245] PROTEOCEPHALIDAE — LA RUE 245 



tion and an examination of the figures makes it evident that the cirrus 

 and cirrus-pouch of the present species are very different from the same 

 organs in 0. marenzelleri with which this species is closely allied. In 

 that species there are many coils of the ductus ejaculatorius within the 

 cirrus-pouch, and the cirrus when protruded is thick at the base but 

 drawn out to a slender tip. Schwarz (1908) errs in saying that the 

 cirrus-pouch is evaginated in 0. marenzelleri. His own figures show the 

 cirrus-pouch in situ. In the present species the vas deferens is thrown 

 into numerous coils which serve as a vesicula seminalis. There are about 

 200-250 testes which are arranged in two lateral fields. The testes 

 measure 0.04-0.05 mm. broad by 0.075-0.100-0.125 mm. long. The vagina 

 opens to the exterior either anterior or posterior to the cirrus-pouch, 

 with almost equal frequency. Out of 45 proglottids examined on this 

 point the vagina in 21 cases opened anterior and in 24 cases posterior 

 to the cirrus-pouch. A heavy sphincter vaginae 0.095 mm. long by 

 0.150 to 0.160 mm. broad, including vagina, surrounds the vagina near 

 its opening to the exterior. The thickness of the sphincter alone is 

 0.040-0.070 mm. The vitellaria are follicular in structure, and lateral 

 in position. Each follicle measures about 0.015 by 0.030-0.035 mm. A 

 diagram (Fig. 99) made from a toto preparation shows that the arrange- 

 ment of the organs of the interovarial space is similar to that figured 

 for other Proteocephalids. The ovaries are thin dorsoventrally. The 

 mid-piece connecting the ovarian lobes is slender and long. The uterus 

 (Fig. 101) in maturing proglottids is a median ventral tube. From this 

 are developed 40-60 lateral pouches on either side. These are formed 

 by the method already described by La Rue (1909) for O. filaroides. 

 No eggs are passed into the uterus until the outpocketings have attained 

 a considerable size. Two or more preformed ventral uterine pores are 

 developed before many eggs are present in the uterus. The largest 

 number of the uterine pores in the material studied was eight. The 

 eggs taken from the uterus of alcoholic specimens are usually ellip- 

 soidal, measuring about 0.026 by 0.037 mm. over the outer membrane. 

 Spherical eggs measure about 0.032 mm. The second membrane is 

 spherical, 0.021-0.023 mm. in diameter. The third membrane closely 

 invests the embryo which is 0.015-0.016 mm. in diameter. Mature eggs 

 have smooth contours. There are no hooklets or holding organs on the 

 egg membrane as Schwarz (1908) figures for the eggs of O. nattereri 

 (Parona). 



The present species differs from O. marenzelleri (Barrois) in hav- 

 ing a smaller head, smaller suckers, larger proglottids, greater breadth, 

 more numerous testes and more numerous uterine pouches. The char- 

 acter of the evaginated cirri of the two species is very different. It also 



