34 



FLAT WORMS 



These calcareous bodies are characteristic of cestode tissue. They have been 

 mistaken for coccidia. There is no mouth or alimentary canal in tape-worms, the 

 segments absorbing their nourishment through the general surface. 



A tape- worm is divided into the segment-producing controlling head and the series 

 of segments or proglottides together known as the strobila. The head and neck 

 together form the scolex. 



The head contains the central nervous tissue and the commencement 

 of the water-vascular system. 



DibothriocephaliA latua 



Taenia solium 



Taenia saginata 



FIG. 68. Adult and larval stages of cestoda of man. 



Tape-worm heads are provided with suctorial or hook-like organs, or both, to 

 enable them to hold on to the intestinal mucosa. 



The hooks when present on the anterior extremity of the head are carried by a 

 protrusible structure called the rostellum. 



The importance of the head is generally recognized by the well- 

 known fact that the permanent evacuation of one of these parasites is 

 only arrived at when the head as well as the segments is expelled. 

 Otherwise, additional segments will be produced. 



Even in tape- worms 25 to 30 feet in length, the head is no larger than a small shot. 

 It carries the suckers or booklets which best enable us to differentiate the different 



