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ABOUT SHELLS. 621 
norther, which is a drying wind, spring up, and they haste 
away to their retreats with all possible speed. Such a 
shower occurred on a winter night when I was in the neigh- 
borhood of Guane, where there are excellent rocks for shells, 
and many and various shells among the rocks. Early in the 
morning I found some specimens of Melaniella Pichardi. 
They were not abundant, though I saved a considerable 
number, and was desirous of collecting more of them, as 
it is, by no means, common. While I was at breakfast, a 
light norther began blowing. I made but little stay, and 
returned to the rocks, in hopes, though not confident, of 
finding more. Not one was to be seen, however. Similar 
effects are produced by a norther on other shells. Just at 
night I have observed Cyclostoma salebrosum, in numbers, 
on rocks, where, in the morning, if a norther prevailed 
during the night, not one could be found but by searching 
among the leaves at the base of the rocks. This shell, with 
some others, as Cycl. rotundatum-and Cycl. undatum, have 
a way of letting go and rolling to the bottom of the rock if 
it be inclined (and they seem to prefer such), when they see 
the hand approaching; and this, apparently, when they have 
not even one eye open. It would seem as if they felt the 
approach of danger. ee 
_ A group of Cyclostomas, O. claudicans Poey, C. assimile 
Gundl., C. tenebrosum Mor., and perhaps others, spin a 
thread by which they hang from the lower side of projecting 
rocks. When the weather clears after a rain, numbers may 
be found thus at rest, particularly in the early summer, when 
the young abound. Whether they can haul in their line I 
am unable to say, but guess they cannot; for many are 
found with the border broken, which could hardly be so 
common, unless caused by a fall from some height. If in 
this position they fall, it must sometimes be a distance of 
fifty, or, it may be hundreds of feet. These are all thin, 
delicate shells; and the power of suspension seems as if de- 
‘Signed for their injury or destruction. 
