ARGENTINE REGION. 405 



suails, only 7 species of B/cHmus, and 3 Helices are recorded, but some 

 others may have been included with those of Brazil and Chile. From Bolivia 

 this province is separated by the wide plains of the Great Desert, or northern 

 prolongation of the Pampas ; and all the eastern part has been submerged at 

 a recent (geological) period ; so that the only promising districts are 

 Paraguay, and the eastern declivities of the Chilian Andes. The fresh-water 

 shells of the La Plata and its tributaries are more remarkable; J\I. D'Orbigny 

 gives the following : — 



Amjmllaria (^Marisa) eomu-arietls is a characteristic shell ; Paludestrina 

 lapidi.im has a claw4ike (non-spiral) operculum, and appears to belong to the 

 3Ielaniadce. 



26. Chilian Region. 



The northern part of Chile belongs to the same physical region with Peru, 

 consisting of dry and rainless plains. Here the land snails are few and small, 

 and only seen after the dews. At Valparaiso raia is abundant during the 

 three winter months, and the southern coasts are luxuriantly wooded, and 

 extremely wet. The characteristic pulmonifera are the fresh-water Chilinias. 

 The genus Buchanania is doubtful. There are 25 sp. of Buliraus (includ- 

 ing B. Chilensis, Plectostylus) and 4 of Helix ; Succinea Chiloensis, Ancylus 

 Gayanus (Valparaiso), Planorbis fuscus, Paludestrina sp. Unio Chilensis, 

 Pisidium Chilense (Valdivia). Heli.v Binneyana is found on the Island of Chiloe. 

 The Island of Juan Fernandez (36) has at least 20 species of land shells, 

 all peculiar to it : — 



Helix quadrata Omalony.x Gayana Tornatellina minuta 



arctispira Achatina diaphana „ trochiformis 



pusio „ splendida Succinea Cumingi 



tessellata „ bulimoides „ mamillata 



ceroidps „ conifera ,, fragilis 



marmorella „ acuminata ? Pannacella Cumingi. 



helicophantoides Spiraxis consimilis 



In the adjoining Island, Masafuera, are found — 



Tornatellina Eecluzii Succinea semiglobosa 



Succinea rubicunda ,, pinguis 



27. Patagonian Region. 

 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 



T 2 



