: 1. A genital pouch
of numerous invertebrates.
2. In certain male nematodes and acanthocephalans, a modified caudal ala or alae, circular or oval, may be divided into two lateral symmetrical or asymmetrical lobes, separated by a dorsal lobe, and supported by rays or papillae; bursa.
3. (Arthropoda: Insecta) A female copulatory pouch developed from the tubular vagina in the genital chamber for reception of the male aedeagus. See also genital chamber.
4. (Mollusca) A copulatory pouch or sac for receiving sperm that will be stored for only a brief period; copulatory bursa. See also seminal receptacle.
5. (Platyhelminthes: Turbellaria) In planarians, a blind pouch that holds the secretions from the penis and adenodactyl gland (muscular organ), which then activates the sperm.