70 THE HOOKWORMS 



distribution world wide, in tropical and subtropical regions, 

 where there is sufficient moisture for the development of the 

 larval stages. 



Two other species of this genus have been reported from 

 man, Ancylostoma ceylonicun from India and Ancylostoma 

 braziliense from Brazil. Some authorities think that these 

 two forms belong to the same species. They are common 

 parasites of the cat and civet cat and probably only inci- 

 dental in man. 



2. Suit-family Bunostominae. Small buccal capsule, with 

 aperture narrowed anteriorly by plates with cutting edges 

 springing from the sides, and more or less covering the 

 ventral half of the aperture; coils of genital tubes very 

 numerous and close. Externo-dorsal ray thin more espe- 

 cially at the root; spicules of the male barbed at ends. 



Necator americanus (Plate VIII, Figs. 1 and 3). Head 

 bent, strongly dorsally, small buccal capsule armed only with 

 semilunar" plates: male, 7 mm. to 9 mm. in length and 0.3 

 mrn. to 0.35 mm. in width; bursa shown in figure; spicules 

 long and slender, 0.92 mm. in length and terminate in 

 barbed points; female 9 mm. to 12.6 mm. in length; vulva 

 just in front of middle of body; position in host and life 

 history as in Ancylostoma duodenale. 



I. Family Strongylidae 



Cylindroid rarely filiform bodies; mouth usually with 

 wide buccal capsule and a ring of chitinous armature; 

 esophagus more or less enlarged posteriorly; male with bursa 

 and two equal spicules; females with two ovaries; vulva 

 situated medially or posteriorly; species as rule small. 



Termidens diminutus, Oesophagostomum brumpti, 0. 

 stephanostomum var. thomasi, 0. apiostomum, are parasites in 

 the large intestine of man and monkeys in Africa and South 



