Prosthiostomum cf. trilineatum

This little flatworm was found inside a dead Black-lipped Pearl Oyster shell.  While examining the bryozoan, algae, sponge and ascidians within, I noticed the worm make an appearance and quickly move to the outside of the shell.  This particular animal was approximately 40 mm (they can reach 60 mm or over 2 inches).  It stretched out and moved quickly amongst the algae until in disappeared into a crevice in the shell.  In a couple of the photos you can see the distinct eye-patch in between the area where the two orange medial lines end and the very obvious tranverse orange and black line begins.  At first I thought I was seeing another  Cestaplana rubrocincta but that animal is much more ribbon-like and lacks the two distinct converging medial orange lines.  For more information and photos see John Hoover’s Flatworm page.

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