Cyphonautes

A cyphonautes is a larva of an ectoproct or bryozoan. It is triangular in profile with a heavily-ciliated band called the corona at the base of the triangle and a sense organ at the apex (cypho-, bent; nautes, sailor). The beating of coronal cilia propels the cyphonautes through the water and contributes to a feeding current. The cyphonautes is very thin, i.e. laterally compressed, and is bounded laterally by two valves or shell plates. The internal anatomy of the archetypical cyphonautes, such as the one featured in the life cycles of Membranipora, includes a complete digestive tract with a stomach entrance near the apex and a hindgut ending in an anus near one end of the base. At the other end of the triangle's base is the pyriform organ, a heavily ciliated and glandular complex that functions in site selection at settlement.