120 ILLINOIS BIOLOGICAL MONOGRAPHS [408 



subcuticula is from 25 to 40^1 deep, and the nuclei of its cells are confined 

 to their central halves. No calcareous bodies were seen in the rather fine- 

 meshed parenchyma, altho according to Braun (1896:1262) such were found 

 by Klichenmeister in this species. 



The musculature is comparatively weakly developed. The frontal fibres are 

 fine, scattered thruout the medulla and between the longitudinal fibres; while 

 the same may be said of the sagittal series. The longitudinal fibres are com- 

 paratively few and widely separated from each other, and as stated by Matz, 

 "are not arranged in bundles. " 



The chief nerve strands, about 17/u in diameter, are situated distinctly dorsal- 

 ly in the medulla and between the lateral quarters of the transverse diameter 

 of the segment. 



Matz described two main excretory vessels, between which is located the 

 nerve strand, on each side of the body, while Dujardin had previously stated 

 that there were four on each side. In the sections made three were seen to 

 follow a constant course oh each side, the nerve strand passing between the 

 more median pair. They are shown in figure 85. The medianmost pair are 

 greatly flattened as they pass close against the uterus-sac somewhat ventrally. 



Up to the time when Diesing (1863:241) incorrectly described ths genital 

 apertures as marginal and alternating, the only references to the reproductive 

 organs of this species were to the uterus-sacs which, being gorged with eggs 

 in the posterior segments, could be seen thru the thin body-wall in the medial 

 line. Carus (1885:120) failed to correct Diesing's error, so that it remained 

 for Matz (1892:109) to give the first and apparently only adequate description 

 of the genitalia, dealing with, however, only the differences between them and 

 those of B. scorpii. The earliest traces of the reproductive rudiments appear 

 about 5mm. from the tip of the scolex while the first eggs in the uterus-sacs 

 come at about 55mm. While the opening of the uterus is well towards the 

 anterior edge of the segment, that of the genital cloaca is midway between the 

 anterior and posterior borders. There is no papilla, the opening being a low 

 funnel-shaped depression in which there is no distinction between the external 

 portion of the cloaca and the hermaphroditic duct. 



The number of testes as determined directly is from 50 to 60, while their 

 average lengths, breadths and depths are 52 to 63,u, 58 to 70;^ and 58 to 63;/ 

 respectively. The similar data as given by Matz are: number, 56, size 36 to 

 47/i. The vas deferens, about 20,u in diameter, forms a mass of open coils, 

 lateral to the cirrus-pouch and posterior to the uterus-sac, thus occupying the 

 opposite side of the median line from that accommodating the bulk of the uter- 

 ine tube. The whole mass of coils is about 0.35mm. wide and 0.07 long. En- 

 tering the base of the sac with a diameter of 8^i, it gradually enlarges until at 

 the cirrus proper it is twice that size. The proximal end of that portion 

 within the pouch, however, is often found enlarged to form a sort of inner semi- 

 nal vesicle. The cirrus-sac itself ranges in length from 127 to 145// and in 

 maximum diameter from 81 to 104. Matz gave the measurements as 109 by 

 64/1. In comparison with that of B. scorpii the wall is quite thin and there 



