221 



this group are but feebly exercised. They exist for many months together 

 in the crevices of rocks in a state of torpidity, and are only roused during 

 the excessive clews. " Wait till the dews come/' said a Chilian one day 

 to Mr. Cuming, " and they will all come to life again." 



In the warmer, but still comparatively rainless district of Peru, the 

 Bulimi have more brightly-coloured shells, with more variety of pattern. 

 They are about as numerous in species as those of Chili, under as many 

 types. In the more arid parts of Peru, upon the mountains, the shell is 

 thin, as in B. varians, tlgris, lemniscatus, and tumid iilus, compared with 

 those inhabiting more woody districts on the eastern side of the Andes. 

 They have, moreover, a colder aspect than those, of the same latitude in 

 Brazil, on account of the more scanty nature of the vegetation, the lesser 

 humidity of the atmosphere, and the cold precipitated from the ant- 

 arctic drift current which flows in a northerly direction along the western 

 shores of South America nearly to the equator. The effect of moisture 

 and consequent amount of decaying vegetable matter in promoting the 

 formation of shell is curiously illustrated by the presence of a stout 

 richly-coloured species of large size, B. p/iasianellus, on the rainy border 

 of Peru, where they crawl up the stripped trees in great abundance ; and 

 by the B. Tupacii, dwelling on bushes and garden walls on the Bolivian 

 side of the Andes at an elevation of 9,000 feet, which has a robust dark- 

 painted shell similar to those of the equally lofty Venezuelan type. B. ro- 

 saceus, which inhabits a wide range of country, extending from the environs 

 of Valparaiso, near the sea, to Cocapata in Bolivia, crouches under stones in 

 the sand in the first-named locality, and has a pale, smooth, calcareous shell. 

 But in the woods of Cocapata, where it lives in more humid situations 

 among the trunks of trees, the shell is larger, stouter, more richly coloured, 

 and with more of epidermis. Thus we have the change which charac- 

 terizes different species, presented in the same species under different con- 

 ditions. Another remarkable instance is presented in B. zebra. This 

 species inhabits an area of Central America enclosing Honduras, Nicaragua, 

 the West Indies, and Pernambuco, reaching to the shores of Peru, and 

 produces a shell varying so much in character according to the physical 

 conditions under which it is formed, that it has been described as several 

 species. The same thing has occurred with B. rtgina, which in its range 

 from New Granada and Guayaua to Bolivia and the interior of Peru, 

 affects a condition partaking in each instance of the local conchological 

 character of the country. 



4. The Bolivian Province. 



Prom Bolivia and the Argentine Republic about forty Bulimi are de- 

 scribed, illustrative of six types. The large Brazilian B. ovatus, living near 

 the coast, is here represented in the heart of the continent, at Santa Cruz, 



