SANDWICH ISLANDS 327 



and obscure. Helix scarcely occurs, its place being taken by 

 small Zonitidae (^Microcystis^ Charopa^ Trochomorpha^ etc.), and 

 by groups of so-called Patula QEndodonta^ Pitys^ etc.), the exact 

 position of which is not yet settled. Libera^ remarkable for its 

 method of ovipositing (p. 128), is peculiar to the Society and 

 Hervey Is. ; Partula is almost universal, attaining its maximum 

 (40 sp.) in the Society Is. ; Tornatellina^ Pupa^ and Vertigo occur 

 throughout. 



The land operculates consist chiefly of Omphalotropis, Pupina, 

 Bealia, and Helicina. Diplommatina and Palaina are abundant 

 on the Pelews, and a Moussonia occurs in the Samoa Is. Ostodes, 

 a small form of Cyclophorus, is found in some of the southern 

 groups. The fresh-water operculates are Melania, Neritina 

 (including Olithon, a sub-genus furnished with spines), and 

 JVavicella ; there are no Unionidae, while fresh- water Pulmonata 

 are very scarce. 



(6) The land MoUusca of the Hawaiian province are distin- 

 guished by the possession of four entirely peculiar genera — 

 Achatinella^ Leptachatina^ Carelia^ and Auriculella. More than 

 300 of the two former genera have been described, every moun- 

 tain valley of some of the islands having its own peculiar species. 

 The destruction of the indigenous herbage by goats is rapidly 

 extinguishing many forms. Partula^ and the small land oper- 

 culates, so characteristic of the other groups, are, with the excep- 

 tion of Helicina^ entirely wanting. The occurrence of one of 

 the Merope group of Helix (Solomon Is.) is remarkable, and 

 there is a rich development of Succinea. " Patula^^ Microcystis^ 

 Tornatellina^ and the other small Polynesian land Pulmonata 

 are well represented. The presence of Isidora, absent from the 

 central Pacific groups, is remarkable, and Hrinna is a peculiar 

 genus belonging to the Limnaeidae. 



