Note: Do not rely on this information. It is very old.
Salpa, one of the best-known genera of the Ascidians belonging to the order Thaliacea. It includes some free-swimming forms of interest, as they exhibit the phenomena of alternation of generations. There is an asexual generation or nurse consisting of a long stolon, upon which buds are developed; these are ultimately set free in a chain and developed into sexual forms; the chain is then broken up into single Salps.