52 HELMINTHOLOGY 



b. Study a mounted specimen under a low power. Note the 

 presence of six circumoral papilla. 



c. In a stained female specimen note the presence of two 

 ovaries. 



d. In a mounted male specimen notice the presence of a pair 

 of caudal spicules. Are the spicules of equal length? Examine 

 the caudal membrane for ribs. How many ribs are there? 



Draw both specimens, showing details. 



C. Examine a slide with young and embryo Strongylids. 

 Draw an example of Strongylid larva. 



D. Study specimens of Strongylus ovis pulmonis, the lung- 

 worm of the sheep. Describe the specimen and determine main 

 points of difference as compared with the above species. 



E. Study specimens of Syngamus trachealis, the gapeworm 

 of chicks. 



Draw a specimen. 



EXERCISE 29a 



THE WHIPWORMS 



PHYLUM NEMATHELMINTHES, CLASS NEMATODA, FAMILY TRICHO- 

 TRACHELLID^ 



A. Characteristics of Trichotrachellidce. " Recognizable by the 

 oesophagus, which resembles a necklet of pearls; the anterior 

 part of the body is usually of thread-like slenderness, the pos- 

 terior part of the body, which contains the genitalia, is more or 

 less thickened; there may be no spicules or only one. There is 

 a single ovary; vulva situated at the border line between the 

 anterior and posterior parts of the body." (Braun.) In the 

 subfamily Trichurinae there is a single spicule in the male; 

 development is direct, without encysted larval stage; and eggs 

 pass out of the body of the host and do not hatch until taken 



