NEMATODE PARASITES OF BIRDS 



377 



Female 27 10 40 mm. long by 350 to 500/* wide. The vulva is at 

 the posterior end, just anterior to the anus (fig. 437). Eggs 85 to 

 88/* long by 36 to 40/* wide, oblong, somewhat truncated at the ex- 

 tremities, covered with slightly salient granules or tubercles, com- 

 paratively large and thickly set. 



Life history. — Unknown. Apparently the worms undergo at least 

 part of their molts in the tissues of the host and may die there, leav- 

 ing their borrows filled with eggs as the worms themselves decom- 

 pose or are absorbed. This habit is somewhat similar to that of 

 Hepaticola hepatica, a hairworm in the liver of rats and not a re- 

 mote relative of Hystrichis. There are probably intermediate larval 

 stages in fish, according to Jaegerskiold. 



Distribution. — Europe (France, Germany, Italy, Hungary and 

 Ireland). 



Fig. 437. — Hystrichis tricolor. Head and tail ends of female. After 



Jaegerskiold, 1909 



HYSTRICHIS ACANTHOCEPIIALICUS Molin, 18Gla 



Synonym. — Strongylus tubifex tantali. 11 



Hosts. — Primary : Ibis nudifrons, Phimosus infuscatus; second- 

 ary : Probably fish, according to Jaegerskiold. Ibis tubifex, re- 

 ported as a host in the index-catalogue of Stiles and Hassall, is a 

 lapsus, the generic name of the host (Ibis nudifrom) having been 

 combined with the specific name from the synonym. 



Location. — Glands of proventriculus. 



Morphology. — Hystrichis (p. 375) : Swelling of head end (fig. 

 438 a and b) slight or lacking. Head with 7 to 9 circles of spines, the 

 spines relatively sparce, not closely set, the largest 25 to 30/* long by 

 15 to 17/* wide. Mouth opening triangular; mouth cavity 130/* long. 



Male 23 to 15 mm. long; maximum width 1.5 to 2 mm., width at 

 head end 270 to 200/*, at tail end (just anterior to bursal cup) 1G0/*. 

 Spines on anterior part of body to a distance of 800/i from head end. 

 Esophagus about 8 mm. long. Bursal cup 100/* long by 240/x wide, 

 a round bell-shape, its walls thick, muscular (fig. 438 c and d). 



Female 35 to 47 mm. long; maximum width 2 to 3 mm., width at 

 head end 300 to 3G0/*, at tail end 320 to 350/*. Spines on anterior part 



11 Catalogue of the Vienna Museum. 



