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of protoplasm ; but the few larger sections (of vas deferens 

 or of oviducts and uteri) have no rachis. The vas deferens 

 and oviducts contain free gametes ; the uteri contain the 

 fertilised eggs. 



State what you know about the Life ~ History of Ascaris 

 lumbricoides. How does this Parasite gain access 

 to Man ? 



The encapsuled eggs are passed out in the faeces of the 

 host and develop in moist conditions (in water or in damp 

 earth). No intermediate host is known. Probably the eggs 

 containing embryos are accidently swallowed with water 

 or by eating contaminated vegetables. 



State briefly what you know about the following Nematodes : 

 Oxyuris vermicularis, Slrongylus gigas, Sclero- 

 stomum, and Syngamus. 



Oxyurus vermicularis (the Pin- worm) is a common para- 

 site of Man (children especially). It occurs in the small 

 intestine (when young) and in the large intestine (when 

 adult). The female is tailed, and about 10 mm. in length ; 

 the male measures 3 or 4 mm. 



The movements of these worms, particularly at night, 

 cause intense anal irritation. The eggs may be conveyed 

 (on the fingers) from person to person, or by eating fruit, 

 vegetables, or other articles of food that have been con- 

 taminated ; and auto-infection is -caused in these ways. 

 Possibly the eggs are carried by flies. 



Strongi/lus gigas (The Giant Palisade Worm) lives as 

 *a. parasite in the kidneys of the dog, the horse, and other 

 animals ; it rarely occurs in Man. The fen? ale is nearly 

 a foot in length. 



Various species of Sclerostomum (Armed Palisade- worms) 

 are dangerous intestinal parasites of the horse. The em- 

 bryos of 8. armatum enter the mesenteric arteries and 

 cause vermiceous aneurisms. 



Syngamus Irachealis (the Red Gape-worm or Forked- 

 worm) lives in the trachea and bronchi of poultry and 

 game-birds, and is the cause of the devastating disease 



