"- We'll see you again, Haines said, turning as Stephen walked up the path, and smiling at wild Irish.
Horn of a bull, hoof of a horse, smile of a Saxon.
- The Ship, Buck Mulligan cried. Half twelve.
- Good, Stephen said." (U1.730)
A variant on 'Three things to be distrusted: a cow's horn, a dog's tooth, and a horse's hoof' heard by Dr. P. W. Joyce in his youth among the people of Limerick. It is an example of an 'Irish triad', a common Irish device of grouping items in threes that dates back to the 9c. [suggested by Michael Reidy, a visitor to the site]