NO. 2131. 



NEMATODE PARA.'^ITES OF RODENTS— HALL. 



161 



^____-.^ 



Type-species. — HeligmosoTnoides linstoun Hall, 191G. 

 I am not sure that my interpretation of von Linstow's figures of 

 the bursa is correct. The figures present some peculiarities. 



HELIGMOSOMOIDES LINSTOWI Kali, 1916, new name. 



Synonym. — Strongylus poly gyrus Dujardin, 1815, of von Lin- 

 stow, 18785 and 1879«. 



Specific diagnosis. — Ileligmosonioides (p. 160) : Worm, reddish, 

 spirally coiled. Mouth aperture triangular with four circumoral 

 papillae. Cuticle dilated about head and Avith 16 longitudinal stria- 

 tions, in part wavy, along 

 body. Transverse stria- 

 tions present and spaced at 

 about the same interval as 

 the longitudinal. 



M(de 4 mm. long and 78 /x 

 thick. The bursa structure 

 is that given in the generic 

 diagnosis. The spicules are 

 540 /A long. 



Female 7.2 mm. long and 

 96 II thick. The anus is 98 

 ^ from the tip of the tail, 

 the tail ending in a fine 

 terminal point 16 \h long. 

 The vulva is anterior, 210 

 ju, from the anterior end. 

 The vagina is 720 jw long 

 and is directed posteriorly 

 (presumably). It joins an 

 ovijector 180 /* long (fig. 

 207). At the anterior end 

 of this is a spherical body. 



Fig. 207.— Heligjiosomoides 

 UNSTOWi. Vagina and 

 ovijECTOK. Enlarged. 

 After von Linstow, 1882. 



Tig. 208.— Heugmoso- 

 moides linstowi. 

 Embryo. Enlarged. 

 After von Linstow, 

 1882. 



Anterior of the latter is a muscular uterus 180 /x long and anterior 

 of this is the ovary. The eggs are 75 by 43 /^ in diameter. 



Life klstory.—in eggs placed in moist earth embryos (fig. 208) 

 develop in eight days. The embryo is 310 /x long and 23 fi thick. 

 The mouth has two conical projections and the tail is awl-shaped. 

 The esophagus is 1/2.4 and the tail 1/4.7 of the total body length. 



Host. — Microtus arvalis (Arvicola campestris). 



Location.— IntestinQ, partly in saclike depressions apparently 

 caused by the worm. 



Locality. — Germany. 



10600°— Proc.N.M.vol.50— 16 11 



