Molluscs
Gastropods
radula and its uses
grazers have very long digestive tracts because of the
prominence of cellulose in their diets
dog whelks--carnivores (drills)
Cephalopods--
very functional digestive tract
chitons--grazers-show homing behavior
Arthropods
mandibles and chelicera
horseshooe crabs and gnathobases
insects
mandibles, plus other parts
Echinoderms
echinoids--grazers--aristotles lantern symbionts