439] PSEU DOPEY LLIDEA FROM FISHES— COOPER 151 



of this series are very scarce, confined to the anterior segments and very difficult 

 to distinguish from the longitudinal cuticular fibres. 



The nerve strands, each about 35^ in transverse diameter anteriorly and 

 85/x thick by 45/i wide in mature segments, are situated between the lateral 

 and median quarters of the transverse diameter of the strobila. Unlike con- 

 ditions in the foregoing species, they occupy either the whole of the dorsoventral 

 diameter of the medulla or are situated strictly in the median frontal plane, 

 depending on the degree of lateral contraction. 



In the anterior segments two main longitudinal excretory vessels are located 

 in the medulla between the nerve strands; while two others, much smaller and 

 outside of the latter, are somewhat difficult to follow. In mature proglottides, 

 however, all four vessels are fairly easily distinguished, especially in transec- 

 tions. 



"The cirrus and vagina open by a common aperture on the middle of one 

 of the flat surfaces of the body. . . . The vagina is behind the cirrus; in 

 some cases directly behind it, in others a little to one side or other of the median 

 line. " This was found to be in the main true, altho on close examination it 

 is to be seen that the common genital openings form a zig-zag row as in the 

 foregoing species. The uterus-openings, described as opening "externally 

 on the middle of the dorsal surface, " likewise alternate irregiilarly from side 

 to side. Furthermore, while the genital cloaca is situated at the middle of the 

 very short proglottis, the opening of the uterus -sac is in the anterior portion 

 of the segment, often being under the posterior border of the segment ahead. 

 The cloaca itself is very shallow in this species, the openings of the cirrus and 

 vagina being almost at the surface. There is no definite velum separating 

 an inner ductus hermaphroditicus from an outer cloaca as in B. manubriformis. 



In the sections made, the testes, divided into two fields on each side by 

 the nerve strand, were much compressed anteroposterior^ with average maxi- 

 mum lengths, breadths and depths of 25, 85 and 115)ii, respectively. On ac- 

 count of this crowded condition it was not found practicable to count their 

 number directly in frontal sections, but it was calculated to be from 75 to 90. 

 The vas deferens, averaging about 25^ in diameter, forms a number of 

 loose, open coils extending thruout the whole dorsoventral diameter of the 

 medulla on the side towards which the central end of the cirrus-sac is directed, 

 and alternating irregularly from side to side as does the uterus-sac, but being 

 constantly located on the opposite side of the median line from the latter. 

 As it passes into the base of the cirrus pouch it has a diameter of only 3/i. 

 In the proximal or central one-third of the sac it takes a few turns and then 

 continues as a straight tube, somewhat larger (15/i) and usually filled with 

 spermatozoa, the functional cirrus which is about S/x in diameter. The cirrus- 

 sac is elongate oval to cylindrical in shape, the slightly larger end is ventral, 

 and has a maximum length and a diameter of 230 and 60ju, respectively. It 

 is thus approximately only one-half as large as that of B. manubriformis; nor 

 does it extend ventrally past the lower edge of the layer of main longitudinal 

 muscles. Its wall, as shown in figure 89, is comparatively thin, as pointed out 



