infusoria: METAMORPHOSIS of trichoda. 



461 



the latter still remaining within its cavity (m). The body thus 

 discharged (n) does not differ much in appearance from that of the 

 Oxytricha before its encystment (f), though only of about two- 

 thirds its diameter ; but it soon developes itself (o, p, q) into an 

 Animalcule very different from that in which it originated. First 

 it becomes still smaller, by the discharge of a portion of its sub- 

 stance ; numerous very stiff bristle-like organs are developed, on 

 which the Animalcule creeps, as by legs, over solid surfaces ; the 

 external integument becomes more consolidated on its upper sur- 



Fig. 242. 



Metamorphoses of Trichoda lynceus: — a, larva (Oxytricha) ; b, a 

 similar larva, after swallowing the animalcule represented at M ; 



c, a very large individual on the point of undergoing fission ; 



d, another in which the process has advanced further ; e, one 

 of the products of such fission ; f, the same body become 

 spherical and motionless ; c, aspect of this sphere fifteen days 

 afterwards ; h, later condition of the same, showing the forma- 

 tion of the cyst ; i, incipient separation between living substance 

 and exuvial matter ; k, partial discharge of the latter, with 

 flattening of the sphere ; L, more distinct formation of the con- 

 fined animal ; m, its escape from the cyst ; n, its appearance some 

 days afterwards ; o, more advanced stage of the same; p, q, perfect 

 individuals, one as seen sideways, moving on its bristles, the 

 other as seen from below ; these are magnified twice as much as 

 the preceding figures. 



face, so as to become a kind of carapace ; and a mouth is formed 

 by the opening of a slit on one side, in front of which is a sing ] e 

 hair-like filament, which is made to turn round and round with 



