220 ILLINOIS BIOLOGICAL MONOGRAPHS [220 



are the oocapt, ootype, and shell-gland. The uterus appears in mature 

 proglottids as a median tube from which later 15-20 lateral pouches 

 arise on either side. The ovarian lobes are fairly dense compact masses. 

 In many proglottids the ovary has a more elongated and pointed form 

 than Schwarz delineates it. The vitellaria are lateral, follicular masses, 

 reaching from the anterior end nearly to the posterior end of the seg- 

 ment. According to Schwarz the eggs have three membranes. The 

 diameter of the ^gg is 0.024 mm. The outer membrane of ripe eggs is 

 covered with fine booklets or processes which terminate in small knobs. 

 The writer was unable to observe these processes in his toto mounts. 

 Schwarz 's figure of the Qgg is reproduced (Fig. 194). 



This species is easily differentiated from Crepidobothrium gerrardii, 

 0. marenzelleri, 0. calmettei, 0. racemosa, 0. trimeresuri and 0. grandis 

 by its much smaller size, and from 0. perspicua by its slightly smaller 

 head and suckers, by its lesser number of smaller testes, its more volumi- 

 nous cirrus-pouch and its lesser number of uterine pouches. In many 

 respects 0. nattereri and 0. perspicua are quite similar. 0. nattereri 

 has a smaller head and smaller suckers than 0. pigmentata. Further 

 comparisons with 0. pigmentata can not be made because of the incom- 

 pleteness of the data on the latter. 



OPHIOTAENIA RACEMOSA (Rudolphi; 

 [Figs. 140, 191] 



1819: Taenia racemosa 



(?)1819: Taenia cpluhfi 



1845: Taenia racemosa 



1850: Taenia racemosa 



1898: Ichthyotaenia racemosa 



1898 : Ichthyotaenia racemosa 



1908: Ichthyotaenia racemosa 



1911 : Ophiotaenia racemosa 



Specific Diagnosis: Characters of genus. Length of strobila as 

 much as 160 mm., breadth about 1 mm. Length of ripe proglottids 

 about 2 mm., breadth 1 mm. Scolex easily distinguishable from strobila, 

 breadth about 0.54 mm. Suckers four, nearly circular, 0.27-0.30 mm. 

 in diameter. Genital organs as in genus. Testes about 100-120 in 

 number, 0.072-0.078 mm. in diameter, located in two broad fields which 

 tend to fuse at middle. Ductus ejaculatorius sinuous. Cirrus-pouch 

 long, reaching nearly to middle of proglottid. Vagina anterior or pos- 



