72 



ILLINOIS BIOLOGICAL MONOGRAPHS 



[360 



Testes ellipsoidal, 60 to 90/z in diameter, 80 to 120 in number, arranged in a 

 single layer in the medulla and interrupted only centrally. Vas deferens a 

 circular mass of coils, 0.25 to 0.30mm. in diameter dorsal to the uterus-sac, 

 or to one side of it. Seminal vesicle within the cirrus-sac, 50 to 60/i in diameter; 

 cirrus proper slender, 0.20mm. in length, 8 to 15yu in diameter. Cirrus-sac 

 elongate, flask-shaped, 0.35mm. in length, llO/x in maximum diameter. 



Vagina 15 to 20/x in diameter; passes to median line ventrally, then dorsal 

 to the uterus. Receptaculum seminis median, 90)u in diameter. Ovary reni- 

 form, tubulolobular, 0.45mm. wide and 0.18 long; isthmus thick, ventral. 

 Oocapt 40/i long and 18 in diameter. Two ventral vitelline ducts; common 

 vitelline duct IQfi in diameter. Vitelline follicles irregular in shape and size, 

 forming a continuous layer around the proglottis excepting for median circular 

 areas dorsally and ventrally. Shell-gland small, compact, 115 by 55ju. Uterine 

 duct with only a few dorsoventral coils near the median line. Uterus-sac 

 circular in outhne, 1.0mm. in diameter, divided by deep incisions into 5 to 8 

 pouches; openings opposite the genital cloaca or slightly behind its level in 

 gravid proglottides almost in the medial line. 



Eggs, 45 by 36ju. 



Habitat: Intestine of host. 



Tj-pe specimen: No. 4724, Collection of the United States National Museum. 

 Type locality: Ohio River, Washington, Pennsylvania. 



This species was originally described by Linton but with so little attention 

 to the internal anatomy tha t up to the present it has remained pretty much a 

 species inquirenda et incerta sedis, as pointed out by Liihe (1899c :40; 1900a: 

 106); altho Ariola (1900:440) placed it in the now obsolete genus Bothriotaenia 

 Railhet. 



Linton described the color of the living forms as " ... at first lemon- 

 yellow; after lying in water for a few minutes the bodies become colorless or 

 faintly bluish translucent, while the heads remained yellowish." Regarding 

 their method of attachment he said: "Two pits were found excavated in the 

 mucous and submucous layers of the pylorus near the spiral valve, in which the 

 heads of a number of Dibothria were inserted. The length of the worm was re- 



