Ooops Pronouns please
That must be It Crab Soup
How to Tell Female From Male Crabs
"If you are catching your own crabs to use for she-crab soup or other dishes, you will need to be able to tell females from males. Luckily, this is easy to do, and you will not need a magnifying glass. Simply look at the underside of the crab. For example, the female blue crab, which is typical for East Coast crabs, has a broad, triangular-shaped area in the center of the shell, whereas the male has a more distinctive, elongated spire in the center."
Leave it to lefties to make that more complicated than it really is.
Either a broad triangular area or elongated spire.