ABSTRACT
The Rhabdocoela is a large taxon within the Platyhelminthes, and its members demonstrate a wide variety of forms, characteristics and life styles. Hyman (1951) included the Catenulida and Macrostomida within it (along with the Typhloplanoida and Temnocephalida), while Ehlers (1985a) excluded Catenulida and Macrostomida, but did include the parasitic groups (Neodermata), based on the presumed synapomorphy of a bulbous pharynx. I use Rhabdocoela to include only those species traditionally classified into Kalyptorhynchia, Typhloplanida, Dalyelliida and Temnocephalida, exploring evidence from sperm studies that may be informative about relationships between the principal and subordinate taxa.
