400 T. B. ROSSETER OX THE ANATOMY OF 



" Bidrag til Kundskab cm Fiiglenes Baendelormej" and states 

 that they have a mean measurement of 0" 020. mm. long. Krabbe's 

 •spechnen was 250 mm. long, and the proglottides, or segments, 

 1'5 mm. broad. 



A^on Siebold, Bavaria, took it from Meryus merganser L. 

 (Goosander) ; this specimen was but 120 mm. long and 1*5 mm. 

 broad. 



The genital organs were entirely overlooked by all those 

 naturalists who, from Bremser up to Krabbe, had found this 

 worm in the intestine of various aquatic birds, and even the 

 latter is very brief in his desciiption of these organs ; he 

 merely says, " Aperturae genitalium secundae. Longit penis 

 0*019 mm., latit 0*008 mm. Hamuli embryonalis longit 

 0-007 mm." 



This cursory description of Krabbe's is not even accompanied by 

 .«- sketch of the male organs of generation, and neither they nor 

 the female organs have ever been studied until the author of this 

 memoir undertook, as in the case of Dicranotaenia coronula, the 

 task of not only studying and describing the male and female 

 ■organs, but likewise illustrating them for the benefit of present 

 and future helminthologists who might undertake to continue 

 the work on the anatomy of those tape-worms which make 

 the Anatidae their final host. It is" evident from Krabbe's 

 brief description that the proglottides from which he drew his 

 conclusions, so far as the male genital organs and the hooks of 

 the oncosphere are concerned, were uterine segments ; the genital 

 organs, both male and female, were in a state of absorption and 

 much obscured by the formed uterus. 



Much doubt seems to have surrounded this particular 

 specimen. Rudolphi was inclined to think that it was identical 

 with T. trilineata of Batsch. Froelich thought that T. trilineata 

 was identical with T. lonyirostris Rudolphi, and catalogued 

 it as such ; whilst Dujardin came to the conclusion that T. 

 trilineata was simply a variety of Rudolphi's T. sinuosa. Krabbe 

 -simplifies the matter by dropping T. trilineata altogether out 

 of his catalogue and description of Avian tape-worms. I agree 

 with him, and think he was perfectly correct in so doing, more 



