[From Introduction]
The phylum Annelida, segmented worms, include species from all sorts of environments. Apart from most of the leeches, the annelids have bristles, chaetae, usually arranged so that there are two or four bundles of bristles per segment. The bristles consist usually of bundles of long, slender scleroprotein tubes or rods, glued together by chitin or other forms of scleroprotein.
