105] PROTEOCEPHALIDAE—LA RUE 105 



it passes posteriad in a long curve to the interovarial space. The vagina 

 lies just dorsal to the uterus. Very near the opening of the vagina a 

 short sphincter vaginae 0.020-0.026 mm. thick may be seen. The inner 

 surface of the vagina is apparently ciliated. A receptaculura seminis has 

 not been found, tho it may exist. The ovary (Figs. 69, 70, 72) is long 

 and heavy. It is somewhat arched in the more elongated proglottids and 

 more elongated and slender in the longitudinally contracted proglottids. 

 Frontal sections show the ovary to be made up of closely connected 

 tubes or branches. The vitellaria are long lateral follicular glands which 

 extend from the anterior end of the segment to the ovary but not beyond. 

 The vitellaria are more dense near the ovary. 



The coils of the vagina, uterine passage, oviduct, and the common 

 vitelline duct nearly fill the interovarial space. Here also are the oocapt 

 and ootype. The relations and connections of these various passages are 

 similar to those described by Benedict (1900) for this group. An ill- 

 defined uterine passage discharges into the uterus near the middle of the 

 segment. The uterus (Figs. 70, 71) in ripe proglottids has 4, 5, 7, 8 or 

 even 9 lateral outpocketings on either side. These come to fill up nearly 

 the whole ventral side of the segment. Schneider found but a single 

 uterine pore near the middle of the proglottid. The writer has found 

 this number to be correct for his specimens. Schneider measured 

 the eggs as follows: embryo 0.025 mm.; second membrane 0.045-0.050 

 mm.; outer membrane 0.090-0.125 mm. My measurements are made 

 from uterine eggs of alcoholic materials. The writer has already shown 

 (La Rue 1909) that the outer membrane swells up when it comes in con- 

 tact with the water. It is not certain that the middle one does this. The 

 writer's measurements of eggs from Schneider's material are as follows: 

 embryo alone 0.019; second membrane, 0.0264-0.029; outer membrane, 

 0.031-0.037 mm. Since the writer has had Schneider's own specimens 

 for examination he is inclined to believe that Schneider measured the 

 embryo plus its investing membrane. The eggs which the writer so 

 measured gave his figures almost exactly for the diameter of the embryo. 

 It is a matter of regret that there is not more strict unanimity in the 

 method of measuring and recording the measurements of cestode eggs. 

 The data comprised in the discussion of the preceeding pages regarding 

 P. oscellatus and P. percae are presented in tabular form on the next 

 page. 



