maxdemo
Love Presas. I have a pair of them; great animals, very loyal and gentle with kids yet will remove the last 1/3 of the arm of anyone acting in a threatening manner towards me or my family. Fun to play with ... wear gloves if you play tug-o-war because you will get rope burn when they decide to stop letting you win.
As for your other, I agree with max1234 -- definately a terrier, maybe Staffordshire or pitbull, mixed in with something else.
Phaedrus