’Twas the season for these Princeton women to raise their voices in song, but archivists were unable to date the year of their performance or provide their identities. A good bet is that these students were members of one of Princeton’s a cappella groups and that the occasion was one of many arch sings on campus. Once limited to just a few groups, Princeton women today have a multitude of vocal organizations — some coed and some all-female — to which they can lend their voices, from the venerable Tigerlilies (founded in 1971) and Katzenjammers (begun in 1973) to Shere Khan and Koleinu, both begun in the mid-1990s.