Explanation !!

A woman came up behind her husband while he was enjoying his morning coffee and slapped him on the back of the head.
"I found a piece of paper in your pants pocket with the name `Marylou` written on it," she said, furious. "You had better have an explanation."
"Calm down, honey," the man replied. "Remember last week when I was at the dog track? That was the name of the dog I bet on. "
The next morning, his wife snuck up on him and smacked him again. "What was that for?" he complained.
"Your dog called last night."