Two new species of Kalyptorhynchia (Plathelminthes) from the N American Atlantic coast

The kalyptorhynchs (Platyhelminthes, Rhabdocoela) Gnathorhynchus riseri sp.n. (Gnathorhynchidae) and Placorhynchus doei sp.n. (Placorhynchidae) are described from coarse sandy shores in Massachusetts, U.S.A.. G. riseri and its probable sister species G. rostellatus Brunet, 1973 have similar copulatory bulbs with prostatic fascicles enclosing the ejaculatory duct, in the former species differentiated to an eversible penis papilla. P. doei is identified by its pointed sclerotic copulatory stylet, dissolved by acid fixatives.