664 



NEMA THELMINTHES 



Triehostrongylus Looss, 1905. 



Trichostrongylidse with body tapering gradually from the genital 

 opening anteriorly. Head with three small lips and blunt or 

 pointed papillae, without cuticular protuberances or neck papillae. 

 Cuticle transversely striated; oesophagus long. Male with the 

 bursa closed round by large side-flaps, without evident median 

 folds; spicules spoon-like, with a boat-shaped accessory piece. 

 Female with the genital opening in the posterior half of the body. 

 Tail short, with two small papillae near the tip. Egg thin-shelled. 



Type Species. — -Triehostrongylus retortcBformis Zeder. 



Four species of interest in tropical pathology: Triehostrongylus 

 colubriformis, T. probolurus, T. vitrinus, and T. orientalis. 



Triehostrongylus colubriformis Giles, 1892. 



Synonyms. — -Strongyles colubriformis Giles, 1892; S. instabilis 

 Railliet, 1893; S. subtilis Looss, 1895. 



This species was found by Looss in post-mortems on fellahs in 

 Alexandria and Cairo, and also by Ijima in a woman in Japan. In 

 man, however, it is only an accidental parasite, being usually found 

 in the duodenum, rarely in the stomach, of sheep, antelopes, drome- 

 daries in Egypt, monkeys in North America, and sheep in India. 



Morphology. — Male 4 to 5 millimetres in length, and o-o8 milli- 

 metre in thickness just in front of the bursa. Spicule 135 to 145 ^ 

 in length, and the accessory portion 70 /ll in length, with a long 

 muscular oesophagus. Bursa with two lateral semicircular wings 

 connected by a cross-bridge. Ribs arranged asymmetrically. 

 Female 5 to 6 millimetres in length, and about ()'09 millimetre in 

 breadth. Posterior extremity tapers to a pointed tail, in front of 

 which the anus is situated, 0*055 "to 0-07 millimetre, and the vulva 

 1-05 to I '2 millimetres. Eggs 72 to 80 fj, by 40 to 43 /j,; when 

 oviposited, generally contain eight to twelve celled embryo. 



Life-History. — Resembles that of Ancylostoma duodenale outside 

 the body, according to Leiper. 



Pathogenicity. — •Believed to be unimportant. 



Triehostrongylus orientalis. 



Synonym. — Triehostrongylus subtilis Looss, 1895. 



Triehostrongylus eggs have recently been found in the faeces of 

 a considerable percentage of the agricultural population of certain 

 districts in Japan, and is probably the same as that recorded pre- 

 viously from Japan by Ijima and Looss as Triehostrongylus subtilis 

 {vide T. eolubriformis, supra). This species differs slightly in details 

 of ray-disposition in the bursa and in configuration of the spicules. 



Triehostrongylus probolurus RailHet, 1896. 



Synonym. — Strongylus probolurus Railhet, 1896. 

 This parasite lives in the duodenum of sheep, antelopes, and 

 dromedaries in Egypt, and has also been found in man in Egypt. 



