272 Mr. L. Reeve on the Habits and 



through it ; as the moisture evaporates, the epidermis resumes its 

 light appearance. Sir David Brewster, in reply to a letter from 

 Mr. Broderip on this subject, says : " It appears to me, from 

 very careful observations, that the epidermis consists of two 

 layers, and that it is only the upper layer which is porous, 

 wherever the pattern is white. These white or porous portions 

 of the epidermis differ from the other parts of the upper layer 

 only in having been deprived of, or in never having possessed, 

 the element which gives transparency to the membrane ; in the 

 same manner as hydrophanous opal has become white, from the 

 expulsion of its water of crystallization." 



There is little variety in the animal of Bulimus : the Chilian 

 species are mostly of a light colour, and a few in this and the 

 Columbian district are spotted, some having a transparent shell 

 through which the spots are visible. The Philippine species are, 

 without exception, of a sombre olivaceous brown, and dwell in 

 family groups, as it were, among the shady foliage of the branches. 

 Out of a group of some dozen living specimens, not more than 

 three or four may be found in an adult state with the lip of the 

 shell reflected. They may be dislodged by shaking the branches, 

 but are chiefly disturbed by the heavy rains with which these 

 islands are at times visited. Mr. Cuming preferred, however, to 

 collect them in dry sunny weather, because he was sure of finding 

 the objects of his search in their shady places of retreat. In the 

 immense sandy tract on the west side of the Andes, the reverse 

 of this condition of nature prevails. The Bulimi are here phy-; 

 sically very distinct ; some reside all the year round upon the 

 numerous Cacti, but during the dry season, which lasts for several 

 months, they live mostly in a state of torpor, inclosed within 

 their shell by an epiphragm, and buried in the sand or under 

 stones. On the approach of the dews they revive to a state of 

 animation, and crawl about at night in quest of food. 



In illustration of the remarkable drought that prevails in 

 Northern Chili, and of its effect upon molluscous life, I am 

 tempted to repeat, in brief, an anecdote related to me by Mr. Cu- 

 ming. On the arrival of our friend at the port of Copiapo in 1829, 

 he discovered the beautiful Bulimus Broderipii in considerable 

 numbers, in the fissures of the rocks that may be seen here and 

 there in the sandy plains of that country. Finding a large pro- 

 portion of them dead, with the soft parts entirely decomposed, 

 he requested a solitaiy inhabitant of the place to collect as many 

 specimens as he could pick out alive, whilst he occupied himself 

 in botanizing. Returning from his excursion, Mr. Cuming was 

 greatly disappointed to find that among the quantity his Chilian 

 collector had accumulated, there was scarcely one in a living state. 

 Upon remonstrating wath him for his inattention, the native re- 



