57] LIFE HISTORY OF TREMATODES— FAUST 57 



DESCRIPTION OF THE TREMATODES INFECTING MOLLUSKS 



OF THE BITTER ROOT VALLEY 



INTRODUCTION 



On account of the biological isolation of the Bitter Root Valley, it is little 

 wonder that it contributes new species of trematodes. The fourteen species 

 of trematodes found in the valley are not thot to comprise the entire trematode 

 fauna of the region, but are the representative species for the year and season 

 when the study was made. Of the fourteen species found in the Bitter Root 

 River, two are larval Monostomata, two are Holostomata, and the remaining 

 ten are Distomata. In addition to these, a larval holostome, Tetracotyle 

 pip lent is nov. spec, from the vicinity of Chicago, Illinois, is included in the 

 study for the sake of comparison. 



Prevaous to the writers' preliminary report (Faust 1917) the following 

 larval trematodes have been described for North America. 



Monostomata Distomata 



Cercaria hyalocatida Haldemann 1842 Cercaria polyadena Cort 1914 



Glenocercaria lucania Leidy 1877 Cercaria hemilopJmra Cort 1914 



Cercaria iirhancnsis Cort 1914 Cercaria Irigonura Cort 1914 



Amphistomata Cercaria trivolvis Cort 1914 



Cercaria inhabilis Cort 1914 Cercaria rubra Cort 1914 



Cercaria diaslropha Cort 1914 Cercaria douthitti Cort 1914 



Cercaria gorgonocephala Ward 1916 Cercaria wrigbtii Ward 1916 



Distomata Cercaria anchoroides Ward 1916 



Cercaria agilis Leidy 1858 Cercaria marcianae La Rue 1917 



Rhopalocerca tardigrada Leidy 1858 (Really a Distoftmlum) 



Gymnocephala ascoidea Leidy 1877 Cercaria vergrandis La Rue 1917 



Cercaria platyzira Leidy 1890 (Really a Distomidum) 



Cercaria reflexae Cort 1914 Holostomata 



Cercaria megalura Cort 1914 Diplostomidum cuticida (v. Nordmann 1832) 



Cercaria leptacantha Cort 1914 Diplostomulitni grande (Diesing 1850) 



Cercaria caryi Cort 1914 Diplostomidum volvens (v. Nordmann 1832) 



Cercaria isocolylea Cort 1914 Tetracotyle typica (Diesing 1858) 



Cercaria brevicaeca Cort 1914 Dlplostomuliim parvidmn (Stafford 1904) 



Cercariaeiim 

 Cercariaeum helicis (Leidy 1847) Later recorded by Leidy as C. vagans (1850). 

 In addition, there is the doubtful form, Cercaria bilineata Haldemann 1840. 



According to Stiles and Hassall (1908:157), Leidy is credited with the 

 record of a species, Diplostomulum rhachiaeum (Henle). Investigation of the 

 literature shows this to be an error, owing to the confusion of the names 

 Leidy and Leydig. Fr. Leydig described the species D. rhachiaeum for Europe 

 in 1853 (Lej'dig, 1853:383). 



Of the thirty-two forms listed, it is doubtful if any except those described 

 by Cort (1914), Ward (1916) and LaRue (1917) could be recognized by their 

 descriptions, since in the majority of cases the data are so indefinite as to leave 

 the systematist a wide range of choice in determining the species. An excellent 



