THE LUNGWORMS 51 



c. What is the relative length of males and females? 

 Draw a complete specimen and make a separate drawing of 

 one showing the details of the buccal cavity. 



B. Examine a specimen of Monodontus trigonocephalus, the 

 hookworm of sheep. What are the main points of contrast with 

 the above? 



C. Study mounted specimens of (Esophagostomum colum- 

 bianum, the cause of nodular disease of the intestine of sheep. 

 How does this compare with the bovine-inhabiting species as to 

 relative size of buccal cavity? 



Draw the specimen. 



D. Another common Strongylid parasitic in the intestine 

 (fourth stomach) of sheep is H&monchus contortus, also a hook- 

 worm, but possessing a narrow buccal cavity. Notice the 

 twisted condition of the body in the female, due to ovaries 

 wound spirally around the intestine. 



Examine and draw specimens of male and female. 



EXERCISE 28 



THE LUNGWORMS 



PHYLUM NEMATHELMINTHES, CLASS NEMATODA, FAMILY 

 STRONGYLID^ 



A. Dictyocaulus viviparous (Strongylus micrurus) is the 

 lungworm of cattle. The worms inhabit the bronchia and lungs 

 of young calves, especially. Eggs are deposited in the lungs and 

 air passages and are coughed out by the host. 



a. Examine a portion of the lung of an infested calf in which 

 the worms are present in "pockets." If available examine an 

 infested lung which has been cut open. What can you say about 

 the distribution of the worms in the lung? Strongylosis is the 

 term applied to this infestation. 



