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NATURALIST'S GUIDE TO THE AMERICAS 



in those parts of Venezuela where the 

 mountains are some distance back from 

 the coast, the streams flow through wide, 

 almost level flood-plains of alluvial 

 deposit, which, during the wet season, 

 must be largely under water or dis- 

 sected by innumerable streams. The 

 edaphic influence of this rich soil, 

 containing ground water near the sur- 

 face, permits the development of large 

 and rich forests, even in the lowlands 

 where the rainfall is not great enough 

 to account for their presence. 



Although in some localities, large 

 plantations have been cleared of the 

 smaller trees and brush, the unhealthi- 

 ness of these lowlands has resulted in 

 a very sparse population. Where large 

 clearings have been made, irrigation is 

 often necessary; when abandoned, such 

 places commonly assume the appear- 

 ance of rich prairie, and the woodland 

 appears to invade the sun-baked surface 

 with some difficulty. Small clearings 

 become overgrown with remarkably 

 dense growths of Heliconiae and Con- 

 volvuli and revert to forest in a few 

 years. 



In these lowland forests, tapir (Tapi- 

 rus americanus), peccaries (Tayassu 

 tajacu), howler-monkeys (Alouata seni- 

 culus, etc.), and the chigiiire (Hydro- 

 choerus capybara) are especially abun- 

 dant. The larger parrots (Ara, Conu- 

 TUS, etc.), troupials (Cassicus), and 

 toucans (Ramphastus, etc.) are more 

 conspicuous members of the avifauna, 

 although, as a rule, this appears more 

 monotonous than in the mountains. 

 Where a leaf-humus is developed, the 

 molluscan fauna is very rich; amongst 

 the larger ground forms, Pleurodonte 

 is conspicuous in central Venezuela, 

 but is replaced by Plekocheilus in 

 Estado Tachira. Near streams, the 

 forest mainly consists of palms, which 

 develop very little true humus; in 

 swampy places, almost pure stands of 

 Bactrideae often form dense, impene- 

 trable thickets. In such places, only 

 the arboreal species (Drymaeus, Auris} 

 are represented. 



Alonj the high banks of the larger 



streams, the soil is often sandy and 

 covered by a dense cane-brush or more 

 rarely by bamboo-thickets; ground liz- 

 ards (Ameiva) are especially abundant 

 in these places. Although Ampullarius 

 is abundant and freshwater pulmonates 

 occur in the pools and canos (Neoneura 

 is characteristic among the Odonata), 

 the larger streams are remarkably 

 barren, perhaps on account of their 

 frequent scourings; the extreme paucity 

 of Naiades is especially noticeable. 



Luxuriant tropical rain-forest (H. B. 

 #.). In undisturbed portions of the 

 Caribbean System, the arid coastal 

 region passes quite rapidly into the 

 rain-forest, which, in places, reaches 

 down to an altitude of less than a hun- 

 dred meters. Like most tropical for- 

 ests, the most noticeable feature is the 

 variety in size of the trees and in the 

 floristic composition; large stands of a 

 single or a few dominant species are 

 conspicuous by their absence. In gen- 

 eral, the trees do not attain a very 

 great height, and even the ceibas are 

 less gigantic than in western Venezuela. 

 Epiphytes are quite abundant through- 

 out this type of forest; the bromeliads 

 are especially conspicuous, but the 

 lianas and climbing arums and figs are 

 less conspicuous than in the far more 

 luxuriant Mexican rain-forest or in 

 even that of the eastern foot-hills of 

 the Andes. 



Although coffee and cacao plantations 

 encroach considerably on the native 

 forests, in most places on the north- 

 facing slopes these are so rich and ever- 

 green as to discourage any efforts to 

 burn them away. The land is usually 

 cleared by chopping out the brush and 

 leaving the larger trees. Such places 

 return to heavy forest in a few years, 

 and the leaf-humus is often richer and 

 the ground fauna more abundant in 

 "montado" coffee plantations than in 

 the original forest. 



Among the larger animals, agouti 

 (Agouti para, Dasyprocta rubratra and 

 prymnolopha] , jaguars (Felis onqa} and 

 spider monkeys (A teles} are especially 

 abundant. The bird fauna is one of 



