• Aaadonta angaurana Solem, 1976: on mobile prey
• Aaadonta constricta (C. Semper, 1874): on mobile prey
• Aaadonta fuscozonata (R. H. Beddome, 1889): on mobile prey
• Aaadonta irregularis (C. Semper, 1874): on mobile prey
• Aaadonta kinlochi Solem, 1976: on mobile prey
• Aaadonta pelewana Solem, 1976: on mobile prey
• Aatolana rapax Bruce, 1993: predator
• Aatolana schioedtei (Miers, 1884): predator
• Aatolana springthorpei Keable, 1998: predator
• Abavopsis latosoleata (Salvini-Plawen, 1973): on mobile prey
• Abranchaea chinensis F.-S. Zhang, 1964: on mobile prey
• Abronica abronia (MacFarland, 1966): on sessile prey
• Abronica payaso A. Y. Kim & Gosliner, 2024: on sessile prey
• Abronica purpureoanulata (Baba, 1961): on sessile prey
• Abronica turon A. Y. Kim & Gosliner, 2024: on sessile prey
• Abyssobela atoxica Kantor & Sysoev, 1986: predator
• Abyssocomitas kurilokamchatica Sysoev & Kantor, 1986: predator
• Abyssonemertes kajiharai Chernyshev & Polyakova, 2017: predator
• Abyssothauma psilarosis (Barnard, 1963): predator
• Abyssotrophon christae Egorov, 1993: predator
• Abyssotrophon crystallinus (Kuroda, 1953): predator
• Abyssotrophon delicatus (Kuroda, 1953): predator
• Abyssotrophon edzoevi Egorov, 1994: predator
• Abyssotrophon fusiformis Houart, Vermeij & Wiedrick, 2019: predator
• Abyssotrophon hadalis (Sysoev, 1992): predator
• Abyssotrophon hubbsi (Rokop, 1972): predator
• Abyssotrophon ivanovi Egorov, 1993: predator
• Abyssotrophon lorenzoensis (Durham, 1942): predator
• Abyssotrophon minimus (Okutani, 1964): predator
• Abyssotrophon multicostatus (A. N. Golikov & Sirenko, 1992): predator
• Abyssotrophon newmani Houart, Vermeij & Wiedrick, 2019: predator
• Abyssotrophon odisseyi (A. N. Golikov & Sirenko, 1992): predator
• Abyssotrophon panamensis (Dall, 1902): predator
• Abyssotrophon ruthenicus Egorov, 1993: predator
• Abyssotrophon soyoae (Okutani, 1959): predator
• Abyssotrophon teratus Egorov, 1993: predator
• Abyssotrophon weijencheni Houart & Buge, 2022: predator
• Acamptodaphne biconica (Schepman, 1913): predator
• Acamptodaphne eridmata Morassi & Bonfitto, 2010: predator
• Acamptodaphne solomonensis Morassi & Bonfitto, 2010: predator
• Acanthais brevidentata (W. Wood, 1828): predator
• Acanthennea erinaceus (E. von Martens, 1898): on mobile prey
• Acanthina dontelei Garcia-Talavera & Sanchez-Pinto, 2002 †: predator
• Acanthina katzi Fleming, 1972 †: predator
• Acanthina monodon (Pallas, 1774): predator
• Acanthina obesa DeVries, 2003 †: predator
• Acanthina rugosa DeVries, 2003 †: predator
• Acanthina triangularis DeVries, 2003 †: predator
• Acanthina unicornis (Bruguière, 1789): predator
• Acanthinucella paucilirata (Stearns, 1871): predator
• Acanthinucella punctulata (J. E. Gray, 1835): predator
• Acanthinucella spirata (Blainville, 1832): predator
• Acanthodaphne abbreviata (Schepman, 1913): predator
• Acanthodaphne basicincta Morassi & Bonfitto, 2010: predator
• Acanthodaphne boucheti Morassi & Bonfitto, 2010: predator
• Acanthodaphne pungens Morassi & Bonfitto, 2010: predator
• Acanthodaphne pusula (Laws, 1947) †: predator
• Acanthodaphne sabellii Bonfitto & Morassi, 2006: predator
• Acanthodoris atrogriseata O'Donoghue, 1927: on sessile prey
• Acanthodoris brunnea MacFarland, 1905: on sessile prey
• Acanthodoris falklandica Eliot, 1907: on sessile prey
• Acanthodoris globosa Abraham, 1877: on sessile prey
• Acanthodoris hudsoni MacFarland, 1905: on sessile prey
• Acanthodoris lutea MacFarland, 1925: on sessile prey
• Acanthodoris metulifera Bergh, 1905: on sessile prey
• Acanthodoris mollicella Abraham, 1877: on sessile prey
• Acanthodoris nanaimoensis O'Donoghue, 1921: on sessile prey
• Acanthodoris nanega Burn, 1969: on sessile prey
• Acanthodoris pilosa (Abildgaard, 1789): on sessile prey
• Acanthodoris pina Ev. Marcus & Er. Marcus, 1967: on sessile prey
• Acanthodoris planca Fahey & Á. Valdés, 2005: on sessile prey
• Acanthodoris rhodoceras T. D. A. Cockerell, 1905: on sessile prey
• Acanthomira uchidai (Baba, 1935): on sessile prey
• Acanthoptyx acanthinula (Crosse, 1868): on mobile prey
• Acanthoptyx subacanthinula (Crosse, 1895): on mobile prey
• Acanthotrophon aquensis Lozouet, 1999 †: predator
• Acanthotrophon ascensus (E. H. Vokes, 1976) †: predator
• Acanthotrophon aturi (Deshayes, 1865) †: predator
• Acanthotrophon carduus (Broderip, 1833): predator
• Acanthotrophon latispinosus Garrigues & D. Lamy, 2019: predator
• Acanthotrophon sentus S. S. Berry, 1969: predator
• Acanthotrophon sorenseni (Hertlein & A. M. Strong, 1951): predator
• Acanthotrophon striatoides E. H. Vokes, 1980: predator
• Acanthotrophon striatus (Gabb, 1873) †: predator
• Accidenticulabrum javanus (K. Martin, 1879) †: predator
• Accidenticulabrum sangiranensis (K. Martin, 1906) †: predator
• Acheronopa attunga Hyman & J. Stanisic, 2005: on mobile prey
• Achoronemertes scoresbyi (Wheeler, 1934): predator
• Acinodrillia amazimba Kilburn, 1988: predator
• Acinodrillia paula (Thiele, 1925): predator
• Acinodrillia viscum Kilburn, 1988: predator
• Aclyvolva coarctata (G. B. Sowerby II, 1848): on sessile prey
• Aclyvolva granularis Ma, 1986: on sessile prey
• Aclyvolva lanceolata (G. B. Sowerby II, 1849): on sessile prey
• Aclyvolva rubracarinata Fehse, 2018: on sessile prey
• Acmaturris ampla J. H. McLean & Poorman, 1971: predator
• Acmaturris brisis Woodring, 1928 †: predator
• Acmaturris comparata Woodring, 1928 †: predator
• Acmaturris pelicanus E. F. García, 2008: predator
• Acodontaster conspicuus (Koehler, 1920): predator