104 ILLINOIS BIOLOGICAL MONOGRAPHS [392 



numerous, as Lonnberg stated, in the cortical than in the medullary paren- 

 chyma. In the scolex, however, they are somewhat more numerous than in the 

 strobila, in both of which locations they attain a diameter of 13^. 



Lomiberg (1891:53) gave a good description of the musculature of the 

 species, while Lulie ( 1897a :747) referred to that of the posterior border of the 

 proglottis in the discussion of the arrangement of the muscles of the whole 

 order. In addition to corroborating the findings of these authors, it was 

 noticed by the writer that the fibres of the transverse series are mostly con- 

 fined to the very short regions between the sets of reproductive organs and 

 are most numerous just ahead of the prominent segmental furrows mentioned 

 above, this applying to both the inner and outer lots. Towards the median 

 line each layer of longitudinal muscles is about 35ju in thickness and composed 

 of bundles of various sizes, in which the fibres are very closely arranged. The 

 outer longitudinal muscles, the extension of which into the posterior borders 

 of the segments immediately behind the scolex are only wealdy developed, are 

 in the scolex confined almost completely to very thin bands situated close to 

 the cuticular musculature in the edges of the bothria, as described elsewhere 

 by the writer (1914a:92) ioxH. globuliforme. 



Lonnberg (1891:54) described the nervous system so well that little needs 

 to be added. The foremost four large branches from the brain complex were 

 not found to be relatively as large as those shown in Lonnberg's Figure la, and 

 the commissure appeared to be divided into two, not distinctly separated, 

 frontal strands, the whole depth of which, including the space between them, 

 was not as much as that shown in his Figure Ic. In the strobila the chief nerve 

 strands, each from 15 to 25/i in diameter, are situated towards the ventral side 

 of the medulla and at the junctions of the lateral and median quarters of the 

 latter, as shown in figure 84. 



The excretory system of B. scorpii was described in detail by Fraipont 

 (1881:8), while Lonnberg (1891:53) added some further notes on its structure, 

 the former, however, working on living material in which the canals are much 

 more readily seen. In good toto preparations the ''canaux descendants" 

 may be easily seen in segments showing the reproductive rudiments as well as 

 farther forward. Owing to a mere accident, temporary preparations showing 

 the details of the reticulum of descending canals in great detail were made by 

 the writer with more or less constant success. When some pieces of a strobila 

 were being transferred from synthetic oil of wintergreen to a slide for the pre- 

 paration of toto mounts by the further addition of xylol-damar, they suddenly 

 became opaque white and remained so for some time after the damar and cover- 

 glass had been added. This opacity was found to be due to air having been 

 drawn into the excretory canals not only thru their cut ends but thru the 

 foramina secundaria. But since the superficial reticulum and all the finer 

 canals were filled with air, nothing of the arrangement of the larger canals 

 could be made out until a short time had elapsed, or until the preparation 

 had been heated slightly. Then the air in the smaller canals became replaced 

 by the xylol-damar, and the larger canals stood out as very distinct silver 



