POLYNESIAN REGION. 105 



they are chiefly, perhaps entirely, colonised by drift from the 

 other islands. 



The volcanic groups are the Ladrones, Sandwich Islands, and 

 Marquesas, to the north of the low coral zone ; and to the south 

 of it, the Salomons, New Hebrides, New Caledonia, andFeejees 

 — the Friendly Islands, Navigator's and Cook's Islands — Society 

 and Austral Islands, ending with Pitcairn's and Elizabeth 

 Island. Many of these are very lofty. Their molluscan fauna 

 is entirely peculiar, but it has most affinity with those of New 

 Zealand and the Asiatic Islands, and great analogy with those 

 of St. Helena, Brazil, and the West Indies. 



Salomons — New Hebrides — JSfew Caledonia — Feejeee, 



The most remarkable land- shells of these islands are the great 

 auriculoid, Bidimi (e.g. B. auris-hovinee and B. miltochlius of 

 the SalomoQs). Acicula striata and 2 sp. of Cyrena are found 

 at Vanicoro ; and Physa sinuata, JPeronia acinosa and corpulenta, 

 and several Neritinas and coronated Melanias, have been ob- 

 tained at the Feejees.* 



10 Cyclophorus 2 



6 Omphalotropis 1 



1 Helicina 6 



Friendly Islands — Navigator's — Society Islands. 



The principal lofty and rocky islands of the southern Pacific, 

 at which land shells have been obtained, are Tonga, Samoa, 

 Upolu, and Manua ; Tahiti, Oheteroa, and Opara ; Pitcairn's 

 Island and Elizabeth Island. Each appears to have some pecu- 

 liar species and some common to other islands ; the little raised 

 coral islet Aurora {Metia), north-east of Tahiti, 250 feet in ele- 

 vation, has four land-snails which have been found nowhere 

 else — Helix pertenuis, dcedalea, Partula pusilla, Helicina trochlea. 

 " Samoa and the Friendly Islands must have intimate geo- 

 logical relations ; the same forms, and many of the same species 

 of land shells, occur on both groups ; not a single Feejeean 

 species was collected on either." (Gould.) 



Helix 13 Tornatellina 6 Cyclophorus 6 



Nanina 18 Pupa 3 Omphalotropis 6 



Bulimus 1 Succinea 12 Helicina 13 



Partula 15 Electrina 1 



The fluviatile shells are species of Physa, Melania, Assiminea 



* The Feejees {Viti) are more nearly allied to the westward islands, such as the 

 New Hebrides, than the Friendly Islands. Succinea and Partula, so plentiful at the 

 latter, are not found at the Feejees. (Gould, U.S. Exploring Expedition). 



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