Bubbles . . . ?

Well, I never   . . .  !

Extra is another aama crab displaying a 'sponge' under her abdominal flap. 
Some info here.   Trying to find out more.  See update below.


Update:   Courtesy of Susan Scott:  
Crabs that spend part of their life out of the water, like aama, sometimes blow bubbles.  Crabs have gills near the mouth under their top shell.   When out of the water, the crab sucks in air that passes over the gills and supplies the blood with oxygen.   Since the air is going over moist gills, the released air comes out in bubbles near the crab's mouth.

Female aama carry their eggs (the spongy stuff) under the flap on the underside of the body for about 3 weeks.  When they hatch, the larvae swim into the sea as plankton.