Protostomes that have a closed circulatory system and true segmentation. Protostomes that have an open circulatory system and a trochophore larva. 3 embryonic germ layers. You are given a bilaterally symmetrical worm-like animal to identify. Upon dissection you find that an endoderm, mesoderm, ectoderm, and true coelom are present.
Some members have a cartilaginous endoskeleton.
Includes salamanders, frogs and toads. Includes snakes, turtles, and lizards. Some items may be used more than once or not at all. Arthropoda Part III-Short Answer. This phylum is internally segmented as annelids but its jaws are derived from appendages as arthropods.