409] PSEUDOPHYLLIDEA FROM FISHES— COOPER 121 



is no dense layer of nuclei just within it, as indicated in figure 96, while the 

 retractor fibres and small amount of parenchyma are quite loosely arranged. 



From its opening immediately behind the cirrus-sac, the vagina passes 

 downward and backward among the coils of the uterine duct and joins the 

 oviduct at the dorsal edge of the ovary just a short distance from the oocapt. 

 At the middle of its course it is IS/z in diameter. The ovary is from 0.45 to 

 0.55mm. wide, about 55^ long and 0.18mm. deep, being thus considerably 

 flattened anteroposteriorly. The spherical ova in the isthmus have an average 

 diameter by 13ju. The oocapt is 30ju in diameter, while the oviduct at the 

 point of union with the vagina is often slightly narrower than the vagina, in 

 fact about 10/x. Large right and left vitelline ducts unite in the median line 

 to form the yolk sac which is 1 75 by 65/^ in size. The vitelline follicles with max- 

 imum lengths, widths and depths of 45, 80 and 85^4, respectively, number from 

 450 to 720, or on the average 570 for each proglottis, as calculated by Matz's 

 method. They are not separated into two fields on each surface but strongly 

 united around the reproductive apertures, unlike the B. daviceps of Matz, the 

 two ventral fields of which were only weakly united while the dorsal were 

 strongly so. The shell-gland is posterodorsal and on the other side of the 

 median line from the vas deferens. The uterine duct is so voluminous (Fig. 

 72) that it crowds the uterus-sac and vas deferens to the other side of the median 

 line. It alternates irregularly from right to left, as do the latter. The sac 

 itself is situated in the anterior half of the proglottis where it is somewhat 

 flattened in the longitudinal direction and constantly occupies one-third of 

 the transverse diameter, as shown in Matz's Fig. 15. The openings, each 

 about 30/1 wide, form a zig-zag ventral row, since they are not exactly in the 

 median line but as much as 0.3mm. apart. Apart from being somewhat ragged 

 or villous they are not specially noteworthy. 



While the eggs of the European form have been given as from 56 to 60^ in 

 length, they were here found to be from 58 to 63/x long by 37 to 40^ wide when 

 measured in the formol in which the specimens were preserved. They are 

 light in color and so do not shov/ thru the body-wall as in B. scorpii. 



From the above comparison it will be seen that altho the individuals from 

 Eiipomotis gibbosus (those from which the data were taken) do not exactly 

 agree with the European species, they are sufficiently close to justify their being 

 considered the same. This was made more certain to the writer by the exam- 

 ination of some fragments of the European form, obtained by Professor Ward 

 from Dr. 0. Fuhrmann of Neuchatel, Switzerland, who took them from Anguilla 

 vulgaris in "North Germany." But it should be stated that in the latter 

 material the cirrus-sac and ovary are smaller and the uterus-sac much larger, 

 occupying more than half the diameter of the proglottis in many places; or, the 

 reproductive organs seem to become mature relatively earUer, differences in 

 degree of contraction and relaxation being taken into consideration. 



The material studied consisted of No. 289 of the writer's collection from 

 Anguilla rostrata, Nos. 17.33 and 16.456 from the collection of the University 

 of Illinois, the former from Eupomotis gibbosus and the latter from Anguilla 



