108 ENTOZOA. 



the numerical strength, of the flukes and roundworms. Upwards 

 of two hundred and fifty distinct forms have been described, but 

 it may be doubted if two hundred of these are really good species. 

 Assuming the latter to represent their number, the following 

 simple table of classification wiU conveniently embrace all the 

 species :— 



( TeeniadcB (Family I.) 

 CfiSTODA I Bothriocephalidce (Family II.) 

 (. Tetrarhynchidce (Family III.) 









Fia. 24. — Head of Tjenia pakadoxa, BudoVphi ; from the intestine of an oyster-catcher (Bcema- 

 topiis ostrealegus, L.) ; a, with the rosteUum partly inyaginated ; 6, end of the rostellam 

 expanded ; X 260 diam.— Original. 



TcBfbiadce. — The true tapeworms are characterised by the pos- 

 session of a small distinct head furnished with four simple oval 

 or round suctorial disks (suckers), and commonly also with a more 

 or less strongly- pronounced rosteUum (proboscis) placed at the 



