88 ILLINOIS BIOLOGICAL MONOGRAPHS [376 



FISTULICOLA Liihe 1899 



Scolex unarmed, arrow-shaped (since the posterior borders of the surficial 

 bothria protrude comparatively strongly), may be replaced by a pseudoscolex. 

 Neck absent. Chain of proglottides very thick, so that transections may be 

 nearly circular. Segmentation strongly expressed, the individual proglottides 

 very short with leaf-like, free lateral portions. Longitudinal nerves strongly 

 approaching the lateral borders; individual testes, however, are also present 

 outside of them. Pronounced coiling of the vas deferens in its proximal por- 

 tion; the distal part near the cirrus-sac only weakly coiled. Receptaculum 

 seminis comparatively small and obscure, but at the same time sharply set oflf 

 from the narrow terminal portion of the vagina (the spermiduct), which in 

 contrast with the Ligulinae, Dibothriocephalinae and Cyathocephalinae is 

 comparatively long. Ovary and shell-gland, near the corresponding parts 

 of the female ducts, are, in consequence of the shortness of the proglottides and 

 the strong development of the uterus, forced away from the position which they 

 usually occupy in the Dibothriocephalidae, or towards the ventral surface or 

 the margin bearing the genital openings. Vitelline follicles extraordinarily 

 numerous, not confined to two lateral fields, but in the form of a ring, outside 

 of the longitudinal musculature in the free lateral leaf-like portions of the 

 proglottides. Uterus a comparatively wide, strongly coiled canal; that portion 

 near its opening very muscular. The eggs pass thru their embryonic develop- 

 ment (at least for the most part) in the uterus. 



T3^e species: F. plicatus (Rudolphi). 



