loS PROTOPLASM 



which is placed beneath it, shows at its limit towards the 

 envelope the dark pellicle-like border, which in the absence 

 of such an enveloping layer forms the actual surface of the 

 Amoeba. In the same preparation the protoplasm with its 

 reticular meshwork can be seen most plainly below the 

 marginal layer of alveoli ; in o it is drawn as seen in surface 

 view. Round the nucleus also the layer of radial meshes 

 stands out very prominently. The great sharpness and 

 darkness of the nodal points in the framework of the meshes 

 of the endoplasm depends without doubt upon the deposition 

 here of small strongly refracting granules. 



Although the pseudopodia of Amoebae usually consist of 

 apparently structureless hyaline protoplasm, yet this is not 

 always the case. The moderately long radiating pseudo- 

 podia of A. radiosa were seen by me even in life to be 

 distinctly composed up to their extremities of a pale 

 meshwork, partly fibrous to some extent. At the ex- 

 tremities the structure becomes paler and paler, but yet 

 remains recognisable. At the same time the above de- 

 scribed marginal layer of alveoli was to be traced round the 

 whole of the pseudopodia, although its structure could not 

 be made out. A. radiosa, however, frequently passed into 

 conditions in which it exhibits large quantities of apparently 

 hyaline protoplasm. Thus it not infrequently passes from 

 the forms just described, with pseudopodia of moderate 

 length and fair thickness radiating out on all sides, into a 



O O ' 



very flat and spread out condition with spiky, pointed 

 pseudopodia, arising principally from the flat and expanded 

 margin. This margin consists of nearly hyaline protoplasm, 

 in which the meshwork structure can only be recognised with 

 difficulty. Finally, I found in the same water from which 

 the A. radiosa came, a considerable number of a small 

 Amoeba of a very peculiar form and mode of locomotion. 

 As a rule it had somewhat the form of an open fan, moving 

 with the convex edge of the fan directed forwards, and 

 formed by a fairly broad hyaline margin, upon which 

 followed protoplasm which showed a beautiful reticular 

 structure, making up the pointed end of the fan, and 

 containing the nucleus and the contractile vacuole. I 



