Is this your animal?

http://www.molluscan.com/tripreports/thailand_2_2003/10022003/market03.jpg

I agree with Alan about contacting Marion Havlik and Kevin Cummings.  My
brother found some empty shells in a reservoir formed by damming Raccoon
Creek, I believe.  Those ridges are very prominent and regular.  We have
thundering herds here in Washington state, particularly around boat
launches.

-----Original Message-----
From: Bob Dayle [mailto:[log in to unmask]]
Sent: Sunday, October 09, 2005 2:49 PM
To: [log in to unmask]
Subject: Freshwater clam question...

I was wading in the local creek (central Indiana) when I noted a single
valve in the foot-deep water. Hoping to stir up its mate, I came up,
instead, with a live clam. At a mere 3/4-inch across, it was rather
small,... to someone who has seen three foot wide Tridachna gigas in situ.

Since it is illegal in this state to disturb or molest ANY mollusk, I tossed
it back after noting that the valves were dark brown at the hinge but
quickly gave way to an algae-green color other the rest of the shell. I
estimated about 15 "growth rings" on it.

The questions are two: 1.) Does anyone care to guess what variety of
plecypod this is?, and 2.) What time interval is associated with the growth
marks,...
annual, lunar, sesquiquadrate aspects to the synodic period of Venus,.. or
what?!

Bob Dayle

----------------------------------------------------------------------
[log in to unmask] - a forum for informal discussions on molluscs To
leave this list, click on the following web link:
http://listserv.uga.edu/cgi-bin/wa?SUBED1=conch-l&A=1
Type your email address and name in the appropriate box and click leave the
list.
----------------------------------------------------------------------