What is the name of the percussion instrument...

[David O]

...like a tambourine but semicircular and without a skin?

[cconsaul]

That is also a tambourine, although it is also called a rock tambourine. It is semicircular with an indented hand-hold so that the instrument can be played for long periods of time without (as much) fatigue. It can also be hit against another object such as a person's leg or a cowbell,for a variety of effects. Hope this helps.

www.lpmusic.com (http://www.lpmusic.com/Product_Showcase/Tambourines/index.htmlhttp://en.wikipedia.org/wiki/Tambourine)