[9] * INSTRUCTIONS FOR COLLECTING MOLLUSKS DALL. 



as that of the log itself, should be closely scrutinized as a favorite 

 retreat of Sycdinia, Pupa, Vertigo, and other small species. With good 

 eyes no hand lens should be necessary, but occasionally a collector will 

 find it of use, and one of the cheap triplets with rubber frames, if care- 

 fully selected, will be found quite as efficient as the expensive achro- 

 matic lenses mounted in German silver which the optician is so prone 

 to recommend. 



LOCALITIES FAVORABLE FOR COLLECTING. 



The margins of brooks and ponds, the under surface of old weather- 

 worn bits of board, leather or bones such as every pasture affords, the 

 earth around rotten stumps and under fallen logs or flat stones, the 

 moist moss near rocks and especially under overhanging ledges, or in 

 marshes, and in general all cool, moist places where decaying, not 

 resinous, vegetation may afford food and shelter for his prey, will be 

 found worth searching by the collector. The fine debris left by freshets 

 along the borders of streams will often yield many small land shells in 

 good condition if carefully searched. In the tropics Morelet has observed 

 that land mollusks are more or less nocturnal. During the day it is 

 necessary to seek them in their retreats under stones, logs, dead leaves, 

 or in the crevices of rocks, unless the atmosphere is moist enough to 

 induce them to remain abroad. During the heat of the day theimbricated 

 leaves of aloes or agaves often hide snails which protect themselves 

 thus from the sun. One may even set traps in the form of fagots, flat 

 stones, pieces of wood or logs, especially in meadows or prairies, where 

 the snails will take refuge during the heated hours of the day. Some 

 mollusks have peculiar habits, as in the case of a little Algerian helix^ 

 which, during the day, buries itself in the loose sand to a depth of several 

 inches, or until it reaches a moist stratum. Some forms, like StropMa 

 in the Antilles, seem to enjoy places where they are exposed to the full 

 glare of the sun. These usually have heavy whitish shells. There are, 

 however, no rules so absolute in such matters as to be without excep- 

 tion. Certain little snails live permanently on the dry, harsh leaves of 

 palms and palmettos or the hispid stalks of tall ferns. In general, what- 

 ever the soil, hilly or mountainous regions are the most prolific in snail 

 life unless too arid, but a certain number seem to prefer the salty moist 

 air of the borders of the sea and these seldom hibernate. The meadows 

 should not be absolutely neglected, especially in the rainy season. 

 Many small Bulimi prefer to reside there and may be found on the 

 stalks of coarse grasses, often in multitudes. Forests are more prolific, 

 especially in clearings and places where the light may penetrate. When 

 the trees stand in marshy places or are subject to overflow, mollusks 

 are less numerous, but multiply where the soil is more or less broken 

 by masses of rock. They are more abundant in broken and irregular 

 woods than when the trees extend uniformly over level ground. In 

 many regions magnificently colored snails live in the tree tops, where 



