32 



mentally. Disease sometimes fatal. See Ashford and Igaravidez, 

 '11; Stiles, '03, and the publications of the Rockefeller Sanitary 

 Commission. 



Description — Adults 7-11 mm. long, possesses a dorsal and a 

 ventral pair of lips, a prominent dorsomedian tooth and four lancets. 

 As in other Strongylidae, the bell-shaped caudal bursa of the male 

 is supported by ray -like thickenings which form the so-called "hooks". 

 Females contain segmenting eggs; vulva in the anterior half of the 

 body. 



Development — The thin-shelled eggs, 64-72/u. long by 36-40/-'- broad 

 are deposited in early segmentation stage, reaching the open with 

 feces. In warm weather larva 210/u. long will escape before end of 

 first day, or at any rate soon after. In a few days larva grow to 

 560-600ju. and molt; soon a second molt occurs but old larval skin is 

 not cast off. In this condition many live for four or five months. 

 Enters man either through the skin (causing the well-known "ground 

 itch" or, occasionally, with water or food. 



Prophylaxis — Avoidance of soil pollution; use of sanitary privies, 

 wearing of shoes. Medical treatment simple but should be under 

 control of a physician. 



Related species — Agchylostoma duodenale, the Old World hook- 

 worm of man long known as cause of "tunnel disease", "miners 

 anaemia", etc. Agchylostoma caninum cause of a pernicious anaemia 

 of dogs. 



Syngamus trachealis — The gapeworm of birds. Lives in the 

 trachea and large bronchi of many species of birds. Causes enormous 

 loss of young chicks and pheasants. See Theobald, '96; Megnin, '06. 



Description — Body cylindrical, red, head broad and truncated. 

 Mouth large, circular depression, supported by a circular capsule; 

 at the base of this capsule are six horny, pointed processes around 

 the opening of the oesophagus. Male from 2-6 mm. long, the female 

 varies from 10-20 mm. (Theobald). Mature male permanently 

 attached to the female, the two forming a V-shaped compound. 



Development — Eggs not laid but escape by the rupture of the 

 parents body, being coughed up by the birds. Develop in water or 

 damp ground in 7 to 40 days, according to temperature, and when 

 taken up by birds reach the air passages and develop into adults. 

 No intermediate host necessary, though embryos may remain alive 



