148 T. B. ROSSETER ON HTMENOLEPIS UPSILON, 



kroge" that is, embryonic hooks he, Pagenstecher, assumed that 

 they were the product of the bursting of the separated terminal 

 segments of his worm, and he almost believed that his specimen 

 might be referred to T. microsoma. 



In the University Museum (Copenhagen) besides Creplin's 



specimens there are some specimens of tape-worms collected in 



Greenland by Pfaff and Olrik, who found them in large numbers 



in the intestine of Anas moUissima and on one occasion in 



Anas spectabilis. The majority of them were 12 mm. in length, 



and 0"5 mm. in breadth ; there were some that were 40 mm. long, 



but then they were in a very loose, flabby (slappet) condition. The 



rostellum w^as long, slender, claviform, and on the knob there were, 



according to Krabbe, ^Hen hooks whose length varied according to 



the different species of eider-duck they were taken from, viz. 0'037- 



0'061 mm. (Fig. 4a-c) ; yet there was no mistaking^ in spite of 



the difference in size, that they belonged to one and the same 



species of tape-worm. Segmentation commences close behind 



the head. The number of segments was seldom more thstn 



from 150-180; now and then, but this was rare, there were 



as many as 500 [this must have been in tlie 40 mm. worm] 



in the strobila. I never at any time met with a specimen with 



so small a number of segments as Pagenstecher gives, although in 



the remaining essentials they agree with his description. The 



genital apertures were unilateral. The cirrus was 0*084 mm. long, 



frequently extruded, thickened at its point, in some instances 



covered with bristles, or small thorns, at other times destitute 



of these, they having possibly fallen off during maceration after 



death. The last segments generally contained unripe eggs ; 



there were, however, individual specimens with fully developed 



eggs [no doubt the 40 mm. specimen with 500 segments], and 



when these were crushed by pressure, they w^ere squeezed out in 



the form of a wreath in a similar manner to that Pagenstecher 



has described with his specimen." 



Krabbe says that he himself took tape-worms from Anas 

 fusca and marila that he was unable to distinguish from the 

 above, but that in November 1867 he found them in large 

 numbers in Anas fusca. They were only 2 mm. long ; there were 

 as many as 60 segments in the strobila, 0-3 mm. in breadth. 

 There were ten hooks on the rostellum, 0-043 mm. long (Fig. id) ; 

 the genital apertures were unilateral, the male organ was with- 



