We believe that Punky is a Boston/Boxer mix. She has the Boston snout and ears (no Boxer jowls) and it's occasional breathing issues. She has a long tail, ears a bit more rounded and a long, lean body with a broader chest than a Boston but not quite as much as a Boxer. At first, we thought she might be Boston/Jack Russell but others, including my parents, who have had three Boxers, have noted the resemblance to a boxer.
She is six months old and still coming out of her shell peronality-wise since we adopted her a month ago. She also used to be afraid of larger dogs. She's overcome that somewhat but will still show fear if a strange dog approaches her in an aggressive manner.
We have a 4-year-old Rat Terrier. Punky fought with her a few times the first two days but has since learned to get along with her. There are still some times when she wants to play and out Rattie doesn't, but it doesn't get nearly as bad as it used to. Right now, they're both napping at the edge of my bed.