CHAPTEE XIX. 



PLATYHELMIA CESTOIDEA. 



CLASS IV. CESTOIDEA. 



GRADE A. CESTOIDEA MONOZOA. 



Order 1. Amphilinacea. 

 2. Gyrocotylacea. 

 3. Caryophyllacea. 



GRADE B. CESTOIDEA MEROZOA. 

 BRANCH A. DIBOTHRIDIATA. 

 Order 1. Pseudophyllidea. 



Fam. 1. Bothriocephalidae. 

 ,, 2. Solenophoridae. 

 3. Bothriomonidae. 

 4. Leuckartiidae. 

 ,, 5. Triaenophoridae. 



BRANCH B. TETRABOTHRIDIATA. 

 Order 1. Tetraphyllidea. 



Fam. 1. Tetrabothridae. 

 2. Gamobothridae. 

 Order 2. Diphyllidea. 



Fam. Echinobothridae. 

 Order 3. Tetrarhyncha. 



Fam. Tetrarhynchidae. 

 Order 4. Tetracotylea. 



Fam. 1. Ichthyotaeniidae. 

 ,, 2. Echinocotylidae. 

 ,, 3. Taeniidae. 

 4. Mesocestoididae. 



THE class Cestoidea, as known at the present day, may be 

 denned as follows : Platyhelminths in which an internal parasitic 

 habit has led to the disappearance of the alimentary canal from 

 every stage in the life-history. The ciliated covering, as well as 



