ACTINOPHRYS. 47 



stupefied; the pseudopodium then either gradually retracts, or, as 

 I have frequently seen, suddenly, and as if it were a rubber 

 thread under high tension abruptly cut loose at one end, jerks 

 the prey toward the body. At the same time the neighboring 

 pseudopodia bend over the victim and form a sort of cavity (r 1 ) 

 about it, and then the surface of the body rises on each side and 

 gradually engulfs the living morsel, which by this time shows 

 but little signs of life. In a short period it is passed through the 

 cortical layer of cells to the interior, and there undergoes diges- 

 tion in a fluid which seems to be generated, in a cavity between 

 the cells, for each special body that is introduced. 



As yet we have not arrived among those animals which 

 possess a distinct mouth, but the food is introduced at any point 

 of the body which corresponds to the interspaces of the cells ; 

 and likewise when the digestible parts of the prey are extracted, 

 the refuse is ejected at any spot in the circumference. There is 

 also a tendency toward a circulation of fluid, most especially 

 exhibited in the pseudopodia ; but it is more apparent than real, 

 and requires the most careful scrutiny to detect the actual state 

 of things. The minute transparent granules that more or less 

 abound in the cytoblastema, and particularly in the pseudopodial 

 prolongations (/), are the only means by which we are enabled 

 to descry the movement of this tissue at any particular point; and 

 as they are borne along in dilations, extensions, or retractions of 

 the various regions of this glairy substance, they appear to be 

 floating in streams of fluid, whereas their motions are really 

 limited to the extent of the expansibility or contractility of 

 the cytoblastema. 



There is, however, in certain parts of the body, a more re- 

 liable exhibition of an incipient fluid circulation. Among the 

 large cells of the cortical layer, one or two of them (cv) exhibit 

 a tolerably regular but slow expansion and dilatation, like the 

 diastole and systole of the so-called heart, or contractile vesicle, 

 of the higher Infusoria, which I shall speak of presently. In 

 what manner these vesicles are connected with the clear fluid 

 with which they fill themselves, when they expand, or through 



