LATTICE WORKERS, OR POLYCYSTINA. 77 



points still remains very obscure. All that is need- 

 ful for the present purpose may be contained in a 

 brief summary : " The Actinophrys seems to have 

 little or no power of moving spontaneously from 

 place to place, and it obtains its food entirely 

 through the instrumentality of its pseudopodia, 

 which, by their peculiar adhesive property, attach 

 themselves to bodies that come into contact with 

 them. Not only motionless particles of vegetable 

 matter, but actively-moving Infusoria are thus en- 

 trapped. When 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 apply themselves to the 

 captive body, so as to assist in retaining it, and that 

 it is slowly drawn by their joint retraction towards 

 the body of the Actinophrys. In other cases, how- 

 ever, the captive seems as if it were paralysed by 

 the contact of the pseudopodium, remaining mo- 

 tionless for some seconds, and then, without any 

 visible movement of its captor, gliding either slowly, 

 or rapidly in a centripetal direction, along the 

 margin of the pseudopodium to which it adheres, 

 until it becomes jammed, as it were, between the 

 base of this and a neighbouring one. It is usually, 

 in fact, by thus gliding along the margin of the 

 pseudopodium, as if propelled by an invisible peri- 

 staltic contraction of its sarcode, rather than by a 



