242 ILLINOIS BIOLOGICAL MONOGRAPHS [242 



the interovarial space. The uterus is a median tube from which arise 

 on either side many lateral pouches; 20-25 are figured in Schwarz's 

 drawing. The ovary is relatively large and its lobes are somewhat 

 wing-like in shape. The eggs are provided with two membranes. No 

 processes arise from the outer one. No measurements of the eggs were 

 given by Barrois or Schwarz. 



The species is clearly differentiated from the other large species of 

 the genus by the size and shape of the head and suckers. The relations 

 of the cirrus and cirrus-pouch vary greatly from the plan common to 

 the other large species of the genus. 0. trimeresuri which has the same 

 relations of cirrus and cirrus-pouch is considerably smaller. 0. grandis 

 resembles it in having the same host species and in being of large size. 

 0. grandis has, however, a very much smaller head which is not readily 

 distinguished from the strobila. It has much smaller suckers and 

 greatly different relations of cirrus and cirrus-pouch. Its cirrus is 

 short and thick. It also has very many more uterine outpocketings. 

 0. marenzelleri is not to be mistaken for 0. racemosa, 0. nattereri, 0. 

 pigmentata, or 0. perspicua on account of its much larger size. 0. fila- 

 roides and 0. lonribergii being from Amphibia and also being much 

 smaller cannot be confused with 0. marenzelleri. 



OPHIOTAENIA GRANDIS La Rue 

 [Figs. 38, 97-101] 

 1911 : Ophiotaenia grandis La Rue 1911 :481 



Specific Diagnosis: Characters of genus. Body very long (frag- 

 ments 200 mm.) by 2.75-4.25 mm. broad in region of ripe proglottids. 

 Neck 5-8 mm. long. First proglottids much broader than long; pro- 

 glottids with developing sexual organs quadrate or nearly so ; ripe 

 proglottids quadrate or much longer than broad. Head large, 1.0-1.2 

 mm. broad at base of suckers. No fifth sucker or rostellum, no hooks. 

 Suckers nearly circular, deep and muscular, measuring about 0.34 by 

 0.36 mm. Genital aperture marginal, irregularly alternating, situated 

 near middle of proglottid. No genital papilla but sometimes a deep 

 depression about genital pore. Testes large, numerous, 200-250 in num- 

 ber, arranged in two broad lateral fields. Cirrus-pouch 0.24-0.26 mm. 

 broad, 0.64-0.75 mm. long, length equal to %-Vs of proglottid width. 

 Cirrus short and heavy. Few or no coils of ductus ejaculatorius in 

 cirrus-pouch. Vagina anterior or posterior to cirrus-pouch. Sphincter 

 vaginae heavy. Uterus Math 40-60 lateral outpocketings on either side. 



