“And in four hundred years Kino’s people had learned only one defence- a slight slitting of the eyes and a slight tightening of the lips and a retirement.”

I'm not sure what you want to know about this quote, but it is used to describe Kino's people and the way they've been forced to be contented with their lot. The men Kino sees to sell the pearl all know they can get it for next to nothing is they all give him low bids; Kino's own social class knows this as well...... and all they can do about it is get angry (thus the facial expressions) and stay silent.