THE PROTOZOA 



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having in it a special foramen or aperture, through which the 

 protoplasm can emerge. There may be one main aperture only, 

 or there may be many smaller ones as well, and so we sub-divide 

 the order Foraminifera into the Perforata those with many 

 perforations besides the main aperture and the Imperforata with 

 one main aperture but no small perforations. 



Those Protozoa which have no shell, but in which 



Ciliata ^ e Ollter P art f tne protoplasm is rather denser than 



the inner, so forming a cortex (see Vorticella, p. 14), 



and which have also a band or uniform covering of cilia, are known 



as the Ciliata. This order contains many most beautiful forms, 



common in pond water. 



Finally, those which are like the Ciliata in the 

 a ^ sence f a sne ^ an d presence of a firm cortex of 

 protoplasm, but which have only one, or a few, large 

 vibratile protoplasmic threads instead of many small cilia, are 

 known as the Flagellata (Latin flagellum, a whip). 1 



Flagellata 



TABLE OP CLASSIFICATION OF GENERA 

 Group PROTOZOA. 



Order I. LOBOSA. Genus Amoeba. 

 Order II. FORAMINIFERA. 



Sub -order 1. Imperforata. Genus- 



Sub-order 2. Perforata. Genera - 



Miliolina. 

 Textularia. 

 Nodosaria. 

 Lagena. 

 Globigerina. 

 Calcarina. 

 Pulvinulina. 



Order III. CILIATA. 



( Vorticella. 

 -! Carchesium. 

 Zoothamnium. 



Sub-order 1. Peritricha Genera 

 (those with a single 



band of cilia). 

 Sub-order 2. Holotricha Genus Paramoecium. 



(those wholly 

 covered with cilia). 



Order IV. FLAGELLATA. Genus Bodo or Hetero- 



mita. 



1 There are several other orders which are not mentioned here ; for an 

 account of these, and for pictures illustrating the large variety of forms amongst 

 the Protozoa, see the article "Protozoa," by Professor Ray Lankester, in the 

 Encyclopaedia Britannica. 



