230 ILLINOIS BIOLOGICAL MONOGRAPHS [230 



cirrus-pouch (Fig. 107) is large and very muscular. Its length varies 

 from 0.27 to 0.34 mm. Its breadth is about 0.136 mm. and its length, 

 according to Parona, is 0.33 mm. The ratio of the length of the cirrus- 

 pouch to the breadth of proglottid is 1 :4 or 2 :5. 



The vagina lies either anterior or posterior to the cirrus-pouch, but 

 it does not cross the latter. Its course after reaching the median field 

 is frequently quite sinuous. Near its opening (Figs. 106, 107) it has a 

 very heavy sphincter muscle. In some parts of the vagina its lumen is 

 narrow while in other regions it may be widely dilated. The lobes of 

 the ovary are flattened. They are more elongate and narrower than 

 in O. marenzelleri. The paired vitelline ducts cross the ovary on the 

 ventral side. The uterus in mature proglottids is a median tube ex- 

 tending the length of the proglottid. No ripe proglottids could be 

 examined so the number of lateral uterine out-pocketings could not be 

 accurately determined. The drawing, however, (Fig. 108) indicates 

 that probably about 20-30 lateral pouches would be developed on either 

 side. No ripe eggs were present in the material examined. 



The description and drawing of the mature proglottid shows this 

 to be a species which falls readily into the group of Proteocephalids 

 infesting snakes. The writer's description and drawings do not agree 

 very well with Parona 's except as to size, position of genital pore and 

 length and shape of cirrus-pouch. From his drawings which have been 

 reproduced (Figs. 192, 193) it appears that he has confused certain 

 organs. The lower portion of the uterus in his drawing is undoubtedly 

 the bilobed ovary. The position of the testes posterior to the ovary in 

 his figure cannot be explained except on the supposition that he mistook 

 parts of the organs of the interovarial space for testes. The sinuous 

 duct which he shows as the vas deferens extending back from the cirrus- 

 pouch to the ovary is not the vas deferens but the vagina which in fact 

 passes below the coils of vas deferens before reaching the middle of the 

 proglottid. The mass of coils of the vas deferens is poorly shown at 

 the inner end of the cirrus-pouch. The opening of the vagina, the 

 vaginal sphincter and the first part of vagina along the length of the 

 cirrus-pouch he has omitted altogether or he has confused these with a 

 part of the cirrus-pouch. The cirrus-pouch as he drew it seems to be 

 made up of lamellae. In a poor preparation the cirrus-pouch might 

 have had this appearance. The cirrus within the cirrus-pouch is not 

 properly delineated. The uterus in an early stage may possibly have 

 had the single anterior lateral pouch on either side as he has shown it. 

 The writer has not seen a proglottid as nearly ripe as this one was and 

 so is not able to judge as to the actual structure of the uterus. The 

 testes and vitellaria he (Parona) has omitted from his drawings. It 



