Land and Fresh-water Mollusca of New Guinea
| Rhytida | 1 |
| Helicarion | 2 |
| Rhysota | 1 |
| Hemiplecta | 11 |
| Xesta | 2 |
| Microcystis | 3 |
| Microcystina | 2 |
| Sitala | 2 |
| Oxytes (?) | 2 |
| Conulus | 1 |
| Trochomorpha | 8 |
| Nanina (?) | 3 |
| Charopa | 1 |
| Thalassia | 3 |
| Ochthephila(?) | 1 |
| Chloritis | 13 |
| Planispira | 5 |
| Cristigibba | 9 |
| Insularia | 17 |
| Obbina | 1 |
| Albersia | 3 |
| Hadra | 4 |
| Pedinogyra | 1 |
| Papuina | 35 |
| Corasia (?) | 1 |
| Bulimus (?) | 1 |
| Calycia | 4 |
| Partula | 3 |
| Pupa | 1 |
| Stenogyra | 1 |
| Tornatellina | 1 |
| Perrieria | 1 |
| Succinea | 1 |
| Vaginula | 1 |
| Limnaea | 2 |
| Isidora | 3 |
| Melania | 28 |
| Faunus | 1 |
| Vivipara | 4 |
| Diplommatina | 1 |
| Pupina | 4 |
| Pupinella | 3 |
| Omphalotropis | 2 |
| Bellardiella | 2 |
| Leptopoma | 16 |
| Cyclotus | 5 |
| Cyclotropis | 5 |
| Helicina | 15 |
| Unio | 4 |
| Cyrena | 3 |
| Corbicula | 1 |
| Batissa | 8 |
Waigiou is practically a part of New Guinea. Twelve genera and twenty species of Mollusca are known, eight of the latter being peculiar. The occurrence of Papuina, Insularia, and Calycia sufficiently attest its Papuan relationship. Two species each of Albersia, Chloritis, and Planispira occur.[372]
The Aru Is. are, as we should expect from their position, and particularly from the configuration of the adjacent sea bottom (see map), markedly Papuan. At the same time they show unmistakable signs of long-continued separation from the parent island, for of their 36 land Mollusca 15, and of their 20 fresh-water Mollusca 9 are peculiar. The Papuan element consists in the presence of Papuina, Albersia, and Cristigibba. Moluccan influence is not absent, for the three Helicina, the Albersia, and one Cyclotus are all Moluccan species. The fresh-water fauna appears to be a mixture of varied elements. The single Segmentina is common to India, the Glaucomya to Malacca and the Philippines, while the single Batissa is also found in New Zealand.
Land and Fresh-water Mollusca of the Aru Islands
| Xesta | 4 |
| Microcystis | 1 |
| Hyalinia(?) | 1 |
| Trochomorpha | 1 |
| Patula | 1 |
| Eulota | 1 |
| Chloritis | 5 |
| Cristigibba | 2 |
| Albersia | 1 |
| Papuina | 4 |
| Pupa | 2 |
| Stenogyra | 2 |
| Planorbis | 1 |
| Segmentina | 1 |
| Melania | 14 |
| Leptopoma | 3 |
| Moussonia | 1 |
| Realia | 1 |
| Cyclotus | 3 |
| Helicina | 3 |
| Cyrena | 2 |
| Glaucomya | 1 |
| Batissa | 1 |
The Louisiades, the d’Entrecasteaux, and Trobriand Is., and Woodlark I., are closely related to New Guinea, containing no peculiar genera. Each group, however, contains a considerable proportion of peculiar species, an indication that their separation from New Guinea dates from a very distant period. From the Louisiades are known 34 species in all, 22 of which are peculiar.
The fauna of the Admiralty Is., of New Hanover, and New Ireland is markedly Papuan, without any especial feature of distinction. The Admiralty Is. contain 15 sp. Papuina, 7 Chloritis, 1 Planispira, and 1 Corasia. A single Janella shows relationship with the New Hebrides and with New Zealand. In New Ireland Planispira (which is specially characteristic of W. New Guinea and the Moluccas) has disappeared, but there are 7 Papuina and 6 Chloritis. The essentially Polynesian Partula is present in both groups.
The prominent feature of the Mollusca of the Solomon Is. is the extraordinary development of Papuina, which here culminates in a profusion of species and singularity of form. The genus is arboreal, crawling on the branches and attaching itself to the leaves of trees and underwood. Of the 140 land Pulmonata known from the group, no less than 50, or 36 per cent, are Papuina. Ten species of Corasia occur, but whether the shells so identified are generically identical with those of the Philippines, is not satisfactorily determined. Trochomorpha, with 22 species, here attains its maximum. Chloritis begins to fail, but still has 3 species. Indo-Malay influence still appears, though feebly, in Hemiplecta (3), Xesta (1), and possibly even Macrochlamys (1). The Rhytida, the 3 Hadra, and possibly the Paryphanta represent the Australian element. The growing numbers of Partula (13), the small and inconspicuous land operculates (only 22 in all, with Helicina very prominent), and the almost complete absence of fresh-water bivalves, show signs of strong Polynesian affinities. An especial link with the New Hebrides, New Caledonia, and the Viti Is. is the occurrence of Placostylus (16 sp.). It is very remarkable that this genus should occur in the Solomon Is. and not in New Ireland. The occurrence of Streptaxis, if authentic, is very noteworthy, the nearest species being from the Philippines.
Land and Fresh-water Mollusca of the Solomon Islands