The undefeated Crimson mermen will work out in the Indoor Athletic Building pool this evening at 8:15 o'clock with the Boston Y.M.C.A. providing the opposition. For the Ulenmen, the engagement will be nothing more than a tune up for the League encounter with Columbia on Saturday.

Free-styler Bill Runge is probably the only visitor who has a good chance to figure in the scoring, save for the customary thirds which any losing side must take. Runge is a sprinter, capable of pushing Jim Curwen, Lonnie Stowell, and Dave Stearns, but the Crimson trio should beat him.

Art Bosworth may not see much action in the backstroke tonight, thus giving McHugh and Tirrell of the Y. M. C. A. a chance in the dorsal event. Breastroker Hayward has only been beaten once this year, and his Harvard opposition will come from among Al Waldron, Max Kraus, Roger Wilcox, and Bob White.

Last year the Crimson tankmen downed Boston 59 to 16; the year before it was 62 to 13. Coach Ulen can win as he pleases tonight and will probably want to let some of his inexperienced men see action.