PROTEOCEPHALIDAE — LA RUE 



89 



The suckers are heavily muscled, deeply concave, small and nearly 

 globular in shape. Six suckers, four from one head and two from a 

 second, gave the following measurements: 



Suckers of Proteocephalus cernuae 



The range of length and breadth of the suckers is about 0.064-0.090 

 nun. A sucker in transverse section measured 0.074 mm. in diameter. 

 The sucker opening it will be observed is very small, 0.037-0.042 mm. 

 The fifth sucker which seems to be a true sucker is about 0.024 mm. in 

 diameter. Its cavity is very shallow. Because of the scarcity of mate- 

 rial no sections were made and its true structure could not be finally 

 determined. The neck in all five specimens is broad and thick, narrow- 

 est just posterior to the head. Here it measures about 0.3-0.39 mm. Its 

 length varies from 1.36-1.7-2.0 mm. from the tip of the head to the first 

 traces of segmentation. 



The total number of proglottids in one of the shorter strobilas was 

 52, in the longest, 66. The segmentation is not plain. The edges of the 

 chain are quite smooth except for now and then small folds which rarely 

 occur at the junction of two proglottids. The angles between proglot- 

 tids are scarcely noticeable. No longitudinal folds or furrows were 

 seen. The first proglottids are much broader than long. In one speci- 

 men they measured 0.425 mm, broad by 0.085 mm. long. As the pro- 

 glottids become older they increase both in length and breadth. In all 

 but a very few ripe proglottids the breadth exceeds the length or the 

 segments are nearly quadrate. Mature proglottids are broader than 

 long, about 0.476 mm. long by 0.816 mm. broad. Ripe proglottids meas- 

 ure as much as 1.309 mm. broad by 0.68 mm. long or even 1.51 mm. 

 broad by 0.85 mm. long. One ripe proglottid which had discharged 

 some of its eggs measured 1.19 mm. long by 0.915 mm. broad. A true 

 functional end-proglottid, pointed at the posterior end, was 1.19 mm. 

 broad at the anterior end and 1.105 mm. long. The measurements given 

 are representative hence it will be noted that in general the breadth 

 of the proglottids exceeds the length. Only rarely and then only in old 



