Please help identify large shell

[portlanderik]

This shell is about 20 inches (51cm) long. What is it?
<img src="http://www.home.comcast.net/%7Ehappycollecting123/seashell/shell1.JPG" alt="http://www.home.comcast.net/%7Ehappycollecting123/seashell/shell1.JPG" style="border:0" />
<img src="http://www.home.comcast.net/%7Ehappycollecting123/seashell/shell2.JPG" alt="http://www.home.comcast.net/%7Ehappycollecting123/seashell/shell2.JPG" style="border:0" />
<img src="http://www.home.comcast.net/%7Ehappycollecting123/seashell/shell3.JPG" alt="http://www.home.comcast.net/%7Ehappycollecting123/seashell/shell3.JPG" style="border:0" />
<img src="http://www.home.comcast.net/%7Ehappycollecting123/seashell/shell4.JPG" alt="http://www.home.comcast.net/%7Ehappycollecting123/seashell/shell4.JPG" style="border:0" />

[dave r]

Syrinx aruana, known as the Australian Trumpet shell. It is the largest species of Gastropod (snail) in the world, oh, and they get bigger than yours. I think the record is over two feet!
Dave

[portlanderik]

Thank you Shell-master!