TAPE-WORMS 



229 



Representative Life-Histories 



Adult, Sexual, or Tape-worm 

 Stage. 



1. Tcenia solium, in man, with four 

 suckers and many hooks. The joints 

 are elongated ; the ripe uterus shows 

 coarse branching. 



2. TcBnia saginata, in man, with four 

 suckers, but no hooks. The joints are 

 markedly elongated ; the ripe uterus 

 has many slender branches. 



3. Bothriocephalus latus (Dibothrio- 

 cephalus), in man, with two lateral 

 groove-like suckers, but no hooks, with 

 less distinct separation of the pro- 

 glottides than in Tcenia. The joints, 

 which are short and wide, show less 

 distinct separation. The ripe uterus is 

 somewhat stellate. The total length of 

 the chain may be as much as 11 yards. 

 Common in Finland and Switzer- 

 land. 



4. Echinococcifer echinococcus, in dog, 

 wolf, jackal. Very small, with three 

 joints behind the head, which bears 

 four suckers and two rows of barbed 

 booklets. 



5. Tcenia ccenurus, in dog. 



6. Tcenia serrata, in dog. 



7. Dipylidium caniniim (T. cucumer- 

 ina), in cat and dog ; head with hooks 

 and four suckers ; joints ovoid, with 

 genital aperture at both margins. 



8. Moniezia, the broad tape-worm of 

 sheep and cattle. 



Non-Sexual, Proscolex, or Bladder- 

 worm Stage. 



1. Cysticercus cellulosce, in muscles of 

 the pig. 



2. Bladder-worm in cattle. 



3. The ciliated, free-swimming em- 

 bryo becomes a parasite in the muscles 

 of pike, trout, burbot, etc., but without 

 a distinct bladder-like stage. It is 

 worm-like in appearance, and called a 

 plerocercoid larva. 



4. Echinococcus veterinonim, in sheep, 

 cattle, pigs, etc., and sometimes in man, 

 producing brood capsules, which give 

 rise to many " heads." 



5. Cosmirus cerebralis, causing sturdie 

 or staggers in sheep, with numerous 

 " heads." Also in cattle, goat, horse, 

 etc. 



6. Cysticercus pisiformis, in rabbit. 



7. In lice and fleas. 



8. Life-history unknown. 



Zoologically the cestodes are interesting, on account of their life- 

 histories, the degeneration associated with their parasitism, the pre- 

 valence of self-impregnation, and the complexity of the reproductive 

 organs. Practically they are of importance as parasites of man and 

 domestic animals. 



Classification. — The class Cestoda includes a number of families : — 

 Cestodariidae. No joints, one set of gonads. 



e.g. Archigetes, Caryophyllceus, Amphilina, Gyrocotyle, 

 Bothriocephalidae. Two weak fiat suckers ; genital openings usually 

 on the flat surfaces. 



e.g. Bothriocephalus ; Ligula, with no suckers or joints but with 

 serial gonads. 



