ID this hitchhiker

[kysalty]

I found this









on my purchase from today



The shell-like part is somewhat flat and hard.n There were two of them, this was the biggest one. Any idea of what they are? Good or Bad?

 

[iamwhatiam52]

Looks like a Stomatella, but I have never seen one so round.

Good guy.

 

[dalston]

It's a stomatella sp. A harmless grazer, good guy to have.

 

[kysalty]

Thanks for the info everyone. I will be adding these guys to my display.