PART III. 

 PROTOZOA. 1 



CHAPTEK XXXVII. 



CLASSIFICATION AND GENERAL CHARACTERISTICS. 



ALL animal forms consisting throughout their entire life of a single 

 cell or of a colony of single cells are called protozoa. 



They are so closely related to the protophyta, or lowest plant forms, 

 on the one side, and the metaphyta, or many-celled animals, on the other, 

 that it is difficult to mark out a sharp line of distinction between 'them. 



In general, it may be said that each cell consists of protoplasm which 

 is differentiated into nucleus and cytoplasm, both parts showing many 

 variations in the several groups, and that each cell undergoes a more 

 or less complicated life cycle, appearing in different forms at different 

 stages of development. 



Doflein, in Kolle and Wassermann, gives the grouping of the protozoa 

 as follows: 



PHYLUM: PROTOZOA. 



I. Subphylum: Plasmodroma. Doflein. 

 I. Class: Rhizopoda. v. Siebold. 



I. Order: Amcebina. Ehrenberg. 

 II. Order: Heliozoa. Haekel. 



III. Order: Radiolaria. Johannes Miiller. 



IV. Order: Foraminifera. d'Orbigny. 

 V. Order : Mycetozoa. de Bary. 



II. Class: Mastigophora. Diesing. 



I. Subclass: Flagellata. Cohn em. Butschli. 



I. Order: Protomonadina. Blochmann. 

 II. Order: Polymastigina. Biitechli and Blochmann. 



III. Order: Englenoidina. Klebs. 



IV. Order : Chromomonadina. Blochmann. 

 V. Order: Phytomonadina. Blochmann. 



II. Subclass: Dinoflagellata. Biitschli. 

 I. Order : Adinida. Bergh. 

 II. Order: Dinifera. Bergh. 

 III. Subclass: Cystoflagellata. 



Appendix: Trichonymphidae. Leidy. 



1 The following general authorities on protozoa have been consulted freely in this work : Doflein 

 and Prowazek, in Kolle and Wassermann ; Minchin, in Ray Lankester ; Calkins. 



