232 



ZOOLOGY. 



can be distinguished, and a very large number of 



joints, of which the first 

 are very small and short, 

 while those which follow 

 get larger and larger the 

 further they are from the 

 head. The tapeworm at 

 first consists only of a 

 head which holds on to the 

 lining of the intestine by 

 means of suckers or simi- 

 lar structures. The hinder 

 part of the head next 

 elongates to form the so- 

 called "neck." and a 

 cross-wall is quickly de- 

 veloped a little way in 

 front of the hind end of 

 this neck. By this divi- 

 sion is formed the first 

 joint, which, though forth- 

 with tolerably indepen- 

 dent, remains attached to 

 the neck of the tapeworm 

 head, until a new joint 

 is separated off from the 

 hinder part of the neck, 

 immediately in front of 

 the first joint. Every 

 new joint is similarly 

 formed by the constric- 

 tion of the hinder part of 

 the neck. Each joint pos- 

 sesses a complete set of 

 hermaphrodite reproduo- 



Fio. 135.— FiEmasa^triata: bead, anda +nv<i rirfrnna • it ViopnmoD 

 numberotjoints,rcpre8entednaturalBlze. "^® Organs, 11 DCCOmeS 



sexually mature without 

 reference to other joints, breaks off, and creeps about. 



