- Chthamalophilus delagei
- Chthamalus stellatus
- Clistosaccus paguri
- Conchoderma auritum
- Conchoderma virgatum
- Coronula diadema
- Coronula reginae
- Coronulinae
- Corophium acherusicum
- Corophium affine
- Corophium arenarium
- Corophium bonnellii
- Corophium crassicorne
- Corophium curvispinum
- Corophium insidiosum
- Corophium lacustre
- Corophium multisetosum
- Corophium sextonae
- Corophium volutator
- Corystes cassivelaunus
- Crangon allmani
- Crangon crangon
- Cressa dubia
- Cressa minuta
- Cumella pygmaea
- Cumopsis goodsiri
- Cyamus catodontis
- Cyathura carinata
- Cypridacea
- Cyprideis torosa
- Cytheracea
- Cythere lutea
- Cytheropterinae
- Cytheropteron latissimum
- Dendrotion spinosum
- Desmosoma tenuimanu
- Dexamine thea
- Diastylis bradyi
- Diastylis cornuta
- Diastylis laevis
- Diastylis lucifera
- Diastylis rathkei
- Diastylis rugosa
- Diastylis tumida
- Diastyloides biplicata
- Dichelopandalus bonnieri
- Dikerogammarus villosus
- Diogenes pugilator
- Dorhynchus thomsoni
- Drepanorchis neglecta