074 GEOFFREY LAPAGE 



These were nucleated, spherical bodies, with a sharply-defined 

 outline, whose protoplasm resembled that of the amoebae 

 themselves. They would, indeed, have been almost indistin- 

 guishable from the amoebae containing them had they not been 

 in some cases enclosed in a v«!ry obvious vacuole, the margin 

 of which was very distinct. Between the enclosed body and 

 the margin of the vacuole was a space, varying in extent 

 in different cases (cf. PI. 28, figs. 2 and 5 ; PI. 29, figs. 9, 10, 

 and 11), which was pinkish in colour and presumably contained 

 fluid. 



The diameter of the spheres varied between 8-46-5 //, both 

 these figures representing extreme sizes. The majority of them 

 varied between 20-26 /x. They were very distinct and well- 

 marked objects, much larger than the ordinary food vacuoles. 

 In certain positions of the amoebae, however, when the endo- 

 plasni was packed with food or when the protoplasm, in the 

 course of its streaming, became heaped up over the sphere, 

 the latter became very indistinct. This was especially the case 

 in the rare examples in which the vacuole round the sphere 

 was narrow. It was then difficult to determine the exact line 

 of demarcation between the enclosed sphere and the surrounding 

 protoplasm. On such examples it is quite possible for an inex- 

 perienced worker to mistake the spheres, in spite of their large 

 size, for the nucleus, a point to which we shall return later 

 (cf. below, p. 690). 



In stained preparations the spheres showed a typical vesicular 

 nucleus, exactly similar in structure to the nucleus of the 

 amoeba itself, consisting, that is to say, of a central endosome 

 with a meshwork structure, surrounded by a clear halo, free 

 from chromatin and apparently structureless. Here again, 

 as in the amoeba, no definite nuclear membrane could be made 

 out. The whole nucleus of the sphere, including the clear halo 

 round the endosome, measured from 6-8 /i, and the endosome 

 itself from 4-5 A'. 



Since the measurements were made from stained preparations, 

 in which some shrinkage may have occurred, the actual size 

 may have been rather larger than this, although very Uttle 



