from Jim Conrad's Naturalist Newsletter:
selected AQUATIC ANIMALS of the Yucatan

 SHORTCUTS TO IMPORTANT GROUPS OF AQUATIC ANIMALS: 
FISH | MOLLUSKS/ SEASHELLS | BARNACLES | CRABS | POLYCHAETES | VERTEBRATES 
ARTHROPODS:

VERTEBRATES:

MISC. INVERTEBRATES:

IDENTIFY SPONGES at http://www.spongeguide.org by searching an image database on the sponge's color, consistency and morphology