PROTOZOA 



Economic Importance of Protozoa* 



Negative 



45 



From the Tertiary deposits of the Barbadoes, Ehrenberg described 

 278 species of Foraminifera, known today. 



We consider the Protozoa as the most primitive forms of animal 

 life. Certain forms are so closely allied to the plants that they can 

 scarcely be claimed exclusively by zoologists. 



The Sarcodina form an ascending series from the Lobosa, with 

 no skeleton, up to the Radiolaria, which have well-developed 

 skeletons. The Mastigameba is a Flagellate with pseudopodia, and 

 we might consider it a connecting type between the two classes of 

 Protozoa. The fact that Porifera have collar cells, somewhat 

 resembling the flagellated protozoa, has led some zoologists to sug- 

 gest the evolution of Choanoflagellata into Sponges. Kofoid finds 

 in the colonial Dinoflagellata^ with nettling organs and eye spots, 

 relationships to the Coelenterata. 



1 Negri bodies were at one time classed as Sporozoa, and later as Sarcodina, but 

 they are now grouped with various other inclusions of diseased cells, such as in tra- 

 choma, and sprue, as Chlamydozoa, or "mantle-covered" animals. Cowdry has even 

 questioned whether the granules are microorganisms. Hurst suggests (Lancet, Sept. 

 19, I931, p. 622) t\i3it rabies may have been transmitted in certain Trinidad cases from 

 humans to cattle, by vampire bats. See also Knutti, R. E., 1929, Jour. Amer. Med. 

 Assoc, vol. 93, p. 754. 



