The Rook and the Nozzle

Okay, I'll admit it, that has to be one of the strangest blog post titles!  Are you curious about it?

It probably reveals too much about me.  Or maybe not.  In this case, it shows that I use analogies to learn about and remember things, which can be useful when exploring natural history topics.  (It also exposes my fondness for board games — I'm a poor chess player, but challenge me to a backgammon game and I'll do my best to make it interesting!)

Here's the Rook:

 

And here's the Nozzle:

 

Do you have a guess about what type of animal this is?  Here are the two parts as they appear together:

 

These are the siphons of a small clam.  The "rook" is the inhalant siphon and the "nozzle" is the exhalant siphon.  Clams often have frills surrounding their inhalant siphons to prevent entry of larger particles.  

The exhalant siphon has a thin membrane that appears to function like the nozzle on a garden hose.  This is helpful for jettisoning already filtered water further away from the animal so that it isn't sucked in again by the adjacent inhalant siphon.  (You probably have an intuitive sense for the physics involved — reducing the diameter of the end of the hose results in an increase in velocity of the exiting water.  Hmmm...this also reveals that I'm a fan of the occasional garden hose water fight!)

Here's a view of most of the clam with the siphons extended far beyond the shell:

 

And one of the clam out of the water so you can see the entire shell (which was ~15 mm long):

 

You've probably noticed that I've avoided identifying this clam.  That's because I'm not 100% certain of its identity.  It might be Hiatella arctica.  But if you have thoughts about the species identification, please let me know.