| belgium | | littorina littorea | species | 5 | 0 |
| canada | | littorina littorea | species | 18 | 0 |
| canada | british columbia | littorina plena | species | 3 | 0 |
| canada | british columbia | littorina scutulata | species | 30 | 0 |
| canada | british columbia | littorina sitkana | species | 42 | 0 |
| canada | manitoba | littorina saxatilis | species | 23 | 0 |
| canada | new brunswick | littorina littorea | species | 108 | 0 |
| canada | new brunswick | littorina obtusata | species | 8 | 0 |
| canada | new brunswick | littorina saxatilis | species | 6 | 0 |
| canada | newfoundland and labrador | littorina littorea | species | 105 | 0 |
| canada | newfoundland and labrador | littorina obtusata | species | 1 | 0 |
| canada | newfoundland and labrador | littorina saxatilis | species | 2 | 0 |
| canada | nova scotia | littorina littorea | species | 48 | 0 |
| canada | nova scotia | littorina obtusata | species | 23 | 0 |
| canada | nova scotia | littorina saxatilis | species | 13 | 0 |
| canada | prince edward island | littorina littorea | species | 2 | 0 |
| canada | prince edward island | littorina saxatilis | species | 14 | 0 |
| canada | quebec | littorina littorea | species | 3 | 0 |
| china | | littorina brevicula | species | 9 | 0 |
| china | guangdong | littorina brevicula | species | 58 | 0 |
| china | hunan | littorina brevicula | species | 29 | 0 |
| china | jiangsu | littorina brevicula | species | 212 | 0 |
| china | shandong | littorina brevicula | species | 108 | 0 |
| china | zhejiang | littorina brevicula | species | 48 | 0 |
| denmark | | littorina littorea | species | 32 | 0 |
| france | | littorina littorea | species | 23 | 0 |
| france | basse-normandie region | littorina littorea | species | 2 | 0 |
| france | bretagne region | littorina littorea | species | 85 | 0 |
| france | bretagne region | littorina obtusata | species | 1 | 0 |
| greenland | | littorina saxatilis | species | 1 | 0 |
| ireland | | littorina littorea | species | 8 | 0 |
| ireland | connaught province | littorina littorea | species | 28 | 0 |
| ireland | munster province | littorina littorea | species | 10 | 0 |
| japan | | littorina horikawai | species | 4 | 0 |
| japan | | littorina sitkana | species | 17 | 0 |
| japan | aichi prefecture | littorina brevicula | species | 1 | 0 |
| japan | aomori prefecture | littorina brevicula | species | 13 | 0 |
| japan | chiba prefecture | littorina brevicula | species | 11 | 0 |
| japan | fukui prefecture | littorina brevicula | species | 6 | 0 |
| japan | hiroshima prefecture | littorina brevicula | species | 4 | 0 |
| japan | hokkaido prefecture | littorina brevicula | species | 19 | 0 |
| japan | hokkaido prefecture | littorina sitkana | species | 24 | 0 |
| japan | hyogo prefecture | littorina brevicula | species | 1 | 0 |
| japan | kagoshima prefecture | littorina brevicula | species | 11 | 0 |
| japan | kanagawa prefecture | littorina brevicula | species | 10 | 0 |
| japan | oita prefecture | littorina brevicula | species | 4 | 0 |
| japan | shizuoka prefecture | littorina brevicula | species | 1 | 0 |
| netherlands | | littorina littorea | species | 5 | 0 |
| netherlands | zeeland province | littorina littorea | species | 0 | 2 |
| norway | | littorina littorea | species | 5 | 0 |
| norway | more og romsdal county | littorina saxatilis | species | 0 | 1 |
| norway | sor-trondelag county | littorina littorea | species | 73 | 0 |
| norway | troms county | littorina arcana | species | 4 | 0 |
| norway | troms county | littorina compressa | species | 3 | 0 |
| norway | troms county | littorina fabalis | species | 1 | 0 |
| norway | troms county | littorina littorea | species | 32 | 0 |
| norway | troms county | littorina obtusata | species | 15 | 0 |
| norway | troms county | littorina saxatilis | species | 5 | 0 |
| portugal | viana do castelo district | littorina obtusata | species | 2 | 0 |
| portugal | viana do castelo district | littorina saxatilis | species | 3 | 0 |
| russia | | littorina littorea | species | 21 | 0 |
| russia | | littorina sitkana | species | 5 | 0 |
| south korea | | littorina brevicula | species | 1 | 0 |
| spain | | littorina littorea | species | 5 | 0 |
| spain | | littorina saxatilis | species | 5 | 0 |
| spain | | littorina sp. f1c2 | species | 1 | 0 |
| spain | galicia | littorina fabalis | species | 1 | 0 |
| spain | galicia | littorina littorea | species | 33 | 0 |
| spain | galicia | littorina obtusata | species | 1 | 0 |
| spain | galicia | littorina saxatilis | species | 101 | 0 |
| sweden | | littorina fabalis | species | 5 | 0 |
| sweden | | littorina littorea | species | 6 | 0 |
| sweden | | littorina obtusata | species | 1 | 0 |
| sweden | | littorina saxatilis | species | 2 | 0 |
| sweden | vastra gotaland | littorina littorea | species | 16 | 0 |
| united kingdom | | littorina littorea | species | 18 | 0 |
| united kingdom | england | littorina littorea | species | 34 | 3 |
| united kingdom | england | littorina obtusata | species | 5 | 0 |
| united kingdom | england | littorina saxatilis | species | 281 | 1 |
| united kingdom | scotland | littorina littorea | species | 84 | 0 |
| united kingdom | wales | littorina littorea | species | 0 | 1 |
| united states | | littorina keenae | species | 1 | 0 |
| united states | | littorina littorea | species | 37 | 0 |
| united states | | littorina scutulata | species | 1 | 0 |
| united states | alaska | littorina sitkana | species | 10 | 0 |
| united states | california | littorina keenae | species | 4 | 0 |
| united states | california | littorina plena | species | 5 | 0 |
| united states | maine | littorina littorea | species | 27 | 0 |
| united states | maine | littorina obtusata | species | 1 | 0 |
| united states | massachusetts | littorina littorea | species | 19655 | 0 |
| united states | new hampshire | littorina littorea | species | 4 | 0 |
| united states | new york | littorina littorea | species | 3 | 0 |
| united states | virginia | littorina saxatilis | species | 3 | 0 |