Limax (51 sp.), Palæarctic region, Australia and the Sandwich Islands; Anadenus (2 sp.), Himalayas; Philomychus (9 sp.), North America, China and Java; Arion (25 sp.), Norway to Spain and South Africa; Parmacella (7 sp.), South Europe, Canary Islands and North India; Janella (1 sp.), New Zealand; Aneitea (1 sp.), New Hebrides and New Caledonia; Parmarion (4 sp.), India; Triboniophorus (3 sp.), Australia; Testacella (3 sp.), South Europe, Canary Islands, and New Zealand; Hyalimax (2 sp.), Bourbon and Mauritius; Krynickia (8 sp.), Eastern Europe and North America. A few species of Limax, Arion, and Testacella have been found fossil in Tertiary deposits.
Family 24.—ONCIDIADÆ. (2 Genera, 36 Species.)
| General Distribution. | |||||
 | |||||
| Neotropical Sub-regions. | Nearctic Sub-regions. | Palæarctic Sub-regions. | Ethiopian Sub-regions. | Oriental Sub-regions. | Australian Sub-regions. |
| 1. 2. 3. 4 | — — — — | 1. 2 — — | — — — 4 | 1. 2. 3. 4 | — 2 — 4 |
The Oncidiadæ, or Slugs with a coriaceous mantle, inhabit the Oriental region, Mauritius, Australia, the Pacific Islands, South America and South Europe. The genera are:—
Oncidium (16 sp.), South Europe (1 sp. British), Mauritius, Australia and Pacific Islands; Vaginulus (20 sp.), Neotropical and Oriental regions.
Family 25.—LIMNÆIDÆ. (7 Genera, 332 Species.)
| General Distribution. | |||||
| |||||
| Neotropical Sub-regions. | Nearctic Sub-regions. | Palæarctic Sub-regions. | Ethiopian Sub-regions. | Oriental Sub-regions. | Australian Sub-regions. |
| 1. 2. 3. 4 | 1. 2. 3. 4 | 1. 2. 3. 4 | — — 3 — | 1. 2. 3. 4 | — — — — |
The Limnæidæ, or Fresh-water Snails, inhabit ponds and rivers in most parts of the world, but appear to be absent from the Australian region. The genera are distributed as follows:—
Limnæa (95 sp.), Nearctic, Palæarctic, and Oriental regions; Choanomphalos (2 sp.), Lake Baikal; Pompholyx (2 sp.), Western America; Chilinia (18 sp.), South America; Physa (20 sp.), Nearctic, Palæarctic, Ethiopian and Oriental regions, and extends to above 73° North Latitude in Siberia, being the most Arctic of land or fresh-water shells; Ancylus (49 sp.), Nearctic and Neotropical regions, Europe and New Zealand; Planorbis (145 sp.), Nearctic, Palæarctic and Oriental regions. Several genera are found fossil, chiefly in the Wealden, Eocene, and Miocene formations.
Family 26.—AURICULIDÆ. (3 Genera, 210 Species.)