91] PROTEOCEPHALIDAE — LA RUE 91 



an elongated proglottid of the same worm the vagina may be straight 

 or nearly so. Thus far a sphincter vaginae has not been demonstrated. 

 The lumen of the vagina from its opening to the ovary is almost con- 

 stant in diameter. No receptaculum seminis has been demonstrated. 

 The ovary is bilobed as in other Proteocephalids. The lobes are thick, 

 heavy and long. In all dimensions they are much larger than in P. 

 fallax or P. duhius. They also have a different outline. In mature 

 proglottids they measure 0.510 mm. long while in ripe proglottids their 

 span may be as much as 0.918 mm. This is much greater than in P. 

 fallax or P. duhius and more nearly like the condition in P. percae. The 

 organs within the interovarial space have not been investigated. 



The vitellaria (Fig. 67) are coarsely follicular, lateral masses. The 

 follicles are much coarser and more numerous than in P. duhius or P. 

 fallax. The vitellaria are situated at a distance of 0.100 mm. from the 

 margin in mature and ripe proglottids. This is considerably farther 

 than in P. fallax and P. duhius and greater than in P. percae. The 

 uterus, a median tube in mature proglottids, is augmented in ripe pro- 

 glottids by 6-8-9-12 lateral outpocketings on either side. The pouches 

 (Figs. 66, 68) are long, reaching to the vitellaria, and are voluminous. 

 Sometimes the larger pouches are apparently subdivided by short septa. 

 For this reason the appearance of the ripe proglottid in toto prepara- 

 tions differs considerably from that of P. percae or P. duhius. The 

 embryo is surrounded by three membranes, an outer thin and hyaline, 

 a middle thick and somewhat granular, and an inner very thin mem- 

 brane immediately investing the embryo. The embryo varies from 

 ovoidal to spherical in shape. The measurements of four embryos may 

 be taken as fairly representative of the range of size — 0.0265 by 0.024 

 mm., 0.0212 by 0.0212 mm., 0.0265 by 0.0212 mm., 0.024 by 0.0212 mm. 

 The second membrane measures 0.037-0.040 mm. in diameter. The 

 outer membrane is very variable in size and in the material studied 

 almost impossible to measure on account of its collapsed condition. 



This species somewhat resembling P. percae and P. torulosus in its 

 outward appearance is distinguished from the latter by its fifth sucker, 

 its smaller suckers, its shorter length, its much more numerous lateral 

 uterine pouches, its fewer testes, and by the different arrangement of 

 testes. From P. percae it is distinguished by its more numerous uterine 

 pouches, its more numerous and larger testes, its much shorter cirrus- 

 pouch, and by the different relations of cirrus-pouch and vagina. From 

 P. duhius and P. fallax it is distinguished by its larger head, its pro- 

 glottids of greatly different proportions, its more numerous and larger 

 testes, by the greatly different cirrus and cirrus-pouch, by the different 

 relations of the cirrus-pouch and vagina, by the differently placed coils 



