Date of this Version
Journal of Parasitology (September 1916) 3(1): 21-27.
Also appeared as Contributions from the Zoological Laboratory of the University of Illinois, number 72, under the direction of Henry Baldwin Ward.
Extended study of North American representatives of the three trematode families, Polystomidae, Aspidogastridae, and Paramphistomidae has made possible the first comprehensive treatment in this country of their structure and classification. Four new species are added to the genus Polystoma and three new species of two new genera are added to the Paramphistomidae.