414 H. W. KING ON AMCEB^. 



and means of obtaining food, and by the agency of wading birds 

 unconsciously conveying small particles of mud containing these 

 Amoeba, adhering to their feet, from one pond to another, and so 

 diffuse them from island to island. It is a well-known fact that 

 wading birds migrate great distances, and they are, no doubt, great 

 distributors of microscopic aquatic life. 



Amoeba radiosa is a very special form, and moves about with its 

 long rigid pseudopodia that often act as adhesive disc -like feet 

 (Fig. 5, g.g.^ PI. XIX.) on the glass and cover-glass, and seem to 

 partially draw the animalcule along, and sometimes the Amoeba is 

 suspended, fixed by one of these pseudopodia, and may turn, as on 

 a pivot, partially round. Evidently this form has here differentiated 

 a special attribute at the extremities of the pseudopodia. This 

 action seems to be the first exemplification in Amoeb£e of another 

 attribute, the endowment of a pseudopodium with powers of disc- 

 like attachment, the action of which is distinct from a gliding 

 movement or a mere travelling motion, such as is commonly to be 

 seen in this and other forms, and which has become a co-ordinate 

 attribute of the organism. 



In the same dipping with Amoiha endo-divisa from Colon were 

 very active specimens of Amoeba princeps (Fig. 7, PI. XIX.) asso- 

 ciated with this new form, and with which their more vigorous, 

 deeper coloured, and powerful digestive protoplasm contrasted. 

 As usual with these Amoeba they are formed of very distinct pro- 

 toplasms.* The more solid and internal endosarc is of a very 

 deep yellow ochre colour, very much deeper in hue than in those 

 specimens I have seen inhabiting waters in this country. The 

 ectosarc is of a pale straw tint, yet this, too, shared a deeper hue. 

 The colours are evidently liable to vary, influenced, as they no 

 doubt are, by food and the diversified action of widely different 

 regions upon them. 



* Some observers argue that Amoebae have but one protoplasm indepen- 

 dent of nucleus, because the whole protoplasm stains alike, whereas stain- 

 ing does not show attributes, but form only. No one would suggest 

 that woody fibre cells, secreting cells, and cellular tissue had only the same 

 attributes, yet these in many plants all stain one colour, while these cells 

 exemplify different attributes that imply in each special protoplasmic 

 growth. In the "Proceedings of the Royal Society," vol. xlix, p. 194, Nature 

 of Amoeba, " Contrast of the protoplasm of cell to that of the pseudopodia, 

 the former exhibits, according to focus, a finely punctuated or reticular 

 aspect, whilst the pseudopodia exhibit not the faintest trace of structure— 

 they behave different to stainiug reagents. The protoplasm of an amoeboid 

 cell, as of the white blood corpuscle, may be regarded as composed of two 

 distinct substances, spongioplasm and hyaloplasm." 



