Nope the black mask is hidden by the merle, the only reason I say black mask, is his face is blue merle, meaning he has to have a black to start with. Merle is really fascinating. Merle is a dominant gene that is caused by dilution of the "proper" colour, it affects random areas, so that's why you see splotches. Sometimes merle is hidden by certain colours, as those colours aren't affected by merle, like yellow or sable. Which is why you'll see a blue merle with tan markings that have no splotches on them, the merle is only affecting the black part of the coat. Blue merle is actually a black dog, with the dilution causing some areas to appear grey. Both of my little Dachshunds are what's called double merle (or dapple as the colour is called in Dachshunds), meaning both their parents are dapples, and they got a merle gene from each of their parents. Mouse is what's called a "black and tan double dapple" or if she was any other breed she'd be called a "blue double merle" I have no clear idea what Boo is, as his colours are really wonky, but I'm thinking he's a chocolate tweed double dapple. His black is not black, it's a really dark brown, with a true chocolate colour, a light brown and a really light yellow, and his spots are small enough to almost be called flecks. Not normal colours, that's for sure. I honestly dont believe that an ACD x Aussie can be the colour of your gorgeous boy, and black masks do not appear in either breed, but I could be wrong, I am not an expert on those breeds by any means.