[Rondo]

maybe temple block? in shape of mouth.
cajkovski wrote a kinder trommel

Temple block is right. Claves sound similar, with a kind of *snap, snap* sound.

They are used in Grofe's Grand Canyon Suite in On the Trail, as well as Sleigh Ride, and various soundtracks of spaghetti westerns.

 

[Rondo]

I particularly enjoy Bartok's compositions with percussion instruments. Beethoven also did some pretty good percussion writing in his later works.