96 







Each proglottis is budded from the neck of the scolex ; 

 as the number increases, the one first formed is pushed 

 further and further away and is the hindmost of the " chain." 

 The result of this intercalary mode of groAvth is a regular 

 gradation in size, shape and internal development. The 

 proglottids of the anterior portion of the " chain," being 

 the youngest, are narrow and short ; those of the middle 

 portion are larger, progressively square in shape and ap- 

 proaching -maturity ; while those of the terminal portion, 

 the oldest, have attained the lengthened rectangular 



Ring of hooks 



Sucker 



Proglottides 



FIG. 22. Scolex Of Taenia solium. (Highly magnified.) 

 After LEUCKART. 



form and are, most of them, ripe or gravid, ready to detach 

 themselves from the " chain." 



The tapeworm has no mouth and no alimentary canal ; 

 nourishment is obtained from the gut contents of the host 

 by absorption through the whole body surface (endosmosis). 

 The main nervous system consists of a commissural plexus 

 in the ecolex, and two longitudinal nerve-strands with 

 accessory nerves which pass through the whole series of 

 proglottides. The branching excretory system (flame- 

 cells, tubules .and collecting tubes) is also continuoua 

 throughout the entire worm. 



