The way the shoulders are held together reminds me of a Greek chiton! I love the entire Grecian feel to this! Note the repetition of the Greek key on the bonnet, trim, and even the cuffs of the pantaloons! Even the sandals are Grecian!
The Greek Keys were used quite often in fashion as seen on this 1862 gown from the Met.
The Victorian Archive
Bathing Costume with Caps and Bathing Slippers