738 MICROSCOPIC FORMS OF ANIMAL LIFE PROTO/OA 



but it is supplied with nourishment by tJie instrumentality of its 

 pseudopodia, its food being derived not merely from vegetable par- 

 ticles, but from various small animals, some of which (as the young of 

 Entomostraca) possess great activity as well as a comparatively high 

 organisation. When one of these happens to come into contact with 

 one of the pseudopodia (which have firm axis-filaments (ax) clothed 

 with a granular sarcode), this usually retains it by adhesion ; but the 

 mode in which the particle thus taken captive is introduced into the 

 body differs according to circumstances. If the prey is large and 

 vigorous enough to struggle to escape from its entanglement, it may 

 usually be observed that the neighbouring pseudopodia bend over and 



FIG. 573. Actinophrys sol : A, figure showing the wide vacuolated cortical 

 layer or ectosarc (B) and the fine granulated endosarc (M) ; n, central 

 nucleus, ax, axial filaments of pseudopodia ; cv, contractile vacuole ; N, food- 

 mass inclosed in a large food-vacuole. B, a colony of four individuals, after 

 treatment with acetic acid ; K, M, and N, as before ; v, v, vacuoles. C, a cyst ; 

 z, r, outer and inner envelopes. D, a burst .cyst from which the young is 

 escaping, though still inclosed by the inner envelope. (From Biitschli, 

 after Grenadier, Stein, and Cienkowsky.) 



apply themselves to it, so as to assist in holding it captive, and that it 

 is slowly drawn by their joint retraction towards the body of its 

 captor. Any small particle not capable of offering active resistance, 

 011 the other hand, may be seen after a little time to glide towards 

 the central body along the edge of the pseudopodium, without any 

 visible movement of the latter, much in the same manner as in Gromia. 

 "When in either of these modes the food has been brought to the 

 surface of the body, this sends over it on either side a prolongation of 



