417] PSEUDOPHYLLIDEA FROM FISHES— COOPER 129 



testes and other median connections more numerous between the sets of repro- 

 ductive rudiments. In mature proglottides only the more regular ventral 

 vessels can be followed with any degree of satisfaction. As the vessels enter 

 the scolex, the dorsal series soon breaks up into an irregular plexus, consisting 

 of large branches and lacunae, situated more particularly in the large posterior 

 portions of the organ; while the ventral pair quickly diminish in size and 

 regularity of course, but do not lose their identity entirely until at least one-half 

 the length of the bothria is passed. In the youngest strobilas at hand what 

 was considered to be the "end proglottis" showed the excretory system as 

 terminating in an irregular plexus from which numerous foramina secundaria 

 passed to the exterior quite as in Fraipont's (1881, Fig. 8, Pi. II) view of 

 the conditions in B. scorpii. 



The genitalia have the general habit of the genus. The common genital 

 opening or cloaca, situated dorsally in the median line, is usually about half 

 way between the anterior and posterior borders of the proglottis, while the 

 uterus opening on the ventral surface is quite near the anterior border, so close 

 in fact that in much contracted strobilas it may be all but obscured by the 

 posterior border of the proglottis ahead. Unlike B. scorpii both openings 

 are situated at the bottom of comparatively deep depressions, as shown in 

 figure 102, that of the genital cloaca being usually circular in outline, about 0.10 

 mm. in diameter and 0.11 in depth. In some proglottides, however, it may be 

 so contracted longitudinally as to present a transverse diameter of 0.45inm., 

 with a length of only 0.04 and a depth of 0.13. The ductus hermaphroditicus 

 or secondary cloaca is very shallow in this species, and only about 55/x in dia- 

 meter. In most of the preparations made it was usually occupied by the tip 

 of the cirrus, when the latter was not extruded, the opening of the vagina form- 

 ing a very narrow crescent-shaped sUt close behind it. In some cases, how- 

 ever, both the cloaca and the ductus were so contracted longitudinally that 

 the tip of the cirrus was found almost inserted into the entrance to the vagina. 

 From this fact, together with the comparatively great depth of the cloaca in 

 such states of contraction, it is conceivable that self-impregnation may take 

 place; but nothing in the nature of a cloacal sphincter to assist in this function 

 is present. 



The testes are continuous from proglottis to proglottis in two lateral fields 

 separated by the median row of proximal organs of the reproductive system. 

 Since dorsoventrally they occupy almost the whole diameter of the medulla, 

 each is further separated into two more or less irregular fields by the nerve 

 strand. The more median field consists of little more than one longitudinal 

 row of the follicles. The number of testes is usually from 25 to 30 on each side, 

 with a variation of a few in either direction, thus making the total niunber 

 from 50 to 60 on the average. They are ellipsoidal in shape with their longest 

 axes transverse to that of the strobila, and attain dimensions of 0.1 10mm. in 

 width (in the transverse direction), 0.060 in length and 0.080 in depth. On 

 accoimt of their large size, as compared with that of B. scorpii, they are natural- 

 ly much more regularly arranged in the proglottis. 



