272 ILLIXOIS BIOLOGICAL MONOGRAPHS [272 



been observed. As the cirrus appears in the cirrus-pouch it is weakly- 

 muscular, not large, and is not armed. Probably when evaginated it 

 would be long, slender, and without a thick base. 



As seen in a toto preparation the female organs appear to be ar- 

 ranged in general as in the Proteocephalidae but a careful com- 

 parison of this species wuth any Proteocephalid reveals striking differ- 

 ences. The vagina (Fig. 95) always lies anterior to the cirrus-pouch 

 and it never crosses the latter nor does it cross the mass of coils of vas 

 deferens except in rare cases and then it crosses on the ventral side of 

 only the most anterior coils, Monticelli states that it crosses the coils 

 of vas deferens dorsally. The opening of the vagina is always clearly 

 anterior to the opening of the cirrus-pouch. In a number of species of 

 Proteocephalus and also of Ophiotaenia the opening is dorsal to the 

 cirrus-pouch, and the writer is inclined to believe that if the remaining 

 species of these genera were carefully investigated with that point in 

 view many of these too would show the opening of the vagina dorsal to 

 the cirrus-pouch. Near the vaginal opening is a weak sphincter vaginae. 

 Beyond the sphincter the lumen of the vagina dilates slightly for a dis- 

 tance, perhaps 0.3 mm., then it is constricted. After arriving in the 

 mid-field of the proglottid the vagina again dilates considerably. This 

 dilatation persists through several curves and coils until the vagina is 

 just about to enter the interovarial space when the vagina is greatly 

 constricted. The dilated region is the receptaculum seminis which is 

 much more marked than in any species of Proteocephalus observed by the 

 writer. As shown in transections (Fig. 94) the vagina, except its be- 

 ginning portion, lies within the internal layer of longitudinal muscles. 

 In this respect Monticellia coryphicephala agrees with the Proteocepha- 

 lidae. 



The ovary (Fig. 95) is posterior and bilobed. A narrow, thin raid- 

 piece connects the lobes which are long and broad. From the dorsal 

 surface of the distal region of each lobe rounded prominences arise and 

 extend toward the dorsal surface of the proglottid. Many of these 

 prominences when observed in toto preparations seem to have no con- 

 nection with the ovary and are readily mistaken for testes but when 

 studied in transections they are seen to be a part of it. ]\Ionticelli 's 

 drawing which is reproduced (Fig. 186) does not truly represent this 

 appearance. These dorsal prominences and the greater part of the 

 ovarian lobes (Fig. 96) from which they arise lie in the cortical paren- 

 chyma outside of the internal layer of longitudinal muscles. The mid- 

 piece and part of the lobes of the ovary lie within the muscular sheath. 

 Monticelli (1891) failed to point out this condition. Here is a relation. 



