NEMATODA 



223 



N. americanus* (Stiles). American hookworm (Fig. 355). Male 9 

 mm. long; female 11 mm. long; vulva in forward half of body; eggs 

 (Fig. 345, B) about .07 mm. long by .038 mm. broad: in the small intes- 

 tine of man and the gorilla, where it moves about sucking blood, causing 



Fig. 355 — Necator americanus. A, dorsal view of head, showing cutting lips and teeth 



(Looss) ; B, hinder end of male, showing bursa (Stiles). 



1, ventral cutting lips. 



often a severe SBnemia; very common in the South among the poorer 

 classes; the eggs pass out with the feces, the young worms living in the 

 moist earth; infection may be got by drinking infected water, by eating 

 infected substances, and even as the result of the migration of the young 

 worms through the skin of feet or hands. 



5. Anchylostoma Dubini. Similar to Neca- 

 tor but with head end not narrower than body 

 and with 2 pairs of large ventral-curved teeth 

 and a pair of dorsal teeth in place of the cutting 

 plates, directed forwards ; vulva in hinder half of 

 body: 5 species. 



A. duodenale Dub. (Figs 345, A, and 356). 

 Old World hookworm. Length of male 9 mm.; 

 of female 12 mm.: in man, in Europe and Asia, 

 occasionally in America. 



A. caninum (Ercolani). Similar to^he above 

 but somewhat larger: common in dogs and eats and often fatal to young 

 animals. 



6. Strongylus 0. F. Miiller. Similar to Anchylostoma but with 

 two long glands opening into the mouth, around which are small flat 

 spines: numerous species. 



* See "Report upon the Prevalence and Geographic Distribution of the Hook- 

 worm Disease in the United States," by C. W. Stiles, Bull. No. 10, Hygienic Lab., 

 Treas. Dept., 1903. "Uncinariasis in the South," by C. A. Smith, The Jour, of the 

 Am. Med. Asso., Vol. 41, p. 709, 1903. "The Anatomy and Life History," etc., by A. 

 Looss, Records of School of Med., Cairo, 1911. 



Fig. 356 

 Anchylostoma duodenale 

 — dorsal view of head, 

 showing teeth (Looss). 

 1, ventral teeth. 



