"They are all going to unmask at half-past ten." So the unrecognized intruders slipped away, stationing themselves about the room.
Pretty soon a rumor began to spread among the dancers that there were young men present.

No one knew exactly how it started, but it grew and spread with such persistency that it finally reached the ears of the chaperon.
"Some of the girls saw their feet," said her informant, "and not only their feet but their trousers, too." The teacher rose and rapped sharply for order.
"Young ladies," she called in a loud voice, "I am sorry to disturb the dancers, but we have every reason to believe there are some men in the room.

Since it is not yet time for you to unmask, it will be simple to find out who does not belong here by having you file past me.

I will lift each mask myself." The dancers accordingly arranged themselves in a long line and walked single file past the teacher.

She saw only girl's faces, however, as she peeped under the masks, and the dance proceeded.
The next disturbance came when the maskers had all taken their stand at one end of the room at the request of the six dominoes, who managed to whisper to each sophomore that there was presently to be a surprise.
An expectant hush fell over the company as the six dominoes filed out of a side room and stood, for a moment, in full view of the sophomores.
Then the six deliberately lifted their dominoes, disclosing trouser legs and men's shoes.