LAND REGIONS. 197 



and with New Caledonia in that of Placost^ins, Melanopsis and 

 Rhytida. The genns Latia is pecnliar. The moist and equable 

 climate of these islands, which have a mean temperature of 61° 

 -63°, is favorable to the existence of numerous land snails. The 

 heliciform species number 58, whilst the operculates include 

 only two Cyclophorus, a Paxillus, Diplommatina, Realia, etc. 

 There is a Phj^sa of the Australian group Ameria, 5 Fnionidse, 

 and a Potamopyrgus or spiny Hj'drobia, resembling West Indian 

 and South American species. Hutton's catalogue of the land 

 and fresh-water species, published in 1880, contains 128 names. 

 The genus Partula is not represented. The Aueklands, Campbell, 

 Norfolk and Kermaudec Isles belong to this Province, but each 

 contains one or more special species. 



21. Patagonian Region. 



Fischer very properly unites under this name the Argentine 

 and Patagonian Regions of Woodward. The region is an exten- 

 sive one, yet the fauna is very meagre, including only 114 species ; 

 79 being terrestrial, of which not a single one is operculated. 

 More than half the species are fluviatile. The physical condition 

 of these countries explains the anomalous distribution of the 

 mollusca. The pampas, or great plains of Patagonia, are dry 

 and rainless nearly all the year ; the vegetation which springs 

 up during the light summer rains, becomes converted into natural 

 hay for the support of the wild animals. In Fuegia the mean 

 temperature is 33°-50°, and there is rain and snow throughout 

 the year ; yet the bases of the mountains are clothed with forests 

 of evergreen beech. The fertile portion of the Argentine States 

 is separated from Bolivia by the wide plains of the Grreat Desert 

 or northern prolongation of the pampas ; and all the eastern part 

 has been submerged at a recent geological period ; the only 

 promising districts are Paraguay and the eastern declivities of 

 the Chilian Andes. 



The characteristic terrestrial forms are Bulimi, with apertures 

 contracted by teeth, sections Plagiodontes, Odontostomus, and 

 Macrodontes ; Chilina, a fresh-water pulmonate allied to Limnsea, 

 but with toothed aperture, and peculiar to South America, 

 furnishes 5 species ; the bivalve genus Monocondylasa, also 

 South American in distribution, has 5 species ; there are 24 

 Unio, 11 Anodonta, and species of the related South American 

 genera Leila, Castalia, Mycetopus, Byssanodonta. Azai^a labiata, 

 an estuary shell related to Corbula, is found in the La Plata 

 River, Of fresh-water gastropods, Planorbis has 6 sp , Ampul- 

 laria 9 sp., Paludestrina 11 sp. No Melania or Paludina. The 

 Falkland Islands are 300 miles east of Patagonia. The only 

 recorded shells are 2 species of Paludestrina. A single species, 

 Helix Hookeri inhabits Kerguelen Island. 



