THE HOOKWORMS 49 



a. Measure the length of the specimens. How do the sexes 

 compare in this respect? 



b. Examine the rostrum and note the position of the booklets. 



c. Examine a cross-section of this worm. 



d. How does this worm procure its food? 



Draw a specimen to show general form, and make a detailed 

 drawing of the rostrum, showing the booklets. 



C. Examine a specimen of one of the beetles which serve as 

 intermediary host, e. g. Melolontha vulgaris, the European May 

 beetle or a species of Lachnosterna. fe&A 



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EXERCISE 26 



THE HOOKWORMS 



PHYLUM NEMATHELMINTHES, CLASS NEMATODA, FAMILY STRON- 



GYLID.E 



A. Characteristics of Strongylidce. Nematode worms with six 

 circumoral papillae, with or without a buccal capsule, in either 

 case may have an armature of teeth or hooks. Females have 

 two ovaries, with genital pore usually posterior, but may be in 

 front of middle; oviparous, with direct development. Caudal 

 bursa of males is lobed, each lobe with supporting rays, and two 

 spiculae about equal in length. 



B. Ankylostoma duodenale is the European hookworm of 

 man. 



a. Measure length of several specimens, determining first the 

 sex. 



b. Just inside the oral aperture notice the presence of re- 

 curved teeth. How many teeth are there in all and what is the 

 arrangement? 



c. At the base of the buccal cavity there are also present 

 several chitinous processes. 



