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 



Order 3 



Ciliata ^^® outer part of the 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 



Flaeellata ''^^^'^'^^ "^ ^ shell and presence of a firm cortex of 



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



vibratile protoplasmic threads instead of many small ciUa, are 



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



Table of 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. 

 Garchesium. 

 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. 



^ There are several other order.s which are not mentioned here ; for an 

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

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

 Sncyclopcedia Britannica, 



