ammotelic--ammonia
uricotelic--uric acid
ureotelic=urea

Malphiggian tubules
crustacean-green  gland

Nervous system

cellular level
cell membrane polarity
decremental
porifera
cnidaria
nerve  net
platyhelminthes
subepidermal nerve net
ladder type nervous system
pair of parallel nerve tracts
ganglion and a nerve