Not by name, but he's pretty clear that Mary looks just like his old lover, because he keeps being thrown off every time she opens her mouth and proves just how different they are -- I think it's in TSG when she corners him in the Professor's office and produces the tooth from her handbag. So "friend of the professor who looks just like" would trigger "the Birch", I'd think, unless he's being deliberately obtuse, which would be very Peter.