Magasella Dall. 
Magdala Leach. 
Malletia Desm. 
Malleus Lam 
Mantellum Bolt. 
Margarita Leach. 
Margaritana Schum. 
Mariella Gray 
Marinula King 
Marmorostoma Sw. 
Martensia Semper 
Martesia Leach 
Mastus Beck 
Matharena Bergh. 
Medora Vest. 
Medyla Alb. 
Megaspira Lea 
Megatlıyris d’Orb. 
Megshimatium Hasselt 
Megerlia King. 
Meiocardia Ad 
Melampus Montf. 
Melaniella Pfr. 
Meleagrina Lam. 
Melibe Rang. 
Melina Retz. 
Menetus Ad. 
Mercenaria Schum. 
Meretrix Lam 
Mentissa Ad. 
Meroö Schum. 
Merope Alb. 
Merope Ad. 
Mesembrinus Alb. 
Mesodesma Desh. 
Mesodon Raf. 
Mesomphix Raf. 
Metaptera Raf. 
Metastoma Streb. 
Metis Ad. 
Miamira Bergh 
Microcondylaea Vest. 
Microeystina Mörch 
Microcystis Beck 
Microphysa Alb. 
Mierothyea Ad. 
Microtis Ad. 
Miltha Ad. 
Minolia Ad. 
Miodon Carp. 
Modelia Gray 
Modicella Ad. 
Modiola Lam. 
Modialarca Gray 
Modiolaria Beck 
Moelleria Jefir. 
Moera Ad. 
Moerchia Ad. 
Moercliia Alb. 
Monacha Hartm. 
Monia Gray 
Monica Ad. 
Monilea Swains. 
Monilearia Mouss. 
Monoecondylaea d’Orb. 
Monodaena Eichw. 
Megalomastoma Gldg. 
Megalophaedusa Bttg. 
358 
Monodonta Lam. 
Monopleurobranchiata. 
Monothyra Tryon 
Montacuta Turt. 
Montagua Flem. 
Montrouziera Sow. 
Monvillia Gray 
Moreletia Pfr. 
Morestia H. Ad. 
Mormus Alb 
Morrisia Davids. 
Moussonia Semp. 
Mülleria Fer. 
Mulinia Gray 
Murcia Römer 
Murella Pfr. 
Musculium Link 
Mutela Scop. 
Mya Lam. 
Mycetopus d’Orb. 
Mychopoma Bf. 
 Mylitta d’Orb. 
Myochama Stutchb. 
Myodora Gray 
Myonia H. Ad. 
| Myrina Ad. 
Myrtea Turt. 
Mysia Leach. 
Mytilimeria Conrad 
Mytilus L! 
| Rracella Schu 
Najadea Ad. 
Nanina Alb 
Napaeus Alb. 
Natere Gray 
Nausitoria Wrisht 
Nauta Leach 
Nautilinus Mouss. 
Navicella Humphr. 
Navicula Spix. 
Neaera Gray 
Neda Ad 
Neilo Ad 
Nenia Ad. 
Neniatlanta Bgt. 
Neolepton Mtrs. 
Nerea Less. 
Nerita L. 
Neritaea Roth 
Neritilia Mart. 
Neritina Lam. 
Neritodryas Mart. 
Neritona Mart. 
Neritopsis Grat. 
Nesiotus Alb. 
Nesis Mtrs. 
Nesa Ad. 
Nettastomella Carp. 
Newcombia Ad. 
Nicania Leach 
Nieida Blfd. 
Nigritella Mart. 
Ninella Gray 
Noötia Gray 
Nona Ad. 
| Notarchus Cuv. 
Nothus Alb. 
Notodoris Bergh 
Novaculina Bens. 
Nucula Lam. 
Nummulina Kob. 
@dbba Beck 
Obeliseus Beck 
Ochthephila Beck 
Odontartemon Pfr. 
Odontoeyelas Schlüt. 
Odontosagda Mart. 
Odontostomus Beck 
Odontura Ürosse 
Oedalia Carp. 
' Oithona Ald. 
Olana Ad 
Oleacina Bolten 
Oligoptychia Bttg. 
Oligyra Say 
Olympia Vest. 
Omalonyx d’Orb. 
Omphalius Phil. 
Omphalina Raf. 
Omphalostyla Alb. 
Omphalotropis Pfr. 
Omphiscola Raf. 
Onchidella Gray 
Onchidium Buch. 
Onchidoris Blv. 
Onychoglossa 
Oopelta Mörch 
Oospira Blanf. 
 Opeas Alb. 
Opereulatum Ad. 
Ophicardelus Beck 
Ophiogyra Alb. 
Opisophthalmia 
Opisthobranchiata 
Opisthoporus Bens. 
Opisthotoma Blfd. 
Oreula Held 
Orodoris Bergh 
Orphnus Alb. 
Orpiella Gray 
Orthalieinus Crosse 
Orthalicus Beck 
Orthalyeaeus Pfr. 
ÖOrthopoma Gray 
Orthostylus Mart 
Orustia Mörch 
ÖOscanius Leach 
Ostodes Pease 
Ostrea L. 
Otavia Gray 
Otina Gray 
Otopoma Gray 
Otostomus Beck 
Ovella Pfr. 
Oxycheilus Alb 
Oxychona Mart. 
Oxyperas Mörch 
Oxystele Phil. 
Oxytes Pfr. 
Bachnodus Alb. 
Pachyotus Beck 
Pachypoma Gray 
Pachystyla Mörch 
