38 



General Morphology of the Protozoa 



mainly as refractile endoplasmic bodies (Fig. 1. 18, A-C), but may be 

 found also at the surface of the pyrenoid (Fig. 1. 17, L) in chlorophyll- 

 bearing species. In addition, glycogen-like inclusions occur in Euglena 

 (22) and Peranema (23). The leucosin of Chrysomonadida (Chapter IV) 

 is stored as bodies (Fig. 4. 1, D-F) which are often relatively large. Starch 

 may be deposited as fine granules or larger bodies in Cryptomonadida, 

 Phytomonadida, and Dinoflagellida. Starch grains are deposited on the 

 inner surface of the chromatophore in Cryptomonas ovata (Fig. 1.18, H), 

 while the reserves of Chilomonns, which are composed of ^-amylose and 

 amylopectin (97), are scattered refractile bodies (Fig. 1.18, D). In Phyto- 

 monadida and Dinoflagellida, starch occurs both as scattered granules and 

 as deposits around pyrenoids. 



Glycogen, or a similar material, is common in groups other than the 

 phytoflagellates. Little is known about the chemical nature of these in- 

 clusions. Such reserves are distributed as fine granules in Paramecium 

 (186), but may be concentrated posteriorly in Stentor (222, 240). In the 

 Ophryoscolecidae, the skeletal plates (Fig. 1. 18, F, G) contain much of 

 the glycogen (155), although cytoplasmic granules may occur also (154). 

 Glycogen or paraglycogen is generally deposited during heavy feeding 

 and consumed in starvation, as traced in Stentor (222, 223). Such reserves 

 also may be deposited before encystment — as in Dileptus (207), Ich- 

 thyophthirius (156), and certain Endamoebidae — and consumed before 

 excystment. The paraglycogen of Ichthyophthirius is formed as small 

 granules within a mitochondrial sphere which disappears after the para- 

 glycogen mass reaches a diameter of 5-6[jl (156). A similar development 

 has been observed in gregarines (109), whereas glycogen is deposited in 

 association with the parabasal body of Cryptobia helicis (48). 



Lipids are probably stored by most, if not all. Protozoa, under certain 

 conditions. The accumulation of fat in Stentor has been attributed to 

 low oxygen tensions (240), and stored lipids are characteristic of old 

 rather than young cultures of Polytoma uvella (220). Lipids may be 

 distributed through the endoplasm or else concentrated in one region 

 as in Anoplophrya (51). In Stentor coernleus (223), these inclusions vary 

 from small granules to bodies as large as the macronuclear nodes. So-called 

 bodies of Maupas, believed to contain at least some lipids, occur in vari- 

 ous Cryptomonadida as two refractile ellipsoidal inclusions (88). In Ich- 

 thyophthirius, the fatty acids and glycerol which reach the cytoplasm are 

 first segregated into globules within which neutral fat is formed (156). 

 A similar process has been described in Opalina (114). 



Protein reserves have been described as basophilic granules, metachro- 

 matic granules, chromatoid bodies, albuminoid reserves, and chromidia. 

 Such reserves occur as scattered granules through the endoplasm, they 

 may be stored in peripheral globules in Opalina (115), or they may be 

 deposited as fairly large masses. Chromatoid bodies (Fig. 1,18, E), repre- 



