9,'J 



ments are very short and flat uear the head, but concave or cup-like 

 toward the free end, each overhipping the succeeding, and all appearing 

 linear on the surface of the twnia. The terminal relaxed segments are 

 cuneate. The borders of segments nearest the head are slightly wavy 

 or crenate. They soon become fimbriate even in youngest twnia ; so 

 that the smallest specimen found demonstrated the fringed character 

 of the species. The flmbriiB may either be contracted when they are 

 stout and short, or relaxed when they are flaccid and proportionately 

 longer. They are obtusely pointed. Tne segmentation in contracted 

 specimens is made out with difiBculty. It is indicated by transverse 

 striaj. In relaxed specimens it is plainer. 



The sexual organs are symmetrically placed, two sets in each seg- 

 ment, each opening in a lateral pore. Each set of organs is composed 

 of a male and female portion, or is hermaphroditic. They begin to de- 

 velop at some distance from the head and attain maturity towards the 

 middle of the twnia. 



Besides being remarisable in the fimbriate character of its segments 

 this species is also peculiar in the form of its reproductive apparatus. 

 The male portion develops first and occupies the whole width of the 

 young segments. It consists of sacs connected by tubules with a large 

 tube which finally becomes the much convoluted efferent tube. 



The ovaries develop later, and are situated at each side of the seg- 

 ment. They are not shown in the plate. 



The uteri develop last. Each is made of a series of bags arranged 

 side by side in a fringe which extends along the top of the segment 

 from side to side. These bags open into a larger tube from which they 

 receive the developing embryo. The tube connects with the ovaiies. 

 The embryos develop in the uteri, and probably remain there until the 

 segments go to pieces on the ground and thus permit them to be scat- 

 tered. They are six-hooked and not essentially different from those of 

 other twnia. 



Occurrence. — This twnia is found in the duodenum and gall ducts of 

 sheep. The former is sometimes found containing from thirty to one 

 hundred specimens. More often, however, there are from two to thirty. 

 The gall ducts are frequently completely distended by the twniw, which 

 pack them so tightly that the parasites can not be withdrawn by pull- 

 ing without breaking. Occasionally one, or at the most two, may find 

 their way into the pancreatic ducts, which they also distend. They get 

 into these ducts when young and distend them as they grow larger. 



A few disjointed segments may be found below the duodenum, but 

 no entire individuals. Kearly every sheep of a flock will be infected. 



Distribution. — Twnia fimhriata, Diesing, the fringed tape-worm, is at 

 present the most common parasite of the sheep of our Western plains, 

 and causes by far the greatest loss of any intestinal parasite in this 

 country. 



As may be seen by inspection of the tables showing parasites found 



