TAPE-WOEMS OF THE SUB-FAMILY AYFrELLIXlXiE. 317 



A Monograph of the Tape-worms of the Sub- 

 family Avitellininse, being a Revision of the 

 Genus Stile sia, and an Account of the His- 

 tology of Avitellina centripunctata (Riv.). 



By 

 LiCWis Henry Ooiigh, Ph.D., 



From tlie Zoological Laboratories of the Universities of Basel, Switzer- 

 land, and of Leeds, England. 



Witli Plates 12-14 and 6 Text-figures. 



The following paper was commenced at Leeds ; it was 

 originally iniended only to give an account of the anatomy 

 of Stilesia liepatica, Wollfhugel^ which has been very 

 imperfectly known until now, as much of the original 

 description is not only incorrect but actually misleading. 

 That section of this paper treating of Stilesia hepatica, 

 Wollfhiigel, was prepared at Leeds. I am much indebted to 

 Prof. Garstang for his hospitality in placing his laboratory 

 at my disposal and for the encouragement 1 received from him, 

 and desire to express my thanks to him for it here. 



As I was spending the winter at Basel, Switzerland, 

 Prof. Zschokke kindly offered me a table in his laboratory, 

 and suggested extending the scope of the paper I had com- 

 menced at Leeds so as to cover all the known species of the 

 genus Stilesia; he also helped me to bring together the 

 material required in order to make the paper complete. Its 

 scope was again extended to include an account of the 

 histology of Avitellina (Taenia) centripunctata (Riv.), 

 on account of several histological peculiarities of the worm, 

 which seem to throw a new light on the problems connected 



