Chordata- Arizona's Tree of Life Web Page. An introduction, pictures, characteristics, phylogenetic relationships and references on chordates.
Introduction to the Chordata- Morphological characteristics of the chordates and also links to additional information.
Phylum Chordata- Animal Diversity Web, University of Michigan. General characteristics of chordates, with links to urochordates and vertebrates.
Phylum Chordata- This site, from the University of Minnesota has information on chordates, and links to some primitive chordates, as well as the vertebrate classes.
