NO. 2131. NEMATODE PARASITES OF RODENTS— HALL. 153 



HELIGMOSOMUM GRACILE (F. S. Leuckart, 1842) Railliet and Henry, 1909a. 



/Synonyms. — Strongylus gracilis F. S. Leuckart, 1842; Meta- 

 strongylus gracilis (F. S. Leuckart, 1812) Molin, 1861«; Strongylus 

 myoxi Rudolphi, 1819, of Diesing, 1851, and Stossich, 1899. 



Specif c diagnosis. — IleJigmosomum (p. 119) : Body ^\'hitish brown, 

 thinning anteriorly. Head small, elongate, and obtuse. Mouth- 

 simple and orbicular. Two large cervical alae present. 



Male 6 to 7 mm. long. Large campanulate bursa, slightly incised 

 on the dorsal border, and with small rays. Spicules long and 

 filiform. 



Female 9 mm. long. Body thickens posteriorly and terminates in 

 a conical mucronate point. 



Host. — Glis glis {Myoxus glis). 



Location. — Intestine. 



Localities. — Germany (Freiburg), Austria (Trieste), Italy (Pisa). 



This worm was originally described under the specific name used 

 here by Leuckart. Dujardin has quoted Leuckart's description with 

 the comment that it is very probably identical with some one of the 

 species made by him (Dujardin), i. e., one of the species now trans- 

 ferred to the genera HeligmosomuTn and Viannaia as II. costellatum, 

 H. laeve, II. minutum, and V. 'polygyra. At the same time Dujardin 

 did not go farther in attempting to identify Leuckart's species wath 

 any one of these, and there seems to be nothing to be gained by sup- 

 pressing what may prove to be a good species on the strength of a 

 casual opinion. Strongylus myoxi Eudolphi, 1819, has never been 

 described and must be regarded as a nomen nudum, since there are 

 at least two species of Ileligmosomwn, II. gracile and II. laeve, 

 described from species formerly referred to the genus Myoxus. 

 Stossich (1899), however, regards Strongylus gracilis and Meta- 

 strongylus gracilis as synonyms of Strongylus myoxi, but does not 

 discuss the point. 



HELIGMOSOMUM LAEVE (Dujardin, 1845) Railliet and Henry, 1909a. 



Synonyms. — Strongylus laevis Dujardin, 1845; Metastrongylus 

 laevis (Dujardin, 1845) Molin, 1861«/ Strongylus poly gyrus Du- 

 jardin, 1845, of Stossich, 1899. 



Speci-jic diagnosis. — Ileligmosomum (p. 149) : Body filiform, red- 

 dish, slightly attenuate anteriorly, more or less enrolled, but not in 

 a permanent manner. Cuticle slightly striate transversely at inter- 

 vals of less than 2 /x. Two lateral lines or crests are visible at times. 

 Head thinned, obtuse, 38 fi in diameter, exclusive of the surrounding 

 vesicular cuticle, and 60 ]}. in diameter, inclusive of the vesicular 

 cuticle. 



