FLAT WORMS AND THREADWORMS 



305 



in. 



Fig. 193. Other Nematode Parasites. 



I. a., Dracunculus (filaria) medinensis (female) , showing mouth and embryo. 

 b., Transverse section through adult female of I, a, showing many embryos 



in the uterus. 



II. Cyclops. This animal is the intermediate host of Dracunculus. 



III. Trichocephalus dispar (also called Trichuris trichiura) of the Family 

 Trichinellidae. a., egg ; 6., female ; c. f male attached to the intestine, showing the 

 long, slender, cephalic end buried in the submucosa ; sp., spicule. 



IV. Gigantorhynchus gigas, of the Class Acanthocephala, and Family Echinor- 

 hynchidae. A., two males and one female adult attached to the mucosa of the 

 intestine; B., eggs as seen in preparation; C., eggs as found in feces. (I, after 

 Bastian and Leuckart ; II, after Riley and Johannsen ; III, after Leuckart ; IV, 

 after Brumpt and Perrier.) 



in the male has two spiral turns. The female produces vast numbers 

 of young which enter the blood-stream through the lymphatics. Each 

 embryo is enclosed in a tiny shell about one-ninetieth of an inch in 

 length. They can thus pass through the capillaries quite readily. They 

 can be seen in a blood-drop under the microscope. As many as 2,100 

 embryos have been seen in 1 cc. of blood. 



Dracunculus medinensis is a peculiar worm, the female being about 

 a yard long. It is probably taken in with food. It makes its way down- 

 ward, and, when arriving at the ankle, usually pushes its head through 

 the skin, causing an abscess. As the eggs are then deposited, it leaves 



