DISTOMUM. 143 
Distomum is a type of the Digenous Trematoda, or those 
with two or more generations in their life-cycle, which 
alternate in their environment between two hosts, as in 
Fig. 76.—A CERCARIA. 
Fig. 77.—CERCARIA AND 
DisToMuUM. 
Encysted Cercaria. 
(The structure can still be seen 
through the cyst.) 
nye 
Young Distomum. 
_ Notice tail, suckers, bilobed 
intestine and dotted cysto- 
genous cells. 
Distomum. It also illustrates several adaptations due to 
a somatic endoparasitic habit (see Chapter IX.). The high 
fecundity, the complex sexual organs, and the absence of 
sense-organs should be here noted. 
