- Abralia redfieldi
- Abraliopsis gilchristi
- Abraliopsis pfefferi
- Abyla bicarinata
- Abyla haeckeli
- Abyla trigona
- Abylopsis eschscholtzi
- Abylopsis tetragona
- Acanthocarpus alexandri
- Acanthochiasma fusiforme
- Acanthochiasma hertwigi
- Acanthochiasma planum
- Acanthochiasma quadrangulum
- Acanthochiasma rubescens
- Acanthochiasma serrulatum
- Acanthocolla cruciata
- Acanthocolla solidissima
- Acanthocyclus albatrossis
- Acanthocyclus gayi
- Acanthocyrtha haeckeli
- Acanthodesmia viniculata
- Acantholithium dicopum
- Acantholithium stellatum
- Acanthometra bulbosa
- Acanthometra cylindrica
- Acanthometra dolichoscia
- Acanthometra fusca
- Acanthometra pellucida
- Acanthometra prismatica
- Acanthometra tetracopa
- Acanthonyx dissimulatus
- Acanthonyx scutiformis
- Acanthoplegma krohni
- Acanthoscina acanthodes
- Acanthosphaera actinota
- Acanthosphaera dodecastyla
- Acanthosphaera pinchuda
- Acanthospira amphicopa
- Acanthospira spiralis
- Acanthospira torta
- Acanthostaurus bipennis
- Acanthostaurus conacanthus
- Acanthostaurus henseni
- Acanthostaurus purpurascens
- Acanthostomella norvegica lata
- Acanthostomella norvegica typica
- Acartia bifilosa
- Acartia centrura
- Acartia danae
- Acartia lilljeborgii