Final answer:
Colonial sea squirts, like salps, have individual siphons per member of the colony used for feeding on phytoplankton and excretion. They exhibit a unique form of coloniality, where individuals are interconnected and capable of budding, akin to the zooids of a siphonophore.
Step-by-step explanation:
In colonial sea squirts, such as salps, each individual within the colony does indeed have its own siphons to facilitate feeding and excretion. Salps propel themselves while feeding on phytoplankton, drawing in seawater through the incurrent siphon where food particles are filtered out by a mucous net. The water and waste are then expelled through the excurrent siphon. These colonial tunicates are known for their ability to reproduce by budding, a form of asexual reproduction where new individuals form directly from the body of the parent organism. Within these colonies, individuals are connected and work together for the survival of the entire colony, similar to the interconnected zooids found in siphonophore colonies like the Portuguese man o' war.