DR. THEODOR NEUMANN. 241 



possesses a loDg tape-like body composed of single joints 

 and destitute of a special aiia:ieniary canal; each joint, 

 however, possesses an entirely independent sexual ap- 

 paratus with special orifices, while the other organs 

 stretch through the whole length of the body. This 

 chain of joints must be considered not as a single animal, 

 but as a colony of individuals, the joints, which are al- 

 ways in internal cuunection. These individuals, the pro- 

 glottids, may loosen themselves from the colony and live 

 an independent life for some time. The organization of 

 these animals is very simple, but sufficient for their 

 ne«ds, consisting only of muscles and genital organs. 

 After their separation from the chain these proglottids 

 stay in the alimentary canal of their host for some time, 

 move around and may even be r.ble to leave the latter 

 spontaneously (taenia saginata), while others are ejected 

 with the faeces and thus scattered around on fields, etc. 

 Such proglottids originate from the head or scolex of the 

 worm which sticks to the wall of the intestines, and re- 

 presents thus the organ of fixation for the whole chain, 

 the joints being saved the trouble of producing their 

 own. After the formation of one joint, another one is 

 produced between the first and the head; all others 

 originate in the same way, so that the first and oldest 

 joints are to be found at the remotest end away from the 

 head. They increase in size and thickness toward the end 

 and develop morf> and more their inner organs, the sexual 

 organs; a fructification takes place, and the eggs inside 

 wait until the joint leaves the host. The number of such 

 joints may vary greatly, likewise their form and size. 

 Several tape-worms never have more than four joints 

 (taenia echinococcus); others possess many hundreds. 

 Man has the largest tape-worms (taenia solium, the hook- 

 bearing, and taenia saginata, bookless); other large speci- 

 mens are taenia coenurus of the dog and bothriocephalus, 

 whose number of joints often reaches seven or eight 



17Q 



