In this closeup view , the two siphons can be seen opening on the tunicate's upper surface. Several of the fouling organisms are also visible, such as the entoprocts seen above the siphon on the left.
Chelyosoma productum from 75 m depth, San Juan Channel. Width of upper flattened disk on which the two apertures are located is 2.5 cm. This large individual has numerous diatoms and other fouling organisms attached to the tunic. (Photo by: Dave Cowles, July 2008 )