38 DR. T. S. COBBOLD ON TKEMA.TODE PARASITES 



cause of their apparent absence. As regards size, the shriA'^elled 

 and shrunken character of the worm hardly permitted me to ascer- 

 tain the length with accuracy. It did not, however, when unrolled, 

 exceed one sixth of an inch at most, whereas some of batterer' a 

 specimens measured up to half an inch in length. The neck of 

 my specimen had also entirely lost that full and rounded charac- 

 ter which Diesing has so well figured and called skittle-shaped 

 (Jcegelformige). The ventral sucker is very nearly twice as large 

 as the oral sucker, the former measuring about the -^ and the 

 latter -^ inch in diameter from side to side. Diesing represents 

 the ventral sucker as perfectly circiilar ; but in Anderson's spe- 

 cimen this organ is broadly oval, the transverse diameter being 

 longer than the vertical. The central cup is somewhat less than 

 j^ij inch in breadth. 



The second trematode is one to which I am inclined to attach 

 more importance, partly, no doubt, on account of the circumstance 

 of its having been discovered by myself nearly twenty years since, 

 but chiefly because the possession of many specimens has enabled 

 me to acquire a much more accurate knowledge of its structure and 

 affinities than that obtained in the case of Distoma lancea. In the 

 22nd volume of the Society's ' Transactions ' I described a fluke 

 of which I had secured numerous examples from the peripheral 

 branches of the biliary ducts of a Porpoise {Phocoina communis). 

 The cetacean was shot by Mr. Jardine Murray in the Firth of 

 Forth in April 1855, and was regarded as a fine and healthy 

 animal. I mention this because the bile- ducts were diseased in a 

 similar way to that ordinarily observed in cases of rot affecting 

 sheep, cattle, and other animals infested by flukes. In the origi- 

 nal paper I did not perhaps lay sufficient stress upon the patho- 

 logical facts that were observed by me at the time ; but on refer- 

 ring to the manuscript notes still in my possession, I find it is stated 

 that "the liver-ducts were in sevei-al places thickened and knotted 

 near the surface of the organ. On opening these, they were 

 were found to be loaded with small distomata." It is added that 

 whilst the flukes were alive they displayed, under the microscope, 

 a " double and peculiar intestinal tube," the skin also being 

 clothed with spines which are arranged througliout with perfect 

 regularity. Unfortunately the day on which Mr. Murray sent 

 the Porpoise was a Saturday ; consequently my dissections were 

 hurried, and the specimens were placed in strong spirit, which im- 

 mediately destroyed their transparency. I was further embar- 



