Biofilm Guide 5 Kindgom Animalia Phylum Arthropoda -­‐ meaning jointed legs, this phylum includes organisms like spiders, crabs, centipedes, millipedes, and insects. 1 cm 1 cm Mud Crab: mud crabs make their home on the biofilm substrate and prey on the organisms that attach to the disc. Amphipod: amphipods are shrimp-­‐like organisms that feed on algae and detritus. Amphipods resemble their land dwelling relative the sow bug.