694 GEOFFREY LAPAGE 



that the amoel)ae in the culture were all feeding principally 

 upon diatoms. Endogenous buds, when they are formed in other 

 groups of Protozoa, are invariably free from food vacuoles until 

 after they are born, and it is indeed difficult to imagine how they 

 could obtain any solid food until they are set free. Even if 

 we adopted the fantastic view that, in the case under considera- 

 tion, the spheres had obtained the diatoms from the amoebae 

 in which they lay, it is imi)ossible to explain how they did so, 

 seeing that a vacuole tilled with tluid lay between them and the 

 protoplasm of the amoebae. The presence of that vacuole is, 

 of course, in itself no argument against their being endogenous 

 buds, since most endogenous buds develop inside a cavity or 

 ' l^rood chamber ' in the parent. 



A still more significant detail is, however, the observation, 

 made upon the living object, that, when the sphere was 

 extruded, the remains of diatoms might be extruded with it 

 from the same vacuole. This can only mean that the diatoms 

 were taken up at the same time as the sphere, a fact which is 

 easy to understand when we remember that the amoebae 

 were feeding mostly in the clumps of diatoms and debris in 

 the culture rather than in the open. The vacuoles in which the 

 spheres lay were, therefore, true food vacuoles and not of the 

 nature of ' brood chambers *. This does not prove, of course, 

 that they were not buds, since the amoebae were seen to ingest 

 the free spheres, and it might be argued that the spheres were 

 no less true buds because their parents were eating them. 

 But, taken in conjunction with the absence of any evidence 

 of the mode of formation of buds and the presence of food 

 vacuoles in their cytoplasm, it is a very significant piece of 

 evidence. 



Another observation pointing in the same direction is the 

 fact that the spheres were not always perfectly spherical, 

 but were often irregular in shape and, indeed, w^ere, in some 

 cases, seen to undergo form changes while inside the amoebae 

 (cf. p. 686, supra). Tliis strikingly suggests that they were 

 amoebae which had been ingested. 



The hypothesis of endogenous budding breaks, however, on 



