107 



known as " gapes." The female is nearly an inch long ; 

 the male, which is about a fifth of that size, is generally 

 attached to the female, hence the name " forked- worm." 

 When mature and full of eggs the worms are coughed up ; 

 they decay and their eggs, scattered about the ground, 

 are swallowed by healthy birds. 



A species of Syngamus has been found in Man. 



Describe Ancylostoma duodenale and its Life - History. 

 How does Man become infected with this Parasite, 

 and what is the Result ? 



Ancylostoma (syn. Dochmius) duodenale, the " Hook- 

 worm " or Miner's Worn:, is a dangerous parasite of Man* 

 It is prevalent among the inhabitants of tropical countries 

 and commonly attacks ground- workers and miners through- 

 out Europe, Africa, China, and other parts of the world. 

 In America it occurs in association with the closely related 

 Necator americanus. 



The female is about 12 mm. in length ; the male measures 

 from 6 to 9 mm. and its body ends in a prominent expansion, 

 the bursa. The mouth is armed with two pairs of cutting 

 teeth, and by this means the worm attaches itself to and 

 feeds on the mucous membrane of the small intestine (jejunum 

 and duodenum). The fertilised, eggs are passed out in the 

 faeces and develop in damp soil. The larvae show dis- 

 tinct stages of growth with corresponding moultings of 

 the skin. 



There are two ways of infection : 



1. By taking food with dirty hands, or by eating pol- 



luted vegetables (a common source of ancy- 

 lostomiasis in Japan where human faeces are 

 used as manure). 



2. Through the skin. The mature larva has a mouth 



capsule with teeth ; it works its way through 

 the skin (of hands or feet) and, via the blood 

 circulation, ultimately reaches the small in- 

 testine. " Ground-itch " and other forms of 

 foot-sore in the tropics are attributable to this 

 invasion of the skin. 



