818 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [100] 



specimens of different ages. The hooks in the smaller specimens are 

 relatively longer in proportion to the length of the bothria than is the 

 case in the larger specimens. In the smaller specimens the posterior 

 segments are slender, somewhat fusiform, tapering slightly towards 

 anterior end, more decidedly towards posterior end. In the larger speci- 

 mens the posterior segments are in general linear oblong. If these 

 differences should be found to persist in specimens with ripe proglot- 

 tides they should be separated iuto different species. 



The most conspicuous organ of the posterior segments is the cirrus. 

 It is near thejniddie of the segment, and, when retracted, lies as a 

 prominent pyriform or fusiform body near the median line. It may be 

 seen to be densely covered with spines in specimens placed in glycerine. 

 In specimens which measured not more than 4 mm in length and contained 

 only from sixteen to twenty distinct segments the cirrus could be dis- 

 tinguished in the last eight or ten segments. In oue of the larger 

 specimens, about 10 mm in length, one of the posterior segments .9 mm 

 long and .36 mm broad, somewhat flattened, the cirrus is unrolled until 

 it is nearly as long as the segment. The spiues in this iustance are 

 nearly all lost, a few patches of epidermal tissue bearing slender spiues 

 adhere to its surface. lu some cases the pyriform basal part of the 

 cirrus is protruded, and can be seen to contain the remainder of the 

 cirrus coiled up in the interior. The spines on the basal part of the 

 cirrus are short triangular, with broad bases and acuminate points. 

 They are about .005 mra in length and .004 mm in breadth at base. The 

 remaining spines are very slender, about .007 ,mn in length and .0005 ram in 

 breadth. 



In one segment I observed what appears to be the extremity of a 

 very slender vagina protruding as a vulva from the margin immediately 

 in front of the cirrus. The length of this segment was .8 mm , its breadth 

 ,36 mm 5 length of cirrus .8 mm ; diameter at base .08 mm ; at apex .018 mra . 

 The vulva protruded .035 mm from the margin of the segment, and was 

 at first .008 mm in diameter, enlarging to a funnel-shaped extremity 

 ,035 mm in diameter. 



No ova were found in any of the segments. The interior of the pos- 

 terior segments is filled with the spherical spermatic capsules of the 

 testes, about .03 mra in diameter. 



When sufficiently magnified, several bundles of longitudinal muscles 

 can be seen in the neck near the head. A specimen that had been 

 killed by flattening between two slips of glass and immersing in alco- 

 hol was stained with carmine, and then mounted in Canada balsam. 

 By this means the bundles of longitudinal muscles are well differen- 

 tiated. Of these there are eight; four larger median, and four smaller, 

 the latter arranged two on each margin. 



These bundles are distributed to the bothria and the anterior tri- 

 angular cushions which bear the supplemental disks. Longitudinal, 

 transverse, and diagonal muscular fibers can be distinguished in the 

 bothria. Their arrangement can not be made out, however, on account 



