84 PARASITOLOGY. 
Acanthocephala (acantha—thorn; cephale—head) 
includes the genus Echynorhynchus, which infests 
the intestinal tract. 
Plathelmintha (flat—wide) includes the orders 
Cestoda and Trematoda. 
Cestoda (kesto—girdle) includes the family 
Taenidae and genus Taenia (tape worms) which 
in the adult state infest the intestines. 
The family Bothriocephalidae includes the genus 
Bothriocephalus, which passes the larval stage in 
fish. 
Trematoda (perforated) includes the families 
Fasciolidae, Paramphistomidae and Schistosomi- 
dae. 
The family Fasciolidae includes the genera Disto- 
ma and Paragonimus, which live in the liver and 
lungs. 
The family Paramphistomidae includes the genus 
Amphistoma, which infests the stomach. 
The family Schistosomidae includes the genus 
Schistosoma, which lives in the blood. 
CLASSIFICATION OF THE COMMON INTERNAL 
PARASITES. 
Discophori .............. 
ib Aen eee Gnathobdellidae 
Genus and Species. ............seceeseeeeeeeee Haemopis Sanguisuga. 
CASS. acetone Nemathelmintha.......... 
Spiroptera Scutata. 
Spiroptera Megastoma. 
Spiroptera Microstoma. 
