OOHRAH!
I must say that the uniforms look much better these days! 🙂 and this picture looks like it maybe an early re-enlistment oath in the early 1920s based of the fact that the females depicted consist of at least 2 Corporals and 3 have already been awarded the national defense ribbon meaning they had already served at least 30 days or more during a time of war not to include training.
The first female to enlist in the Corps was Opha Mae Johnson in August of 1918, whom was the first of 305 women to enlist that day. Most of those who enlisted became either secretaries or cooks rather than the stereotypically represented billet of nurses during WWI. To this day, all of the Marine Corps medical attention is essentially provided by Navy Corpsmen.
Additionally, female training has come along since then back in the 1920s, Boot camp consisted of learning how to properly apply their make up and the upkeep of their uniform, rather than the physically demanding training that female recruits receive today.
Just a little bit of Female Marine History for ya!