PRINCETON, N. J., May 23.- The lacrosse championship was decided today by Princeton defeating Harvard by 2 to 1. Both teams had won every previous game they had played in this year's championship series, and thus to-day's game was most important. The playing on both sides was very fine, Harvard doing the better team play and Princeton the more brilliant individual work. The goals for Princeton were thrown by Bonsal and Paxton. The playing of Harvey, of Harvard, and Poe, of Princeton, merit special praise. The victory was unexpected by Princeton, whose team has been much broken up by sickness and loss of members.