brood pouch

noun

Sac-like cavity in the parents body in which eggs are deposited and fertilized and larvae develop, such as in seahorses, also: marsupium (the name applied to the brood-pouch in Syngnathidae and Solenostomidae. In Syngnathidae it consists of a vascularized groove formed by flaps of skin along the underside of the tail of males (subcaudal marsupium); in Solenostomidae it is a pouch formed by the pelvic fins, provided with many long filaments, and found only in the female (ventral fin marsupium)).