| General Distribution. | |||||
 | |||||
| Neotropical Sub-regions. | Nearctic Sub-regions. | Palæarctic Sub-regions. | Ethiopian Sub-regions. | Oriental Sub-regions. | Australian Sub-regions. |
| 1 — — 4 | 1. 2. 3. 4 | 1. 2 — — | 1. 2. 3 — | 1. 2. 3. 4 | 1. 2 — 4 |
The Auriculidæ are chiefly found near the sea in hot countries, and are most abundant in the Eastern tropics. They are absent from the East coast of South America. The genera have a somewhat restricted distribution as follows:—
Auricula (128 sp.), India, Pacific Islands, Peru and West Indies; Melampus (56 sp.), West Indies and Europe; Carychium (9 sp.), Europe and North America; Plectrotrema (14 sp.), Australia, Malay Islands, China, Cuba; Blauneria (2 sp.), West Indian and Sandwich Islands. There are many fossil species ranging back to the Eocene formation.
Family 27.—ACICULIDÆ. (4 Genera, 65 Species.) (1865.)
| General Distribution. | |||||
| |||||
| Neotropical Sub-regions. | Nearctic Sub-regions. | Palæarctic Sub-regions. | Ethiopian Sub-regions. | Oriental Sub-regions. | Australian Sub-regions. |
| — 2. 3. 4 | 1. 2 — — | 1. 2 — 4 | — — — 4 | — 2 — 4 | 1. 2. 3 — |
The Aciculidæ are small cylindrical shells chiefly found in the West Indian Islands, but with representatives widely scattered over the globe.
Acicula (5 sp.) is European only; Geomelania (21 sp.), and Chittya (1 sp.), are confined to the Island of Jamaica; Truncatella (38 sp.), is most abundant in the Antilles, but is also found in some part of each of the six regions, as indicated by the diagram of the family. But few new species have been added to this group.
Family 28.—DIPLOMMATINIDÆ. (3 Genera, 23 Species.) (1865.)
| General Distribution. | |||||
| |||||
| Neotropical Sub-regions. | Nearctic Sub-regions. | Palæarctic Sub-regions. | Ethiopian Sub-regions. | Oriental Sub-regions. | Australian Sub-regions. |
| — 2 — — | — — — — | — — — — | — — — — | 1 — 3. 4 | 1. 2. 3. 4 |
The Diplommatinidæ are minute shells of the Oriental and Australian regions.