Annelids: Segmented Worms
Repeated segmentation, internally separated by septa
Cephalization: anterior segment differentiated as head - sensory organs (eyes), cerebral ganglion (simple brain) controls nervous system and hormonal system
Connections run through septae and connect whole body:
- intenstine
- ventral nerve cord (with ganglion in each segment)
- closed blood system with dorsal and ventral vessel; first 5 lateral vessels (each side) enlarged and muscular: serve as hearts
Nephridia: similar to mollusks, two per segment