XIII, D, 5 Haughioout: Protozoa of Manila and Vicinity: I Yl'^ 



celled (or, if we accept Dobell's view, a noncellular) organism; 

 but there are many species that tend to group themselves in 

 more or less permanent colonies. Under such circumstances 

 the colony is frequently spoken of as if it were an individual. 

 However, when comparing the protozoan individual to the meta- 

 zoan individual, the tendency is to consider the entire race pro- 

 duced between successive fertilization processes in the protozoon 

 as being equivalent to the individual metazoon. This view, as 

 Dobell points out, is open to serious question. 



Whose protoplasm becomes distributed among many free living 

 cells. — In the process of reproduction, and this varies greatly 

 among the Protozoa, the original cell completely loses its indivi- 

 duality, unless we except forms where the parent cell survives 

 following a process of gemmation. As a rule, however, the 

 original cell becomes divided into two or more individuals, each 

 consisting of a portion of the protoplasm that originally con- 

 stituted the parent cell. This process goes on in geometrical 

 progression, accompanied by the usual growth phenomena, until 

 the protoplasm of the first cell has literally become distributed 

 among a large number of free daughter cells. 



These reproduce their kind by division, by budding, or by 

 spore formation. — Reproduction by division may either be by 

 binary fission, in which the parent cell divides to form two 

 daughter cells, which in time grow to resemble the parent cell; 

 or by multiple fission, in which the parent cell divides to form 

 many daughter cells, which later grow to the adult form. Bud- 

 ding involves the pinching off from the parent cell of buds of 

 nucleated cytoplasm of varying sizes according to the species, 

 the buds in time assuming the form of the parent. The parent 

 cell may or may not survive. Spore formation is often an 

 exceedingly intricate process, among the attendant phenomena 

 being the encapsulation of the organism in a resistant cyst or 

 spore case. Spore formation, in the true sense, is accompanied 

 by a fertilization process. 



The race thus formed passing through different form 

 changes. — Therein lies one of the greatest obstacles to the 

 amateur systematist in his work with the Protozoa. It brings 

 to mind the dictum of Schau'dinn, "Die Kenntniss der Entwicke- 

 lung ist das erste Postulat der Protozoenforschung," to which 

 Calkins has added: "Until the full life history is known we 

 can only place forms provisionally and with the understanding: 

 that further research alone will establish finality." The ex- 

 perienced protozoologist has little trouble in recognizing the com- 



