Nervous system had ganglia, and ventral nerve cord with ganglia, with hearing, touch on antennae and chemoreceptors on antennae. Insects and crustaceans have compound eyes of ommatidia that detect movement well. Some have book lungs. Heart pumps hemolymph into arteries Flows into spaces of hemocoel to bathe tissues directly. Ostia are holes in heart wall that let blood in Small coelom around some organs.
Segmentation allows specialization of body regions.
Human muscles and nerves have segmented arrangement. Biramous appendages - appendages with 2 jointed branches from base. Trilobites and crustaceans Uniramous appendages are unbranched. Most biologists think monophyletic, have common ancestor with annelids. Similar embryo segments, nervous systems.