"Bone?" Identification please

A friend, Robert Shearer, found this "bone?" Scuba diving the other day.

It was found in the sand in 72' of water at

Hog Heaven Reef off Boca Raton, FL, on 6/5/2010

It looked like bone to Robert.

Can anyone help identify what it is and what it is from?

Thank you Anne

That's actually an easy one Anne. It's one of the bones underlying the plastron, the ventral surface of a turtle's shell. What I don't know is what kind of turtle.....

http://www.jaxshells.org/919za.htm

http://chestofbooks.com/animals/Manual-Of-...I-Chelonia.html

Thank you so much Leslie. The links are wonderful. And I should have known you would be working on a Saturday! Anne