Invertebrates are all animals that do not have a backbone.
Mollusks like clams and octopi
They have a shell or a mantel
Arthropods like spiders and crabs
They have an exoskeleton, segmented bodies & jointed appendages.
Annelids & Platyhelminthes like worms
They are segmented with soft, bilaterally symmetrical bodies.
Echinoderms like starfish
They have a five part radial symmetry, internal skeleton and water vascular systems.