OCTOPODA (UNASSIGNED)
3846
2 Sp, 0 Var, 0 Img
(Sea)
(FOSSIL)

OCTOPODIDAE
3842
268 Sp, 11 Var, 49 Img
(Sea)

OCTOPOTEUTHIDAE
3762
9 Sp, 0 Var, 2 Img
(Sea)

OCYTHOIDAE
3826
1 Sp, 0 Var, 1 Img
(Sea)

ODONTOSTOMIDAE
6002
136 Sp, 16 Var, 119 Img
(Land)

OECOPTYCHIIDAE
3230
3 Sp, 0 Var, 2 Img
(Sea)
(FOSSIL)

OFFLEYOCERATIDAE
4172
1 Sp, 0 Var, 0 Img
(Sea)
(FOSSIL)

OKADAIIDAE
5728
6 Sp, 0 Var, 2 Img
(Sea)

OLCOSTEPHANIDAE
3186
65 Sp, 1 Var, 13 Img
(Sea)
(FOSSIL)

OLEACINIDAE
6082
126 Sp, 21 Var, 64 Img
(Land)

OLIVELLIDAE
5324
184 Sp, 14 Var, 145 Img
(Sea)

OLIVIDAE
5326
290 Sp, 225 Var, 227 Img
(Sea)

OMALOGYRIDAE
6156
56 Sp, 7 Var, 37 Img
(Sea)

OMMASTREPHIDAE
3764
22 Sp, 4 Var, 18 Img
(Sea)

OMNIGLYPTIDAE
8014
1 Sp, 0 Var, 1 Img
(Sea)

OMPHALOCIRRIDAE
5526
14 Sp, 0 Var, 0 Img
(Sea)
(FOSSIL)

OMPHALOTROCHIDAE
5528
55 Sp, 0 Var, 2 Img
(Sea)
(FOSSIL)

ONCHIDIIDAE
6096
111 Sp, 3 Var, 8 Img
(Sea)

ONCHIDORIDIDAE
5714
73 Sp, 7 Var, 27 Img
(Sea)

ONCOCERATIDAE
4128
73 Sp, 0 Var, 14 Img
(Sea)
(FOSSIL)

ONCOCERIDA (UNASSIGNED)
4142
55 Sp, 0 Var, 15 Img
(Sea)
(FOSSIL)

ONYCHOCHILIDAE
9804
36 Sp, 0 Var, 7 Img
(Sea)
(FOSSIL)

ONYCHOTEUTHIDAE
3766
48 Sp, 0 Var, 9 Img
(Sea)

OONOCERATIDAE
4130
8 Sp, 1 Var, 2 Img
(Sea)
(FOSSIL)

OOPELTIDAE
5884
4 Sp, 0 Var, 2 Img
(Land)

OOSTERELLIDAE
3188
8 Sp, 0 Var, 2 Img
(Sea)
(FOSSIL)

OPHICERATIDAE
3344
19 Sp, 0 Var, 0 Img
(Sea)
(FOSSIL)

OPHIDIOCERATIDAE
4160
3 Sp, 0 Var, 1 Img
(Sea)
(FOSSIL)

OPHILETIDAE
5534
80 Sp, 0 Var, 21 Img
(Sea)
(FOSSIL)

OPISTHOBRANCHIA (UNASSIGNED)
5828
10 Sp, 0 Var, 6 Img
(Sea)
(FOSSIL)

OPISTHONEMATIDAE
5536
1 Sp, 0 Var, 0 Img
(Sea)
(FOSSIL)

OPISTHOTEUTHIDAE
3820
38 Sp, 0 Var, 5 Img
(Sea)

OPPELIIDAE
3146
207 Sp, 3 Var, 94 Img
(Sea)
(FOSSIL)

ORBITESTELLIDAE
5576
32 Sp, 0 Var, 10 Img
(Sea)

ORCULIDAE
5978
72 Sp, 38 Var, 49 Img
(Land)

OREOHELICIDAE
6046
53 Sp, 21 Var, 22 Img
(Land)

ORIOCRASSATELLIDAE
2020
12 Sp, 0 Var, 1 Img
(Sea)
(FOSSIL)

ORIOSTOMATIDAE
6244
120 Sp, 1 Var, 3 Img
(Sea)
(FOSSIL)

ORMOCERATIDAE
3930
24 Sp, 0 Var, 1 Img
(Sea)
(FOSSIL)

ORNITHOPECTINIDAE
2668
6 Sp, 0 Var, 0 Img
(Sea)
(FOSSIL)

ORTHALICIDAE
6004
119 Sp, 155 Var, 187 Img
(Land)

ORTHOCERATIDAE
4216
122 Sp, 2 Var, 37 Img
(Sea)
(FOSSIL)

ORTHOCERIDA (UNASSIGNED)
4230
17 Sp, 0 Var, 3 Img
(Sea)
(FOSSIL)

ORTHONEMATIDAE
5452
40 Sp, 0 Var, 3 Img
(Sea)
(FOSSIL)

ORTHONEMIDAE
5058
60 Sp, 0 Var, 4 Img
(Sea)
(FOSSIL)

ORTHONOTIDAE
2340
12 Sp, 1 Var, 6 Img
(Sea)
(FOSSIL)

ORTHONYCHIIDAE
6238
65 Sp, 0 Var, 4 Img
(Sea)
(FOSSIL)