Estrella Mountain Community College
Estrella Mountain Community College: Phylum Annelida
This section (in table of contents as "Phylum Annelida: Segmented Worms") gives a description of how segmented worms developed certain characteristics as well as it explains the differences in the evolution of different classes of...
Regents of the University of Michigan
Animal Diversity Web: Class Polychaeta
Resource provides a general description of marine worms, including sand worms, tube worms and clam worms.