CHAPTER IV 



THE STRUCTURE AND LIFE HISTORY OF A 



TAPEWORM, TAENIA PISIFORMIS 



(BLOCH 1780) 



TECHNICAL SUGGESTIONS 



The cosmopolitan Taenia piriformis (T. serrata) of dogs is the most 

 available material for this practicum. For the morphological study, 

 species of Multiceps or any of the other ta?nioid cestodes of the dog 

 are equally suitable. Proglottides of Tcenia saginata of man are 

 occasionally available from hospitals or may be purchased from 

 biological supply houses. 



Prepared slides of entire specimens of Tcenia pisiformis are instruc- 

 tive, but in general it is more satisfactory to have separate mounts of 

 developing, mature, and ripe proglottides and of the scolex. Direc- 

 tions for the preparation of these will be found in the Appendix, page 

 101. 



The hexacanth embryos are more readily studied in eggs of the 

 hymenolepid tapeworms. Rats and mice, including laboratory 

 varieties, are commonly infested by these worms, as are also chickens. 

 At most seasons of the year viscera of freshly killed poultry can be 

 secured from butcher shops and will yield ample material. 



Cystic stages may be, found in wild rabbits the country over, but in 

 order to insure a supply of suitable material, eggs from ripe proglottides 

 of Tcenia pisiformis should be fed to tame rabbits some two months 

 before needed. 



If there are facilities for experimental work, cysts of this age may be 

 fed to a dog at the time of the laboratory practicum and the adult 

 worms may be recovered in about six weeks. 



In lieu of rabbit material, cysts of Tamia tceniaformis of cats may 

 be found in the fiver of a high percentage of wild rats and mice. These 

 are readily developed in kittens. 



CHARACTERISTICS OF THE CLASS CESTODA 



The Cestoda, or tapeworms, are flatworms which have, 

 typically, the form of a ribbon made up of a large number 

 of segments, or proglottides (singular, proglottis). At one extrem- 

 ity is the organ of attachment, the scolex, provided with suckers 

 of varying form and number, and, in some cases, with hooks. 

 The body cavity is lacking, as is also the digestive tract. Food 



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