315] PSEUDOPHYLLIDEA FROM FISHES— COOPER 27 



(Fig. 78) and roughly divided into two parts by the lateral coils of the uterus^ 

 one part being immediately above the cirrus-sac and the other close to the 

 dorsal body wall. The duct attains a diameter of 35/i when filled with sper- 

 matozoa. Distally it expands into the very small (as compared to that of 

 Sell, solidus) seminal vesicle, situated close to the dorsal wall of the cirrus-sac. 

 The vesicle is from 65 to lOO^i in length by 40 to 90/i in diameter (156 by 86jLt, 

 Linstow), oval in shape, the narrower end towards the cirrus pouch, and pro- 

 vided with only a comparatively feeble musculature. The wall of the struc- 

 ture is richly supphed both internally and externally with nuclei which are 

 respectively those of the lining epithelium and the myoblasts, as in Schisto- 

 cephalus. The epithelium is strongly ciliated. The cirrus-sac (Fig. 78) is an 

 ovoid body, somewhat flattened dorso-ventrally and obliquely by the uterus, 

 and alternating irregularly from right to left, always occupying the opposite 

 side of the median line from the ovarian isthmus and the neighboring female 

 ducts. Its wall is quite thin, while apart from the cirrus proper which occupies 

 the distal two-thirds, the contents consist of loose parenchyma and only a few 

 retractor muscles. The measurements of the organ in sections are: dorsoven- 

 tral diameter, 185 to 215; width, 130 to 160; and length, 130 to 145^^; which are 

 quite at variance with Linstow's diameter of 53/x of what he described as a 

 spherical organ. Within the cirrus-sac the vas deferens is not sharply separated 

 into ejaculatory duct and cirrus proper, altho the latter is quite distinct, closely 

 coiled, and as much as 25yu in diameter. 



The vagina opens into the common genital cloaca, if one may use that name 

 for the depression mentioned above, in the median line and usually equidistant 

 from the openings of the cirrus and uterus. It passes dorsaliy thru the cortex 

 and the musculature with almost a straight course. Then within the medulla 

 it turns sharply posterolaterally, in which portion of its course it has a diameter 

 of from 15 to 30/^ (5/i, Linstow). Its thin lining of cuticula, directly continuous 

 with that of the genital depression, gradually passes into a nucleated epithelium, 

 in which no distinct cell boundaries appear, just within the cortex. Dorsal to 

 the ovarian isthmus it enlarges into an elongated receptaculum seminis which 

 has a diameter of from 75 to 90/i. Linstow described a spindle-shaped terminal 

 receptacle, 13ju in diameter, and an oocapt as follows: "dorsal von der Ver- 

 einigungsstelle der beiden Keimstocksfliigel liegt der ovale, 0.088mm. lange und 

 0.066mm. breite Schluckapparat " ; each of which, however, in comparison with 

 that described here by the writer and for Sch. solidus below, seems to have been 

 confused with the other. At least the oocapt of none of the bothriocephalids 

 described here is relatively so large as indicated by Linstow in his measurements 

 and in his figure, nor is the receptaculum as spindle-shaped as shown in the 

 latter. In this connection Kiessling described a swelling of the vagina, 46/x in 

 diameter, which contained spermatozoa. The spermiduct is so short and of 

 such a small cahbre that it is quite difficult to locate it in sections. After pur- 

 suing a horizontal course it unites with the oviduct a short distance from the 

 oocapt (Fig. 98) much as in Sch. solidus. It is from 20 to 25n in length and 

 6 to 12/i in diameter. The ovary is asymmetrical, as stated by Kiessling but 



