Mermaid

That's Belita doing an underwater royal flash.   From another hokey Life photo essay in the August 27, 1945 edition.

See the story at:

https://books.google.com/books?id=e0gEAAAAMBAJ&pg=PA15&dq=cancan&hl=en&sa=X&ved=0CDQQ6AEwBjgeahUKEwjao4SU6IjGAhVDCpIKHTNSABs#v=onepage&q=cancan&f=false

For a nice filmed cancan showing a dried-off Belita, see:

http://classiccancan.blogspot.com/2013/06/belita.html

Belita

A great old television performance of the cancan by Belita (Gladys Lyne Jepson-Turner) a British skater, actress, swimmer and ballet dancer.  You can see the balletic approach in her performance.

This is from a You Tube video posted by swan2612:

http://www.youtube.com/watch?v=HRRwhWea_mI

More about Belita:

http://www.filmnoirfoundation.org/belita.pdf

http://en.wikipedia.org/wiki/Belita

http://www.proskatinghistoricalfoundation.org/belita.html