308 



FLAT WORMS 



The genus Hymenolepis has lateral genital pores, all of which are on the same 

 side. These lateral genital pores cannot be made out in specimens as ordinarily 

 examined. The head has four suckers and a rostellum, which is usually invaginated. 

 The rostellum has a single row of 24 to 30 booklets encircling it. Of the 150 to 

 200 narrow segments the terminal ones are packed with eggs which in the last two 

 or three seem to fill entirely the disintegrating segments. It would seem that the 

 fully mature segments disintegrate and in this way the eggs are set free in the 

 surrounding intestinal contents. 



The worms as found in fresh faeces after taeniacide treatment are frequently in an 



a- Laminated elastic cuticle 

 b fmer yermmal layer 

 c - Scoitr frte In cyst 

 d- Brood capsule 



;- Endogenous daughter cyst 

 - RufJurvd brood capsule 



-b. 



HYMENOLEPIS 

 DIMINUTA. 



FIG. 69. Other cestodes of man. 



advanced state of disintegration so that it is impossible to make out the head or 

 booklets. 



The eggs of this species are quite characteristic, there being two distinct mem- 

 branes. The inner one has two distinct knobs, from which thread-like filaments 

 proceed. The eggs of the H. diminuta have a thicker, striated, outer membrane 

 and there are no filaments. The eggs of the Dipylidium caninum are similar, but are 

 found in the faeces in aggregations several eggs in a packet. 



The dwarf tape-worm has been found to be the most common tape- 

 worm in the United States. Dr. Stiles found it in about 5% of children 

 in a Washington orphanage. 



