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PAPERS READ. 



JOTTINGS FROM THE BIOLOGICAL LABORATORY 

 OF SYDNEY UNIVERSITY. , 



By William A. Haswell, M.A., D.Sc, Edin., 

 Challis Professor of Biology, University of Sydney. 



14. On a remarkable Flat-Worm Parasitic in the 

 Golden Frog. 



(Plate xx.) 



It is several years since my attention Avas first directed to a 

 remarkable worm living as a parasite in the common gold-and- 

 green frog (Hyla aiirea) ; but, though specimens have been met 

 with several times since in the frogs dissected in the laboratory, I 

 have rarely had the opportunity of examining them before they 

 had been to some extent broken or destroyed. Altogether I think 

 six or seven cases of frogs infested with the parasite in question 

 have been met with during the last three years out of at least 150 

 specimens dissected ; so that this parasite, though not uncommon, 

 is by no means so general in its occurrence in this species of frog 

 as Rhabdoneiaa, Distoma or Jlyxosporidiuni, all of which are to be 

 found in nearly every individual carefully examined for them. 



The worm at present under consideration occurs sometimes in 

 the subdermal lymph-sinuses — in some cases on the ventral, in 

 others on the dorsal side — or it is found between the superficial 

 muscles of the thigh or the leg, or (this I observed only in one 

 instance) in the pleuro-peritoneal cavity. 



It has the form and appearance of a long and narrow, trans- 

 versely ribbed white ribbon. The longest specimen — which still 

 had the appearance of being incomplete behind — was about two 

 inches in length when moderately extended, and about a tenth of 

 an inch in greatest breadth. Uninjured specimens showed inces- 

 sant and active movements. These consisted of alternate elonga- 

 tions and contractions of the body which were most marked at the 



