PorpitaPor"pi*ta\, n. [NL., from Gr. ? brooch.] (Zo["o]l.) A genus of bright-colored Siphonophora found floating in the warmer parts of the ocean. The individuals are round and disk-shaped, with a large zooid in the center of the under side, surrounded by smaller nutritive and reproductive zooids, and by slender dactylozooids near the margin. The disk contains a central float, or pneumatocyst.