PROTOZOA. 



In the Infusoria the body is bounded by an external membrane, 

 and is capable of quick and varied locomotion by means of the 

 movements of the cilia, hairs, bristles, etc., which it possesses. The 

 nourishing matter may be solid, in which case it is taken in through 

 a mouth, and the remainder after digestion cast out through an anal 

 aperture (Iwlozok- nutrition), or it may lie in a fluid form as a 

 putrescent solution, in which case the name Infusoria is well applied, 

 and be taken in by simple osmosis through the walls of the body 

 (saprophytic nutrition). 



The conjugation, or fusion, of two or more individuals has been 

 observed at some period or another of the life-history in most 

 of the groups of Protozoa ; and in most groups the power of with- 

 drawing the pseudopodia or cilia and of forming stout membranes 

 round the body (encystment) to protect the organism against adverse 

 external influences is generally present. 



The Protozoa fall into three main classes. Of these the first 

 (Gijiiinoiiiij.i'd) possess the power of thrusting out processes of their 

 body as pseudopodia ; the second (Infusoria) are, for the most part, 

 without pseudopodia, but bear cilia, or flagella ; while the third 

 (Sporozoa) possess neither pseudopodia nor cilia, and are parasitic in 

 habit. 



Table .showing the classification of the Protozoa. 



CLASS I. GYMNOMYXA 



(SARCODINA). 

 Sub-class 1. RHIZOPODA. 

 Order 1. Amceboidea. 



, , 2. Testacea. 

 Sub-class 2. MYCETOZOA. 

 ,, 3. HELIOZOA. 

 ,, 4. RADIOLARIA. 



CLASS II. INFUSORIA. 



Sub-class 1. MASTIGOPHOUA. 

 Order 1. Flagellata. 



Sub-order 1. Monadina. 



,, 2. Euglcnoidea. 



,, 3. Hetcromastigoda. 



,, 4. Isomastigoda. 



,, 5. Phytomastiyoda. 



Order 2. Choanoflagellata. 



,, 3. Dinoflagellata. 



,, 4. SilicoHagellata. 



,, 5. Cystorlagellata. 



CLASS If. INFUSORIA Continvnl. 

 Sub-class 2. CILIATA. 



Order 1. Gymnostomata. 

 ,, 2. Trichostomata. 

 Sub-order 1. Aspirotricha. 

 ,, 2. Spirotricha. 



a. Heterotricha. 



b. Oligotricha. 

 '. Hypotricha. 

 d. Peritricha. 



Sub-class 3. ACINETAKIA. 



CLASS III. SPOROZOA. 

 Order 1. Gregarinida. 



Sub-order 1. Polycystidca. 

 ,, 2. Moiiocystidca. 

 Order 2. Coccidiidea. 

 ,, 3. Haemosporidia. 

 Sub-order 1. Drepanidiidea. 

 ,, 2. Acystosporidea. 

 Order 4. Myxosporidia. 

 ,, 5. Sarcosporidia. 



