102 A. p. THOMAS. 



laboratory, a cercaria, which has since been proved to be the 

 larva of the liver fluke. 



The reasons which led me to regard this as the cercaria of 

 Fasciola hepatica need not be explained here, as they are 

 given in another part of this paper. In a report in the Royal 

 Agricultural Society's ' Journar for April, 1881, I described 

 this cercaria as a new species, and at the end of the description 

 wrote as follows: — "The structure and habits of this cercaria 

 render it possible that it may prove to be the larva of Fasciola 

 hepatica, but want of material has prevented my testing the 

 question by giving the cysts to rabbits. I intend, however, to 

 pursue this case further," 



On Dec. 12th, 1881, a paper appeared in the ' Zoologischer 

 Anzeiger,' in which Professor Leuckart announced that he had 

 succeeded in infecting young specimens of L. pereger, but had 

 been unable to obtain the development of the expected cercaria. 

 He also made it known, for the first time, that the statement 

 made by Dr. Cobbold in the 'Times' for April 7th, 1880, was 

 founded on a private letter from himself, and that the announce- 

 ment that his researches pointed to L. truncatulus had 

 proved to be premature and incorrect, for on further examina- 

 tion of his snails he had found them to be not L. truncatulus 

 but L. pereger juv. 



In the first number of the ' Archiv fiir Naturgeschichte' for 

 1882, which, however, bears no further date, the same results 

 were given at greater length. Professor Leuckart stated that in a 

 number of specimens of L. truncatulus sent him by a friend 

 he had found three kinds of redise. One of these contained 

 tailless distomes, which, he held, probably belonged to the 

 developmental cycle of the liver-fluke. He considered this 

 supposition to be entirely justified until further results were 

 obtained. A second form was not absolutely excluded from all 

 connection with the liver-fluke, but no such statement could be 

 made with respect to the third form. But in this third form I 

 at once recognised the cercaria found by me at VVytham, of 

 which a description had been published some eight months 

 earlier. 



