417 



are so numerous, and the length of the strobila so variable, 

 ranging from Rudolphi's T. longiceps, S mm. to *4 mm. long, to 

 one of Pfaff's new species taken from Anas glacialis, 420 mm. 

 long ; secondly, great difficulty is experienced in procuring the 

 scolex and hooks, even in young forms, owing to the attenua- 

 tion of the neck, causing the scolex, when the tract is emptied, 

 to be broken off and left behind in the mucous membrane or 

 mixed with the faeces; and, lastly, difficulties arise due to the 

 occurrence of aberrant and abnormal forms, such being probably 

 caused by cross-fertilisation. Passing on, the speaker proceeded 

 to consider and describe at some length the suggestions of 

 Weinland of Cambridge, U.S.A., in 1858, for the dismemberment 

 of the Linnean genus Taenia, and the establishment of the 

 genera Diplicanthus and Ui/menolepis. The difficulties raised, and 

 objections put forward, against the formulae of Weinland, and 

 an account of recent work on the genus Ilymenolepis followed, 

 and reference was made to the establishment by Bailliet of Paris 

 of the new genus Drepanxdotaenia. Mr. Rosseter then proceeded 

 to describe his methods of investigation. He said that to empty 

 the alimentary tract it is first uncoiled and the appendages 

 detached. The rectum is slit up and excised, the contents being 

 examined. Then, beginning close up to the gizzard, the intestine 

 is taken between thumb and finger, and by downward pressure 

 the contents emptied into a flat porcelain pan containing tap- 

 water. Whatever worms are visible, either to the naked eye 

 or with a watchmaker's glass, are picked up with hooked needles, 

 and placed in watchglasses containing an aqueous solution of 

 glycerine. They may then be examined with a 2 -in. objective. 

 To mount unprepared specimens in glycerine, they are 

 passed through different grades, and finally mounted in pure 

 glycerine. A cell is made with Bell's cement ; when partially 

 dry the quantity of pure glycerine required is placed in the 

 centre and the specimen immersed. After leaving it for a short 

 time it is arranged and covered with the cover-glass, letting the 

 glycerine, flow to the edges. The cover is held in position by 

 brass clips, and the superfluous fluid mopped up. Bell's cement 

 is run round the cover and left for, say, 24 hours. It is again 

 Journ. Q. M. C, Series II.— No. 64 31 



