90 ILLINOIS BIOLOGICAL MONOGRAPHS [378 



Cuticula 10/x in thickness, subcuticula 50 to 55^. Calcareous bodies 15 

 to 25 by 10 to 15pi in dimensions, mostly outside of the longitudinal muscles. 

 Latter not in bundles but distributed thruout the cortical parenchyma, separa- 

 ted into outer and inner groups only in young proglottides. Transverse and 

 sagittal fibres likewise diffuse, former more numerous, however, just outside 

 of the medulla. Chief nerve strand 45ju in diameter, situated far towards the 

 margin of the strobila on each side, passing dorsal to the cirrus-sac and vagina. 

 Excretory system in the form of a plexus of vessels ramifying thruout the whole 

 of the medulla, of which one just within the nerve on each side is small in 

 caliber but provided with thick muscular walls. 



No genital cloaca, but the vagina opens immediately behind the cirrus-sac, 

 the outer half of which forms a protruding papilla from 0.4 to 0.6rnm. in length 

 and with a marked constriction at its base. Uterus opening about half-way 

 between the median line and the margin bearing the other genital apertures, 

 and on the free posterior portion of the proglottis. 



Testes polyhedral in shape; closely arranged, forming a dorsal layer con- 

 tinuous from side to side but discontinuous from proglottis to proglottis; 

 90 to 130, 55 to 75 and 90 to 185u, in length, breadth and thickness respectively; 

 quite numerous outside of the nerve strands, at least 200 to each proglottis. 

 Vas deferens strongly coiled and compact in the median line, less coiled lateral- 

 ly; median and distal portions lined with ciliated epithelium; no special en- 

 largement at any point in its course to form a vesicula seminalis. Cirrus-sac 

 0.5 to 0.7mm. in length by 0.2 to 0.4 in maximum diameter; outer half or more 

 forming the pyriform, protruding cirrus, the cuticula over which is deeply cleft. 

 This functional cirrus may be augmented in length by the further evagination 

 of the cirrus proper from the papillary portion of the organ. 



Immediately within its opening the vagina is surrounded by a sphincter, 

 0.2mm. in diameter, which is followed by a slight enlargement of the lumen to 

 a diameter of 60ju ; much coiled laterally but straighter medially ; 20^1 in diameter 

 at the middle of its course; spermiduct inconspicuous. Ovary irregular in 

 shape, median in position and considerably depressed, 0.7mm. in transverse 

 diameter by 0.1 in thickness, isthmus prominent, ova from same 25/>t in maxi- 

 mum diameter. Oocapt 2S^l in diameter, oviduct 40ju. Vitelline reservoir 

 75/i in diameter when filled with vitelline material. Vitelline follicles irregular 

 in shape, very numerous; discontinuous from proglottis to proglottis, but form 

 a continuous layer laterally and dorsoventrally in the free posterior borders 

 of the segments. Shell-gland inconspicuous. Uterus in gravid joints occu- 

 pies almost the whole of the medulla; 0.16 to 0.20mm. in diameter at its middle; 

 the terminal portion quite muscular, and sharply separated from the duct 

 immediately before it, 0.2 to 0.3mm. in length by 0.10 to 0.15 in diameter; 

 opening irregular in shape and size. 



Eggs thick-shelled (2 to 4ju) with dimensions of 0.09 to 0.10 by 0.05 to 

 0.06mm. 



Habitat: In the rectum — less frequently in the stomach and anterior por- 

 tion of the intestine — of the host. 



