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 Pahila {Endodonta, 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. ; Partido is almost universal, attaining its maximum 

 (40 sp.) in the Society Is.; TornatcUinct, Pupa, and Vertigo occur 

 throughout. 



The land (jperculates consist chiefly of Omplicdotropis,Pnpina, 

 Recdia, and Helicina. Dipdoynmatina and Palaina. are abun- 

 dant on the Pelews, and a Monssonia 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 Clithon, a sub-genus furnished with spines), 

 and JSfaviccUa ; there are no Unionidae, while fresh -water 

 Pulmonata are very scarce. 



(h) The land Mollusca of the Haicaiian pirovince are dis- 

 tinguished by the possession of four entirely peculiar genera — 

 Aehatinella, Leptachatinct, Carelia, and Anricidella. 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. Partida, and the small land oper- 

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

 exception of Helicina, entirely wanting. The occurrence of one 

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

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

 Tornxitelliiia, and the other small Polynesian land Pidmonata 

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

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

 senus belonging to the Linmaeidae. 



