PHYSIOLOGY 107 



carbohydrate metabolism of the organism, since their number was 

 proportionate to the amount of food obtained by the organism. 

 Veley (1905) on the other hand found them albuminoid in nature. 

 Studies of the refringent bodies in Amoeba proteus led Mast and 

 Doyle (1935, 1935a) to conclude that the outer layer is composed of 

 a protein stroma impregnated with lipid containing fatty acid, which 

 gives positive reaction for Golgi substance; the envelope is made up 

 of a carbohydrate which is neither starch nor glycogen; and the re- 

 fringent bodies function as reserve food, since they disintegrate dur- 

 ing starvation. The same function was assigned to those occurring in 

 Pelomyxa carolinensis by Wilber (1945, 1945a), but Andresen and 

 Holter (1945) do not agree with this view, as they observed the 

 number of the refringent bodies ("heavy spherical bodies") remains 

 the same in starvation. Thus a full comprehension of the nature and 

 function of the refringent body must depend on future observations. 



The indigestible residue of the food is extruded from the body. 

 The extrusion may take place at an}' point on the surface in many 

 Sarcodina by a reverse process of the ingestion of food. But in pelli- 

 cle-bearing forms, the defecation takes place either through the 

 cytopyge located in the posterior region of the body or through an 

 aperture to the vestibule (Fig. 37, b-d). Permanent cytopyge is lack- 

 ing in some forms. In Fabrea salina, Kirby (1934) noticed that a large 

 opening is formed at the posterior end, the contents of food vacuoles 

 are discharged, and the opening closes over. At first the margin of 

 the body is left uneven, but soon the evenly rounded outline is re- 

 stored. The same seems to be the case with Spirostomum (Fig. 38), 

 Blepharisma, etc. Cytopyge (Klein, 1939). 



Holophytic (autotrophic, prototrophic) nutrition. This is the type 

 of nutrition in which the Protozoa are able to decompose carbon 

 dioxide by means of chlorophyll contained in chromatophores (p. 89) 

 in the presence of the sunlight, liberating the oxygen and combining 

 the carbon with other elements derived from water and inorganic 

 salts (photosynthesis). Aside from the Phytomastigina, chromato- 

 phores were definitely observed in a ciliate Cyclotrichium meunieri 

 (Figs. 300, o; 301) (Powers, 1932; Bary and Stuckey, 1950). In a 

 number of other cases, the organism itself is without chromatophores, 

 but is apparently not holozoic, because of the presence of chloro- 

 phyll-bearing organisms within it. For example, in the testacean 

 Paulinella (Fig. 206, c) in which occur no food vacuoles, chromato- 

 phores of peculiar shape are always present. The latter appear to be 

 a species of alga which holds a symbiotic relationship with the 

 testacean, and perhaps acts for the sarcodinan as the chromatophores 



