>Once I got a beautiful big landshell species from you, large ... maybe a
>couple of inches ... and brown and extremely glossy and impressive.  I laid
>it on a shelf where I was displaying some other landshell species (I may
>admire the critters, but don't pretend to know much about them, and am still
>somewhere in the curiosity stage of collecting them). It lived happily there
>for quite some time, and then one day I found it broken to bits.  Some
>pieces were on the floor and some were scattered about on the shelf.  I
>blamed my cats, never completely trustworthy where interesting smells might
>linger, or my sons, who had never quite accepted the concept that bouncing
>balls in the house would get them into trouble every time. Neither cats nor
>kids fessed up. And I nursed a grudge over my lost shell until I happened to
>mention it to you later and you told me the species was notorious for being
>a time bomb...something to do with drying out.  Can you refresh me on this?
>(Yes, I apologized to both cats and kids.  The kids were churlish about it,
>and added it to an ever-growing list of stuff they unjustly were blamed for.
>They think there's a book in it.)
 
Perhaps it was a Paryphanta. They're large, and blow up like grenades.
 
As an aside, many freshwater mussels do the same. It has to do with the fact
that the periostracum and the shell expand and contract at different rates
as they dry, or even react to changing temperatures. The periostracum
shrinks more than the shell. In thin-shelled species, the periostracum wins
and the shells crack (I can hear them "popping" in the collection range when
the AC is on). In thick-shelled species the shell wins and the periostracum
pulls itself apart and eventually flakes off.
 
*  G Thomas Watters               *
*  Ohio Biological Survey &       *
*  Aquatic Ecology Laboratory     *
*  Ohio State University          *
*  1315 Kinnear Rd.               *
*  Columbus, OH 43212 USA         *
*  v:614-292-6170 f:614-292-0181  *
 
"The world is my oyster, except for months with an "R" in them" - Firesign
Theater