1. Subgenus Alcyonidium (Paralcyonidium) Okada, 1925
   1. Species Alcyonidium (Paralcyonidium) vermiculare Okada, 1925
2. Species Alcyonidium adustum Winston & Hayward, 2012
3. Species Alcyonidium albescens Winston & Key, 1999
4. Species Alcyonidium albidum Alder, 1857
5. Species Alcyonidium androsovae d'Hondt, 1983
6. Species Alcyonidium anglei d'Hondt & Goyffon, 1991
7. Species Alcyonidium antarcticum Waters, 1904
8. Species Alcyonidium argyllaceum Castric-Fey, 1971
9. Species Alcyonidium australe d'Hondt & Moyano, 1979
10. Species Alcyonidium bullitum Seo, Chae, Winston, Zágoršek & Gordon, 2018
11. Species Alcyonidium busanensis Seo, Chae, Winston, Zágoršek & Gordon, 2018
12. Species Alcyonidium candidum Ryland, 1963
13. Species Alcyonidium capronae Winston & Hakansson, 1986
14. Species Alcyonidium cellarioides Calvet, 1900
15. Species Alcyonidium chondroides O'Donoghue & de Watteville, 1937
16. Species Alcyonidium clavum Hirose, 2022
17. Species Alcyonidium columbianum O'Donoghue & O'Donoghue, 1926
18. Species Alcyonidium columnaris d'Hondt, 2014
19. Species Alcyonidium condylocinereum Porter, 2004
20. Species Alcyonidium diaphanum (Hudson, 1778)
21. Species Alcyonidium disciforme Smitt, 1872
22. Species Alcyonidium duplex Prouho, 1892
23. Species Alcyonidium effusum Norman, 1909
24. Species Alcyonidium eightsi Winston & Hayward, 1994
25. Species Alcyonidium enteromorpha Soule, 1951
26. Species Alcyonidium epispiculum Porter & Hayward, 2004
27. Species Alcyonidium erectum Silén, 1942
28. Species Alcyonidium excavatum Hincks, 1880
29. Species Alcyonidium exiguum Vieira, Migotto & Winston, 2014
30. Species Alcyonidium flabelliforme Kirkpatrick, 1902
31. Species Alcyonidium flustroides Busk, 1886
32. Species Alcyonidium foliaceum Silén, 1942
33. Species Alcyonidium gelatinosum (Linnaeus, 1761)
34. Species Alcyonidium hauffi Marcus, 1939
35. Species Alcyonidium hirsutum (Fleming, 1828)
36. Species Alcyonidium hydrocoalitum Porter, 2004
37. Species Alcyonidium irregulare Kluge, 1962
38. Species Alcyonidium jauhar Tilbrook & Gordon, 2015
39. Species Alcyonidium kermadecense Gordon, 1984
40. Species Alcyonidium kuklinskii Schwaha, Cometti, Saadi, Cecchetto & Schiaparelli, 2023
41. Species Alcyonidium lutosum Winston & Hayward, 2012
42. Species Alcyonidium maculosum Winston & Hayward, 2012
43. Species Alcyonidium mamillatum Alder, 1857
44. Species Alcyonidium multigemmatum Gordon, 1986
45. Species Alcyonidium nanum Silén, 1942
46. Species Alcyonidium nipponicum d'Hondt & Mawatari, 1986
47. Species Alcyonidium nodosum O'Donoghue & de Watteville, 1944
48. Species Alcyonidium nostoch (A.P.de Candolle) Lamouroux, 1813
49. Species Alcyonidium pachydermatum Denisenko, 1996
50. Species Alcyonidium papillatum O'Donoghue, 1924
51. Species Alcyonidium parasiticum (Fleming, 1828)
52. Species Alcyonidium pedunculatum Robertson, 1902
53. Species Alcyonidium pelagosphaerum Porter & Hayward, 2004
54. Species Alcyonidium polyoum (Hassall, 1841)
55. Species Alcyonidium polypylum Marcus, 1941
56. Species Alcyonidium proboscideum Kluge, 1962
57. Species Alcyonidium protoseideum
58. Species Alcyonidium pseudodisciforme Denisenko, 2009
59. Species Alcyonidium pulposum Seo, Chae, Winston, Zágoršek & Gordon, 2018
60. Species Alcyonidium pulvinatum Vieira, Migotto & Winston, 2014
61. Species Alcyonidium radicellatum Kluge, 1946
62. Species Alcyonidium rhomboidale O'Donoghue, 1924
63. Species Alcyonidium rugosum Silén, 1942
64. Species Alcyonidium rylandi d'Hondt & Goyffon, 2005
65. Species Alcyonidium sagamianum Mawatari, 1953
66. Species Alcyonidium sanguineum Cook, 1985
67. Species Alcyonidium scolecoideum Porter & Hayward, 2004
68. Species Alcyonidium shizuoi d'Hondt & Mawatari, 1986
69. Species Alcyonidium sileni d'Hondt, 2014
70. Species Alcyonidium simulatum Porter & Hayward, 2004
71. Species Alcyonidium torpedo d'Hondt, 2006
72. Species Alcyonidium torquatum Vieira, Migotto & Winston, 2014
73. Species Alcyonidium vahine d'Hondt & Mascarell, 2010
74. Species Alcyonidium variegatum Prouho, 1892
75. Species Alcyonidium verrilli Osburn, 1912
76. Species Alcyonidium vicarians d'Hondt & Chimenz Gusso, 2006
77. Species Alcyonidium vigelandi d'Hondt, 2014
78. Species Alcyonidium vitreum Vieira, Migotto & Winston, 2014
79. Species Alcyonidium corniculatum Smitt, 1872 accepted as Flustrellidra corniculata (Smitt, 1872) (Basionym)
80. Species Alcyonidium defractum (Velley) C.Agardh, 1927 accepted as Helminthonema defractum (Velley) Kützing, 1841 (synonym)
81. Species Alcyonidium digitatum (Linnaeus, 1758) accepted as Alcyonium digitatum Linnaeus, 1758 (Lapsus )
82. Species Alcyonidium kurilenses Mawatari, 1953 accepted as Flustrellidra kurilensis (Mawatari, 1953) (Basionym)
83. Species Alcyonidium mytili Dalyell, 1848 accepted as Alcyonidioides mytili (Dalyell, 1848)
84. Species Alcyonidium nemalion (Bertoloni) Bory accepted as Nemalion elminthoides (Velley) Batters, 1902
85. Species Alcyonidium pellucidum Leidy, 1855 accepted as Aplidium pellucidum (Leidy, 1855) (original combination)
86. Species Alcyonidium proliferans Lacourt, 1949 accepted as Alcyonidium diaphanum (Hudson, 1778) (synonym)
87. Species Alcyonidium reticulum Ryland & Porter, 2000 accepted as Alcyonidium gelatinosum (Linnaeus, 1761)
88. Species Alcyonidium topsenti Roehrich, 1910 accepted as Alcyonidium diaphanum (Hudson, 1778) (synonym)
89. Species Alcyonidium vermiculare Okada, 1925 represented as Alcyonidium (Paralcyonidium) vermiculare Okada, 1925
90. Species Alcyonidium filiforme Suhr, 1840 (uncertain)
91. Species Alcyonidium incrustans Lamouroux, 1824 (uncertain > taxon inquirendum)
92. Species Alcyonidium intricatum Suhr, 1840 (uncertain)
93. Species Alcyonidium ramosum Lamouroux, 1824 (uncertain > taxon inquirendum)

 The webpage text is licensed under a Creative Commons Attribution 4.0 License