150 ILLINOIS BIOLOGICAL MONOGRAPHS [438 



Liihe (1899:43) sta.ted under his diagnosis of the genus that "Von weniger 

 gut bekannten Arten gehoren auscheinend noch hierher Bothriocephalus lacinior- 

 tus (Lint.) und occidentalis (Lint.)," Vv^hiJe Ariola (1900:415) included it in his 

 compendium of the known species. 



Since no scolex arid only very poorly preserved anterior parts of the stro- 

 bila were found in the above mentioned lot, Linton's description is here given 

 verbatim : 



"The bottle contained two fragments and portion of pyloric coeca of fish. 

 The fragments measured 190 and 310mm. in length, respectively. Another 

 fragment with scolex was found in one of the pyloric coeca; this was 115mm. 

 in length. 



. Head small, elongated truncate, and somewhat capitate, constricted near 

 posterior end with prominent posterior margin; fossettes coincide with flat sur- 

 face of body and extend posteriorly nearly to constriction; segments begin 

 immediately behind head, somewhat funnel-shaped, soon becoming densely 

 crov/ded and much broader, ten to twenty or more times as broad as long, 

 decreasing in breadth and increasing in length again toward posterior end. 

 Posterior segments in groups of three or four, namely, divisions between seg- 

 ments of contiguous groups more distinctly marked than between other adjacent 

 segments. 



Dimensions of head and segments: Length of head, 1.30mm.; breadth 

 of head, apex, 0.46; middle, 0.46; base, 0.40; breadth of first segment, 0.42; 

 length of first segment, 0.12; greatest breadth, 5.5; length of broadest segments, 

 0.25 ; breadth of posterior end, 2 ; length of posterior segments, 0.8. . . . 



The sides of the head which correspond with the lateral margins of the body 

 are medianly depressed toward anterior end." 



Concerning the cuticula nothing more can be said than that in the anterior 

 segments where it did not seem to be much eroded, it was found to be only 

 about 1.5^1 in thickness. The subcuticular cells are closely crowded together. 

 They form a syncitioid layer, in which the comparatively large nuclei (S/z in 

 diam^eter) stand out prominently, beginning about 35ju from the surface and 

 extending centrally to the vitelline glands. As pointed out by Linton, "Cal- 

 careous bodies are present in the central core [medulla] and sparsely scattered 

 elsewhere, but nowhere abundant. . . " The largest of them were found 

 to be 18/^ long by 13 wide, thus being within the limits of measurements of 

 those of B. mamibrijormis. 



In general the musculature is quite comparable to that of B. manuhriforniis. 

 There is a stratum of frontal fibres on each surface of the layer of longitudinal 

 fibres, but no third or outermost group in the anterior segments, doubtless 

 owing to the fact that the posterior borders of the latter are not nearly so 

 prominent. Both layers are rela,ted to the uteri and cirrus -sacs in the same 

 way. The sagittal fibres are much less numerous especially anteriorly. While 

 the main longitudinal muscles, arranged in quite the same manner and with 

 the same thickness, namely, 145^t, render the cross-section of mature segments 

 similar to that of B. manubriformis at first sight, the fibres of the external group 



