38 



ILLINOIS BIOLOGICAL MONOGRAPHS 



[38 



Specific Diagnosis: Characters of the genus. Very small cestodes. 

 Length as much as 35 mm. or more. Breadth 0.8 mm. Proglottids few, 

 15-25. Segmentation indistinct. Proglottids attached by their full 

 width. First proglottids broader than long, 0.20 mm. broad by 0.075- 

 0.080 mm. long. Mature proglottids about 0.18 mm. long by 0.370 mm. 

 broad. Ripe proglottids 0.48-0.66 mm. long by 0.425 mm. broad. Head 

 small, 0.090-0.120 mm. broad or perhaps a little more, not always well 

 set off from neck. Suckers 0.042-0.055 mm. in diameter. No fifth 

 sucker present. Neck to first traces of segmentation about 1.0 mm. long. 



Genital organs as in genus. Genital sinus marginal, irregularly 

 alternating, situated near middle of segment on a papilla-form promi- 

 nence. Cirrus-pouch about 0.130 mm. long by 0.032-0.040 mm. broad, 

 reaching about Yz-Va across the breadth of the proglottid. Cirrus-canal 

 much coiled in cirrus-pouch. Vas deferens forming mass of eccentric 

 coils. Testes in two layers, about 75-90 in all. Vagina anterior to 

 cirrus-pouch. Sphincter vaginae weakly developed. Receptaculum 

 seminis present. Vitellaria made up of quite compact follicular masses, 

 in lateral fields. Ovary bilobed, connected by an arched mid-piece. 



