Melibe engeli 
Melibe papillosa 
Melibe viridis 
Melo broderipii 
Mexichromis mariei 
Mexichromis pusilla 
Mexichromis trilineata 
Miamira alleni 
Miamira miamirana 
Miamira moloch 
Miamira sinuata 
Microparmarion malayanus 
Mile Cone 
Milk snail 
Miller's Nembrotha 
Millipede spider conch 
Mimic octopus 
Miniature melo 
Modiolus modiolus 
Monacha cantiana 
Monacha obstructa 
Money cowry 
Moon-headed Sidegill Slug 
Mosaic Octopus