This pseudocoelomate ["pseudo"-SEE-lum-ayt] phylum includes a model organism studied by Sydney Brenner, called C. elegans.
Parasitic members of this phylum cause river blindness and elephantiasis. This phylum exhibits a radially symmetric head but a bilaterally symmetric body. Trichinosis [trih-kih-NOH-siss] is caused by a member of this phylum whose members are not (*) segmented and have a two-ended digestive system without a stomach. This pseudocoelomate ["pseudo"-SEE-lum-ayt] phylum includes a model organism studied by Sydney Brenner, called C. elegans. For 10 points, name this phylum that includes roundworms.
Parasitic members of this phylum cause river blindness and elephantiasis.
Nematoda (accept nematodes; accept roundworms before mention; prompt on worms)