158 ILLINOIS BIOLOGICAL MONOGRAPHS [446 



beiden sich hier vereinigenden Randfurchen herriihrt, wodurch ihre Rander 

 etwas erhabener werden. Die Griibchen sind kaum von der Grosse eines 

 Nadelknopfchens und tief in Kopfe, so dass es fast scheinen konnte, als waren 

 sie wahre oscula;" but his figure 26, very good in other respects, does not do 

 justice to his description of these terminal structures. Compare also Lonn- 

 berg's (1893: 15-17) B. neglectus, the figure for the scolex of which looks very- 

 much like B. crassiceps. 



There is no neck in this species, but segmentation begins immediately behind 

 the scolex (Fig. 48) and is complete thruout the strobila. These characters 

 were included by Liihe (1899:44) in the diagnosis of the genus: "Aussere 

 Gliederung vollkommen, ein gegliederter Hals fehlt. " As regards this quo- 

 tation, it would appear that the "gegliederter" is either superfluous or a lapsus 

 calami for " ungegliederter. " The anterior border of the first segment, a 

 greater part of which is obscured by the hinder edges of the bothria, is con- 

 stantly somewhat narrower than the latter, but its posterior border is usually 

 about the same width even in such contracted specimens (Fig. 29). Its out- 

 line is somewhat trapezoidal, while its length is slightly greater than that of 

 the segment immediately following. The breadth of this first segment varies 

 anteriorly from 0.40 to 0.92mm. and posteriorly from 0.65 to 1.16 — ^Linton's 

 measurements are 0.78 and 1.07, respectively. Following this the segments 

 are closely set, five to six times as broad as long, while their somewhat thickened 

 posterior borders protrude on either side (as well as dorsoventrally) so as to give 

 the strobila a serrate appearance (Fig. 48). It is here that the formation of 

 new proglottides takes place by the subdivision of preexisting segments. This 

 serrate appearance is also present in the posterior part of the strobila, where 

 the proglottides are quadrate to twice as long as broad. 



Posteriorly each serration does not necessarily define the posterior border 

 of a proglottis. This is due to the presence of spurious articulations, possibly 

 included in Wagener's "articulatio spuria." These are furrows which arise 

 laterally, where they do not stand out as distinctly, however, as the true pos- 

 terior borders of the proglottides, but do not pass to the median Une. They 

 are not present in all of the posterior proglottides nor are they symmetrically 

 arranged. In the following excerpt from his more complete diagnosis it is 

 to be seen that Rudolphi (1819:477) did not refer to these structures: 



"Articuli breves, margine posteriore incrassato utrinque exstante, quo 

 corpus serratum fiat. Articuli ceterum inaequales, ut passim augustiores et 

 longiores intercurrant. " F. S. Leuckart said only, "Die ersten Glieder 

 am Kopfe schmaler als die Ubrigen, dann folgen fast gleichbreite, 

 die letzte Halfte der Glieder breiter als lang, mit deutlichen, weissen 

 Ovarien," which statement refers to "der beschreibene nicht ganze Wurm 

 . . . 13^" lang." Diesing (1863:236) described the strobila as " . . . el- 

 lipticum, articuUs ad medium usque increscentibus, inde descrescentibus, 

 marginalibus posticis utrinque prominentibus, articulo singulo pUca transver- 

 sali diviso ..." The latter has reference obviously to Wagener's " articulo 

 spuria." It is also seen that, as regards the shape of the strobila, he 



