Diniatys dubius can sometimes be found in large numbers in the Marshalls on shallow lagoon reefs in Lyngbya encrusted Halimeda patches and on sandy slopes at depths of 6-30m. This is also figured in Sea Slugs of Hawaii. As shown in the photos on the Hawaii site, many will attach their bubble-like egg masses to the Halimeda plants all at once.
Usually quite common, on 24 April 2011 they seemed even more abundant in some lagoon algae patches, many producing egg bubbles like the one below.
I like all the little tiny forams mixed into the algae and sand around the two specimens below.
Another one with a bubble egg mass.
Created 4 November 2007
Updated 13 April 2014