324 LEWIS HENIiY TtOUGH. 



all the specimens tliat passed through my hands were invari- 

 ably single-pored. In 1908, in a paper read before the South 

 African Association for the Advancement of Science, at 

 Grahamstown, CO., I stated that Stilesia hepatica, Wolff- 

 hlio-el, was single-pored, and that the original description 

 given by the autlior was at fault. Since then, by the kind- 

 ness of Prof. Colin, I have been able to examine the type 

 specimens of Stilesia hepatica, Wolffhiigel. There is no 

 possible doubt ; the type specimens are certainly single-pored, 

 with irregularly alternating pores. The anatomy of the worm 

 differs considerably also in other respects from the data given 

 by Wolffhiigel. In the following the anatomy of the worm 

 is given entii'ely on my own observations on fresh material, 

 supplemented by re-examination of the type. 



The worm invariably inhabits the bile-ducts, never the 

 intestine. It occurs in sheep, goats, duiker (Cephalopus), 

 roan antelope (Hippo tragus equinus). Hippo tragus 

 sylvaticus mernensis, fide Fuhrmann, Jind various other 

 wild ruminants occurring in South, East, and Central Africa. 

 The scolex is almost invariably lodged in the peripheral 

 capillaries of the bile-ducts. The parasites are often present 

 in large numbers, dilating the bile-ducts; their presence 

 does not cause calcification of the ducts, as Distomum 

 hepaticum, L., does, but only a thickening of the tissues 

 of the ducts. They appear to do otherwise but little injury 

 to the host; almost all adult sheep in the Transvaal are 

 affected. 



Stilesia hepatica, Wolffhiigel, is probabh" primarily 

 parasitic in wild ruminants, and can be supposed to have 

 adapted itself secondarily to sheep. The absence of 

 records of the conspicuous parasite from other parts of the 

 world, its occurrence in the wild antelopes, which are so 

 characteristic of the Ethiopian region, and the wide range 

 in its choice of hosts, would seem to speak for the probability 

 of its not being originally a parasite of sheep. 



Stilesia hepatica, Wolffhiigel, is extremely contractile, 

 more so than most other cestodes I have handled hitherto. 



