rumphella