94 PROTOZOA. 



At any time Vorticella is capable of breaking free from its stalk and 

 swimming away, and it can also encyst, in which condition it may, like 

 Amceba^ experience considerable vicissitudes with impunity. 



Conjugation is effected by one individual setting free by budding a 

 number of small buds which acquire a second band of cilia and swim away. 

 One of these settles upon another individual and interchange of 

 nuclear material is effected. The bud is said to then atrophy, the total 

 result being the transfer of nuclear material from one individual to 

 another. In this respect the conjugation of Vorticella more nearly re- 

 sembles the sexual reproduction of Metazoa. 



Vorticella belongs to the same class as Paramceciuin ( Ciliata) but 

 to the order Peritricha, the cilia being confined to a ring around the 

 mouth. 



IV.— GREGARINA. 



Sub-Kingdom . . . . Protozoa. 



Phylum Corticata. 



Class Sporozoa. 



Gregarina blattarum is a small animal found in 

 part of the intestine (the mesenteron) of the common 



H bit Cockroach {Blattd). Hence it is an endopara- 

 site. Its body is elongated and has a definite 

 shape. In the protoplasm there can be discerned an outer 

 cortex which appears to be more or less contractile and an 

 inner more fluid medulla. The cortex secretes a thin cuticle 

 Structural ^^^^^ envelopes the body. At one end, usually 

 regarded as the anterior end, the cuticle is 

 thickened into a cap with a rim of hooks. At about one- 

 third of the length of the body from the anterior end, the 

 cuticle extends a as thin septum or partition across the 

 protoplasm, dividing the body into an anterior proio77ierite 

 and a posterior deutomerite. In the medullary substance 

 of the deutomerite is an oval nucleus and occasionally there 

 can also be seen a small nucleolus. 



There are no cilia nor pseudopodia and the animal can 



progress only slowly by a creeping movement of the cortex. 



.,.^^^.„^ There is no mouth nor anus, and no solid food 

 Alimentary. i i i ^ , . , ^ 



passes mto the body of the animal. Gregarina 



is, from its habitat, surrounded on all sides by soluble and 

 diffusible proteids which have been prepared by its host, the 

 cockroach, for its own use. These are absorbed by Gre- 

 garina through the cuticle as required. There appears to 



