In the Birth of Venus the Goddess Stands in This

This page is the CodyCross answer for the clue below from Brazilian Tour, Group 766, Puzzle 3 (Copacabana Beach).

Question is: In the Birth of Venus the Goddess Stands in This

and the answer is: CLAMSHELL

Word Meaning:

CLAMSHELL — The shell of a clam.

Definitions from Wiktionary.