74 



ILLINOIS BIOLOGICAL MONOGRAPHS 



[74 



Measurements in mm. of seven scolices and suckers may be seen in 

 the following table : 



No. 



Breadth of head 



Length 

 of head 



Suckers, maximum 

 diameter 



Fifth 

 sucker 



1 

 2 

 3 



4* 



5 



6 



7 



0.187 mm. 



0.185 mm. 



0.170 mm. 



0.185 mm. 



0.204 mm. 



0.153 X 105 mm. thick 



0.187 X 0.153 mm. thick 



short 



0.085 mm. 



0.080 mm. 



0.064 X 0.064 mm. 



0.068 mm. 



0.082 X 0.074 mm. 



not observed 



0.079 mm. 



0.058 mm. 



There is here some discrepancy between Kraemer's figures and 

 those of the writer. This may be due to an error in manipulation, to the 

 fact that Kraemer happened to measure a very slender head, or that he 

 happened to measure it in the dorsoventral (the shorter) dimension. As 

 will be noted the diameter of the sucker as given by Kraemer is about the 

 size which the writer gives for the sucker opening. The head (Figs. 23, 

 150) is somewhat globular in shape. The suckers are situated at or 

 just above the broadest zone and they are directed somewhat anteriad. 

 In the writer's material the head is readily distinguished from the thin 

 neck. The neck is 0.076 mm. broad (Kraemer), or 0.136 mm. broad in the 

 writer's measurements. Kraemer states that it is long but he points out 

 that in stained preparations part of that which appeared to be neck 

 was in reality made up of- young proglottids. In glycerine mounts the 

 neck sometimes appeared to the writer to be as much as 6 mm. long while 

 in stained preparation 2.38 mm. was the maximum length. 



The first proglottids (Fig. 170) are about quadrate or they may be 

 longer than broad. Kraemer gives the following breadths for the various 

 proglottids : First long proglottids 0.228 mm. broad, the quadrate ante- 

 rior proglottids 0.532 mm., the sexually ripe mid-proglottids scarcely 

 2.0 mm., the ripest end-proglottids as much as 2.0 mm. The writer's 

 measurements of similar proglottids are as follows: The first proglot- 

 tids 0.136 mm. broad by 0.17-0.30 mm. long, quadrate mature proglottids 

 0.34-0.46 mm. broad by 0.34 mm. long, the sexually ripe proglottids, 1.19 

 mm. broad by 1.36 mm. long (only four proglottids of this size were 

 observed). The segmentation of the worm is indistinct, the margins 

 being quite smooth except for very slight indentations at the junction 

 of the segments. The segments are closely joined together. The genital 



*The opening of the suckers in No. 4 measured 0.042 mm. 



