198 LAND REGIONS. 



22. Chilian Kegion. 



The northern part of Chili 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 rain is abundant during the three winter months, and 

 the southern coasts are luxuriantly wooded and extremely wet. 

 The fauna is characterized by the abundance of Bulimi, belong- 

 ing to the sections Borus, Scutalus, Peronseus, and Plectostylus, 

 all South American groups. There are but few Helices, one of 

 which H. laxata attains a large size, and recalls b}^ its form the 

 H. lanx of Madagascar. There are only two operculated species. 

 Among the fluviatile shells Chilina and Unio are largely repre- 

 sented. One of the former and a Succinea are peculiar to the 

 island of Chiloe. The Islands of Juan Fernandez have a fauna 

 completely restricted, numbering over 20 species, all terrestrial, 

 mostly Helix and Succinea. 



23. Peruvian Region. 



The long and narrow tract between the Andes and Pacific, 

 extending from the equator to 25° S. lat. forms a distinct though 

 comparatively unproductive province, including the coast of 

 Ecuador, Peru and Bolivia. It is warm and almost rainless ; 

 the clouds discharge themselves on the east side of the Andes, 

 and rain is so rare on the west coast that in some parts it only 

 falls two or three times in a centuiy. In Peru, during great part 

 of the year, a vapor rises in the morning, called the " garua ;" it 

 disappears soon after midday, and is followed by heavy dews at 

 night. There are a few helicoid shells, some of them of very 

 peculiar appearance, but the Bulimi are predominant and include 

 many species. The reappearance here of a group of the Medi- 

 terranean genus Clausilia, with t species, is a notable fact. There 

 are 3 Helicinas. Chilina has disappeared, but there are 3 

 Ampullaria. Planorbis is well represented, as is Anodonta ; 

 besides which we find Ancylus, Limnsea, Physa, Cyclas, Cyrena. 



The fauna and fiora of the Galapagos Islands are peculiar, 

 although related to those of South America. The only known 

 shells are 18 species of Bulimus, forming the section Nesiotes ; 

 and of these, 10 species are restricted to single islands of the 

 group. 



24. Columbian Region. 



This includes the rainy and wooded States of New Granada 

 and Ecuador (except the Pacific coast of the latter), the elevated 

 and nearly rainless province of Venezuela, with a flora like that 

 of the higher regions of the Andes ; and Guiana, where the forests 

 are most luxuriant, and rain falls almost daily (amounting to 100 

 or even 200 inches in the j^ear). Most of the low lands, like 



