Diplommatina (18 sp.) inhabits India to Burmah, and the greater part of the Australian region; the number of species has now been doubled, and one has been discovered in the island of Trinidad; Clostophis (1 sp.), Moulmein; Paxillus (3 sp.), Borneo, Hong Kong, and Loo Choo Islands.
Family 29.—CYCLOSTOMIDÆ. (41 Genera, 1009 Species.) (1865.)
| General Distribution. | |||||
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| Neotropical Sub-regions. | Nearctic Sub-regions. | Palæarctic Sub-regions. | Ethiopian Sub-regions. | Oriental Sub-regions. | Australian Sub-regions. |
| — 2. 3. 4 | — — 3 — | — — — 4 | — — 3. 4 | 1. 2. 3. 4 | 1 — — — |
This extensive group, comprising the largest of the operculated land-shells, is especially characteristic of the Oriental region, which possesses 25 genera, no less than 12 of them being wholly confined to it. The Neotropical region comes next, with 15 genera, 9 of which are peculiar; but a large number of these are confined to the West Indian Islands, South America itself being very poor in this group. The Palæarctic region has 3 peculiar genera; the Ethiopian and Australian 1 each. The Nearctic region has but a single West Indian species in Florida. The distribution of the genera is as follows:—
Peculiar to or characteristic of the Oriental region are, Opisthoporus (11 sp.), Rhiostoma (6 sp.), Alycaeus (39 sp.), Opisthostoma (1 sp.), Hybocistis (3 sp.), Pterocyclos (19 sp.), extending to the Moluccas; Aulopoma (4 sp.), Dermatocera (4 sp.), Leptopoma (54 sp.), extending west to the Seychelles and east to the Moluccas and New Guinea; Cyclophorus (163 sp.), most abundant in the Oriental region, but ranges to Japan, to Chili, and all Tropical America, over the whole Australian region, and to Natal and Madagascar; Cataulus (15 sp.), confined to Ceylon, the Neilgherries and Nicobar Islands; Rhaphaulus (4 sp.), Penang to Ceram; Streptaulus (1 sp.), Arinia (3 sp.), Pupinella (2 sp.), Pupina (24 sp.), half in North India to Philippines and Japan, the other half in Moluccas, New Guinea and Australia; Cyclotopsis (2 sp.), India and Malaya; Registoma (9 sp.), Philippines and Moluccas, New Caledonia and Pacific.
Characteristic of the Neotropical region are:—Cyclotus (111 sp.), half in the Antilles and Tropical America, the rest in the Moluccas, China, Malaya, India, Natal, and the Seychelle Islands; Megalomastoma (27 sp.), abundant in Cuba, West Indies and South America, others in India, Malaya, and Mauritius; Jamaicia (2 sp.), Jamaica; Licina (5 sp.), Antilles; Choanopoma (49 sp.), Antilles; Ctenopoma (25 sp.), Antilles; Diplopoma (1 sp.), Cuba; Adamsiella (15 sp.), Jamaica, Cuba, Guatemala; Cyclostomus (113 sp.), abundant in Antilles, also occurs in Madagascar, Arabia, Syria, Hungary and New Zealand; Tudora (34 sp.), Antilles, and one species in Algeria; Cistula (40 sp.), Chondropoma (94 sp.), Bourcieria (2 sp.), Tropical America.
Peculiar to or characteristic of the Palæarctic region are:—Craspedopoma (5 sp.), confined to Madeira, the Azores and Canaries; Leonia (1 sp.), Spain and Algeria; Pomatias (22 sp.), Europe and Canaries with a species in the Himalayas; Cecina (1 sp.), Manchuria.
The Ethiopian region has the peculiar genus Lithodion (5 sp.), Madagascar, Socotra and Arabia; and Otopoma (19 sp.), Mascarene Islands and Socotra, with a species in Western India and another in New Ireland.
The Australian region is characterised by Callia (3 sp.), in Ceram, Australia, and the Philippines respectively; Realia (7 sp.), New Zealand and the Marquesas Islands; Omphalotropis (38 sp.), the Australian region, with some species in India, Malaya, and the Mauritius.
The remaining genus, Hydrocena (27 sp.), has a very widely scattered distribution, being found in South Europe, Japan, the Cape, China, Malaya, New Zealand, the Pacific Islands and Chili. From 10 to 20 per cent. of new species have been since described in most of the genera of this family.