Botrylloides sp.

Scientific name : Botrylloides sp.

Encrusting colonial ascidian, with many small

zooids disposed in chain around a common cloacal siphon. Brown colour, with black and white lines on zooids.
Amongst ascidians, some similarity exist with encrusting didemnids. In didemnids the oral siphons are small and uniformly distributed among the larger cloacal siphons. In Botrylloides oral siphons are disposed in chains, in systems with more than 20 zooids each.
The similar genus Botryllus have zoids in chains shorter than 20 zoids.
At a first glance, confusion is possible with an encrusting sponge: putting a hand close, gently, if siphons close this must be an ascidian (sponges can not close their pores).