172 CYTOPLASMIC INCLUSIONS 



A. pro feus forms leucine and glycine crystals in the gastrioles (they are 

 therefore not strictly speaking cytoplasmic bodies), and these are then 

 separated from the gastriole and the materials are transported from the 

 crystal vacuoles to the growing refractive bodies and are there stored 

 in the form of the protein stroma of these lipoid-protein bodies. In 

 Opalina proteins are stored in the ectoplasmic segregation bodies. In 

 both these cases, the final structures are of cytoplasmic origin and al- 

 though they are so different they could perhaps be harmonized on a 

 functional basis. In Ichthyophthkius, on the other hand, the protein 

 spherules are stored and utilized in the cytoplasm, but originate in the 

 macronucleus by splitting from the chromatin a portion which contains 

 nucleic acid and iron, leaving a reserve protein in the form of large gran- 

 ules which are then discharged as completed bodies into the cytoplasm. 

 There is some evidence in the Sporozoa also of a nuclear origin of some 

 of the protein reserves, although it is entirely possible that they are 

 connected with mitochondria, since Joyet-Lavergne noted a morpho- 

 logical relationship between the two in the Sporozoa he studied. How- 

 ever, even if we disregard the somewhat questionable case of the Sporo- 

 zoa, we find that an identical function — the storage in the cytoplasm of 

 proteins — is accomplished in two cases by cytoplasmic structures, but in 

 a third case by the macronucleus. 



Digestion, except in the astomatous species, is accomplished by the 

 gastriole, a structure formed by the union of a vacuole which contains 

 the food particles with granules or vacuoles of cytoplasmic origin. In 

 Ichthyophthirius the granules involved are cytoplasmic in origin, but 

 become enclosed within the vacuole; the cytoplasmic vacuoles of ¥la- 

 hellula apparently furnish the fluid in the gastriole; while in A. proteus 

 the granules merely aggregate around the gastriole. From morphological 

 evidence, the granules in Ichthyophthirius and Flabellula are concerned 

 with all types of digestion, but in A . proteus both morphological and mi- 

 croenzymatic studies show that the mitochondria are concerned with the 

 digestion of carbohydrates and with the transport of digested materials 

 from the gastriole to such bodies as the refractive granules. There is 

 thus some variation in the digestive function, but clearer evidence of 

 differences is the fact that in both Ichthyophthirius and Flabellula the 

 diffusion of materials outward from the vacuole is accomplished without 

 the intervention of any visible granules. The granules of Amoeba, there- 



