TWO NEW SPECIES OF PARASITIC NEI^IATODES. 



By Brayton Howard Ransom, 



Assistant Custodian, Helminthological CoUections, United States National Museum. 



Since Looss (1905) established the genus Trichostrongylus to in- 

 clude the species T. retortseformis (type), T. instabilis, T. vitrinus, and 

 T. froholurus , several other species have been added from time to 

 time by various authoi-s. Including the two species described in the 

 present paper, the complete list, with hosts and geographic distribu- 

 tion, is as follows: 



T. retortseformis (Zeder, 1800) Looss, 1905; rabbits; Europe. 



T. instabilis (Railliet, 1893) Looss, 1905; man, baboon, ruminants; 

 Africa, Europe, Japan, L^nited States, (?) India. (This and the next 

 following species are perhaps identical.) 



T. coluhriformis (Giles, 1892) Ransom, 1911; sheep; India. 



T. vitrinus Looss, 1905; man, ruminants; Europe, Africa, United 

 States. 



T. probolurus (Railhet, 1896) Looss, 1905; man, ruminants; Africa, 

 Europe, United States. 



T. extenuatus (Railliet, 1898) Ransom, 1907; ruminants; Europe, 

 United States, Australia. 



T. capricola Ransom, 1907; ruminants; United States. 



T. axei (Cobbold, 1879) Railliet and Henry, 1909; horse, ass; 

 Europe. 



T.falculatus Ransom, 191 1 ; goat; Portuguese East Africa. 



T. calcaratus Ransom, 1911; rabbit; United States. 



T. pergracilis (Cobbold, 1873) Shipley, 1908; grouse; Europe. 



T. tenuis (Eberth, 1861) Railliet and Henry, 1909; geese; Europe. 



Strongylus quadriradiatus Stevenson, 1904, and Strongylus nodularis 

 Rudolphi, 1809, which Shipley (1909) has placed in Trichostrongylus, 

 are widely different from the type and should be excluded from this 

 genus. 



Proceedings U. S. National Museum, Vol. 41 , No. 1 864. 



363 



