questionable

I got a female pit about a year ago. They claimed she was a reverse blue, she has a very odd personality, there are people she don't like, and people she loves. We also have a male Boston Terrier, they play fight all the time. The other day Missy (the pit) some how got her tooth in the Bostons...

Does anyone know what kind of meat/part of animal this is? I have an idea but need a second opinion. My grandmother went to the butcher and picked up some cheap meat from the butcher and a few of these were in the bag along with various other pieces of flesh.