84 



STERELMIXTHA. 



matter, which escapes when the worm is torn asunder (d) ; but 

 whether it possesses a true alimentary tube, is not as yet satis- 

 factorily determined. 



(115.) The Tania., or tape-worms, are among the most inter- 

 esting of the Sterelmintha, whether we consider the great size to 

 which they sometimes attain, or the singular construction of their 

 compound bodies. Several species of these worms infest the human 

 body, and many other forms of them are met with in a variety 

 of animals. They are usually found in the intestinal passages, 

 where, being amply provided with nutritious aliment, they fre- 

 quently grow to enormous dimensions, being not unusually 

 twenty or thirty feet in length, and some have been met with 

 much longer ; it is therefore manifest how prejudicial their pre- 

 sence must prove to the health of the animals in which they 

 reside, and we are little surprised at the emaciation and weak- 

 ness to which they generally give rise. 



The T<znia solium, the species most usually met with in the 

 human subject, at least in our own country, is that which we select 

 for description. The body of this creature consists of a great 

 number of segments united together in a linear series (Jig. 36) : 

 the segments which immediately succeed to the head are very small, 

 and so fragile that it is 

 rarely that this part of 

 the animal is obtained 

 in a perfect state ; they 

 gradually however in- 

 crease in size towards 

 the middle of the body. 

 Each segment of the 

 tape-worm might be re- 

 garded as a distinct ani- 

 mal, for every one of 

 them, with the excep- 

 tion of the smallest, or 

 those in the vicinity of 

 the head, is found to 

 contain a complete ge- 

 nerative apparatus ; yet 

 the alimentary tubes 

 are common to them 

 all, those of each joint 



Fig. 36. 



