What type of appendages do sponges cnidarians roundworms annelids mollusks arthropods echinoderms and vertebrate have? jointed, not jointed, absent  

Sponges  absent

Cnidarians not jointed  (Aquatic organisms, all have tentacles with nematocysts - stinging cells, used to capture food.)

Roundworms  absent (AKA nematodes are unsegmented, colorless and do not have appendages).

Annelids   not jointed (With the exception of leeches, all annelids have chitonous hair-like structures projecting from their cuticle. These appendages fulfill different functions in different species.)

Mollusks not jointed  (Invertebrates that lack hard appendages such as legs or antennae)

Arthropods  jointed (the arthropods are the only invertebrates to have jointed appendages)

Echinoderms  not jointed  (Due to their radial symmetry, all echinoderms have appendages which point outward from the center of the body like the spokes on a wheel.)

and vertebrate jointed

youre right there are