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ILLINOIS BIOLOGICAL MONOGRAPHS 



[144 



center. Suckers large, round or oval in outline, deep, directed outward 

 and anteriad. Length of suckers 0.300-0.400 mm. Fifth sucker vesti- 

 gial, deeply embedded in tissue of head. Proglottids closely joined to- 

 gether, corners rounded. Young proglottids 12-15 times broader than 

 long. Mature and ripe proglottids broader than long, about quadrate, 

 or rarely longer than broad. 



Genital sinus irregularly alternating, marginal, situated about end 

 of first fourth of the proglottid. Vagina opening anterior to cirrus- 

 pouch. Vaginal sphincter long and very thick. Receptaculum seminis 

 present. Uterus with 15-20 lateral outpocketings on either side. Cirrus- 

 pouch pyriform, muscular, 0.400-0.500-0.650 mm. long, reaching ^/y-Vs 

 across the proglottid breadth. Cirrus, when protruded, long and slen- 

 der. Ductus ejaculatorius much coiled. Vas deferens forming a great 

 mass of coils extending to, or past, the middle of the proglottid. Testes 

 70-100 in number, situate between vitellaria. Eggs provided with three 

 membranes. Outermost membrane hyaline, ellipsoidal, 0.036-0.043 mm. 

 in diameter; second membrane thick, granular, 0.022-0.024 mm. in 

 diameter; third closely investing the embryo; embryo 0.0168-0.018 mm. 

 in diameter. 



Habitat : Intestine of host. 



