48 HELMINTHOLOGY 



EXERCISE 25b 



OTHER ASCARIDJS 



A. Study mounted specimens of Oxyuris vermicularis, the 

 pinworm of man, noting, 



a. The length in millimeters. 



b. The form of the body, tapering from the middle toward the 

 blunt anterior end, with thrice papillated mouth, and terminat- 

 ing posteriorly in a fine pointed tail. 



c. What are the sexual differences? 

 Draw male and female specimens. 



B. Examine specimens of Oxyuris curuula of the horse, and 

 the long-tailed species of the same host, Oxyuris mastigodes. 



C. Study mounted specimens of Heterakis papillosa, the 

 caecum worm of the hen. 



a. Notice the three-lobed lips or papilla. 



b. What is the average size and form of this species? 



c. Examine male specimens, locating the two posterior 

 spiculce. 



Draw male and female specimens. 



EXERCISE 25c 



THORN-HEADED WORMS 

 PHYLUM NEMATHELMINTHES, CLASS ACANTHOCEPHALA 



The thorn-headed worm of swine, Echinorhyncus gigas. 



A. Characteristics of Acanthocephala. Ascaris-like worms, 

 with a rostrum covered with recurved hooks; intestine absent. 



B. Echinorhynchus gigas. Examine specimens of the thorn- 

 headed worm of the pig for the following characters: 



