138 ILLINOIS BIOLOGICAL MONOGRAPHS [426 



third composed of very closely set "cirri" and an inner two-thirds, which 

 took the stain with great avidity, leaving only a thin outer Ughter part which 

 by its contrast in color with the cirrous stratum served to set the latter off dis- 

 tinctly from the much thicker inner and more homogeneous part. The cuticu- 

 la was not found to be in any way specially modified on the scolex, altho such 

 might be found to be the case in well-preserved material. It was naturally 

 retained in its entirety only within the bothria. 



Only in the smallest strobilae could the subcuticula be made out satisfactor- 

 ily. It is from 25 to 40ju in thickness, and composed of somewhat conical cells, 

 the inner ends of which are quite cylindrical while the outer are much branched, 

 divergent and interlacing. Hence the cyHndrical portions, proximal to the 

 nuclei and usually somewhat smaller in diameter than the latter, are seen to 

 stand out distinctly and quite separately from the miuch less dense underlying 

 parenchyma. The outer dendritic portions cannot be allotted with certainty 

 to their proper cell bodies on account of this com^phcated m.esh-work which 

 they form just beneath the cuticula, but they can be followed to the cuticula, 

 their attachment to which is readily seen. 



Chalk-bodies in the poorly preserved parenchyma are usually elliptical in 

 outline, with maximium lengths and widths of 18 to 26 and 11 to IS^i, respec- 

 tively. They are fairly niunerous and scattered thruout all parts of the 

 strobila, being most plentiful in the cortex of ripe proglottides. In the scolex 

 a ver>' few small ones are to be found only in the enlarged posterior portion 

 of the organ, where they are confined to the medulla, no doubt on account of 

 the great development of the musculature. They are also more numerous 

 perhaps in the medullary portion of the parenchyma of the anterior segments 

 than in the cortical region. In general it would seem that they are developed 

 in that portion of the parenchyma which is little occupied by other tissues 

 or organs, chiefly muscles or genitaha. 



The musculature of this species is very well developed and powerful. It 

 was described by Linton (1890:729); but since his description is somewhat 

 difficult to follow, the main features of its arrangement will here be given even 

 at the expense of reporting much that has already been reported. 



The frontal series is well developed and consists of two layers on each sur- 

 face of the strobila, an outer, just outside of the thick layer of main longitudinal 

 muscles, and an inner, just within this or bounding the very thin medullary 

 parenchyma outwardly, as shown in figure 87. In the anterior segments a 

 third series of frontal fibres appears as the posterior flaring border of the seg- 

 ment is approached. It forms a ring around the whole strobila, i.e., connecting 

 with its fellow of the opposite surface laterally, unlike the other two layers, 

 just within the subcuticula or a little more than half way from the outer edge 

 of the layer of main longitudinal fibres to the cuticula. This series as evidently 

 pointed out by Linton, divides just ahead of the bay behind the posterior 

 border of the segment, part of it going to the outer, posterior border and the 

 rest remaining within. While the latter as just indicated does not go far 

 posteriorly, the former passes to the hinder edge of the salient border. In 



