59 



Can these. Spores or Pseudonavicellce develop further in the 

 Earthworm ? 



No ; they require to be transmitted to another host. 



How is transmission to another Earthworm effected ? 



Probably the earthworm is eaten by a bird. The resistent- 

 coated spores (undigested) are thus set free, and passing 

 out through the food canal they are scattered over the 

 ground. The spore may be swallowed by an earthworm 

 along with its food ; and the coat being dissolved by the 

 digestive juice, the contained sporozoites are consequently 

 liberated. 



How would the Sporozoite get into the Reproductive Organs ? 



It is active and can bore through tissues. It might pass 

 through the intestine wall and via the body cavity, or more 

 likely by some blood channel, reach its objective, the 

 seminal vesicles. 



When the Sporozoite gets inside a Seminal Vesicle, what 

 does it do ? 



It enters a sperm- mother- cell (sperm-morula) and there 

 develops into a young trophozoite. 



Conjugation is said to be Anisogamous in Monocystis. 

 What do you understand by the Terms Isogamous 

 and Anisogamous ? 



Isogamous means that the conjugating gametes are 

 not different. Isogamy is common among Flagellates, 

 e.g., Copromonas. Isogamous conjugation may be tem- 

 porary ; in which case no zygote is formed, but an ex- 

 change of nuclear substance is effected. This is seen in 

 Ciliata, e.g., Paramecium. 



When the gametes are distinct (male and female), the 

 conjugation is described as anisogamous, e.g., Volvox, 

 many Sporozoa, and all Metazoa. 



