147 



HYMENOLEPIS UPSILON, A NEW SPECIES OF AVIAN 



TAPE-WORM. 



By T. B. Eosseter, F.R.M.S. 



{Read Xovemher 22nd, 1910.) 



Plate 6. 



This pretty little worm was found by me last January parasitic 

 amongst the faeces of the intestine of a wild duck Anas boschas. 

 Out of the number of wild ducks and other Natatores whose 

 intestines I have examined this is the only instance in which I 

 have found it, and in this case they were very few in number. 

 Before describing this minute tape-worm, and with a view to 

 its identity, as the hooks on the scolex closely resemble those of 

 Taenia ruicrosoma, it were better that I gave a condensed account 

 from Krabbe of the history of that worm : Taenia microsonia was 

 discovered by Schilling in Greenland in 1823, who found it- 

 abundantly parasitic in the intestine of Anas moUissima. He- 

 submitted his specimens to Creplin, who, in Novae observationes 

 de Entozois Berolina, 1829, reported on them under the name 

 Taenia microsoma. Krabbe merely says that the genital pores 

 were unilateral and that the small head was hookless. Dujardin, 

 Hist, des Helminths, p. 610, No. 132, supplies us with a 

 little more information respecting Schilling's worm, and says 

 that " Creplin's specimens were very young, only 7-13 mm. in 

 length, as thin or thinner than a piece of fine thread ; the 

 cirrus was cylindrical, almost claviform. The form of the head 

 was variable; suckers large; proboscis or rostellum elongate- 

 claviform ; the neck and all the segments were very short." 

 To return to Krabbe : H. A. Pagenstecher {Beitrag zur kenntnis^ 

 der Geschlechts-organe der Tanien in Zeit. fur loissenschaftliche, 

 Zooloyie, 9ter Bd., Leipzig, 1858), states that he found smal^ 

 worms, consisting of 21 segments, parasitic in Anas boschas. 

 The rostellum bore ten small hooks ; the genital pores were 

 unilateral ; the cirrus hirsute ; the terminal segments con- 

 tained unripe eggs. They did not attain their maturity in 

 the strobila, but the segments burst and emptied themselves 

 into the intestine of the host, for in the intestine of the same 

 bird he had found them collected together in strings which he 

 compared with slugs' egg-7nasses ^^ hvilke han sammenligner med 

 Sneglen^s Aeggemasser " ; and as the eggs contained " Foster- 

 JouRN. Q. M. C, Series II. No. 68. 11 



