INTESTINAL HELMINTHIASIS. 



257 



and Trichodectes (flea and louse) of the dog.^ 2. Tœnia serrata, 

 which comes from the Cystieercus pisciformis of the hare and the 

 rabbit (liver, lungs, peritoneum). 3. Tœnia marginata, produced 

 bj the Oysticercus tenuicoUi of ruminants and pigs. 4. Tœnia 

 Ooenurus, produced by the Cœnurus cerehralis of ruminants. 5. 

 Tœnia Ecliinococcus, produced by the Ediinococcm polymorphus of 

 herbivorous animals and pigs. 6. JBothriocephaluSy very rare, found 

 by Krabbe in Iceland and in Greenland.^ 



B. In the sheep: 1. Tœnia expansa (which may reach a length 

 of 60 centimetres), the cause of epizootic helminthiasis of lambs, 

 and of many other species imperfectly known. 



0. In the HORSE : 1. Tœnia perfoUata, the most frequent. 



2. Tœnia pUcata. 3. Tœnia mamillana, very rare (common, how- 

 ever, in France), and only one centimetre long. 



D. In the ox : 1. Tœnia expansa. 2. Tœnia denticulata. 



3. Tœnia alba. 



E. In the goat : Tœnia expansa. 



F. In the cat : 1. Tœnia crassiooUis. 2. Tœnia elliptica, 



3. Boihriocephalus latus. 



G. In poultry : 1. Tœnia infundibuliformis (chicken and 

 duck). 2. Tœnia lanceolala (goose and duck). 3. Tœnia cuneata. 



4. Tœnia proglottina. 5. Tœnia Cestioillus. 6. Tœnia tetragona 

 (chicken). 7. Tœnia cantaniana (turkey). 8. Tœnia crassula 

 (pigeon). 9. Tœnia fasciata. 10. Tœnia setigera (goose). 11. 

 Tœnia trilineata. 12. Tœnia coronula. 13. Tœnia anatina. 14. 

 Tœnia gracilis. 15. Tœnia sinuosa. 16. Tœnia megalops. 17. 

 Tœnia oonica. 18. Tœnia imbutifonnis (duck). 19. Bothrioceph- 

 alus longicollis (chicken). 



Natural history. The Tsenias or Cestodes belong to the group 

 of Plathelminths. They form colonies {strobild)^ the different por- 

 tions of which are formed at the expense of the scolex (head), which 

 is the head of the whole colony. The ripe animalculi are designated 

 nnder the name of proglottis. The head possesses a retractile trunk 

 (rostellum), and it fixes itself upon the mucous membrane by means 

 of tentacles and hooks. 



Each segment is formed by an external muscular layer possessing 



1 Melnikow : Archiv fiir Naturgesch., 1869. 



2 The larva of the large Boihriocephalus (a species which is quite common in cen- 

 tral Europe) lives in various fishes. — n. d. t. 



17 



