Complex sentence: At Yale, Crossman was on the Freshman Football Squad, the "Yale Daily News" Board, and the Senior Class Book Committee; additionally, he was a member of Psi Upsilon and Wolf's Head Society.
Split into simpler sentences: At Yale, Crossman was on the Freshman Football Squad, the "Yale Daily News" Board, and the Senior Class Book Committee. Additionally, he was a member of Psi Upsilon and Wolf's Head Society.