48 



THE TAPE- WORM 



small " head " and scolex are situated. The rest of the animal is called the 

 body or strobila. 



The top of the scolex is the somewhat conical rostellum, the base of which 

 expands into the rounded "head." The rostellum has a circlet of minute 

 recurved hooks, and the head bears four rounded suckers. By means of these 

 hooks and suckers the tape-worm attaches itself to the lining of its"[host's 

 intestine. 



The body or strobila is made up of a series of segments or proglottides. 

 These are narrower behind the head region and gradually increase in size towards 

 the posterior end. Each proglottis, when mature, contains a set of hermaphro- 

 dite reproductive organs. At first the male organs alone are developed, then 

 the female organs appear ; and later the whole segment, on the ripening of the 

 female organs, is filled with developing eggs or embryos, and only remnants of 

 the male and female organs, except the uterus, remain. 



Uterus 



Testis 



Ovary- 



Oviduct' 



Excretory canal 



Vas deferens 



-Penis 

 'Female genital 

 aperture 



Lateral 

 nerve 



Fig. 17.— a Mature Proglottis of Taenia solium ( x 6). 



A Typical Mature Proglottis. 



Examine a mature proglottis, which has been stained and mounted, and 

 note the following parts : — 



The Reproductive System : 



(a) Female organs. 



The ovary is paired and occupies the lateral posterior part of the proglottis. 

 Each ovary consists of a series of tubes in which the ova develop ; and these 

 tubes converge into a central tube leading from each ovary, the two tubes 

 joining to form the median oviduct. Occupying the middle of the anterior half 

 of the proglottis is the uterus, a branched tube containing the fertilised eggs. 



