PSEUDOPODIA. 153 



the slightest evidence of the crawling movement which 

 they are reputed to exhibit." In those of the European 

 seas, however, these powers have been seen by too 

 many accurate observers, to leave the slightest doubt of 

 the facts. I have myself kept some of the more familiar 

 British forms in aquaria for months, and have seen 

 them crawling every day (especially by night) over ah 1 

 parts of the vessel and its contained sea-weeds. It 

 may be that Mr Macdonald, pursuing his researches 

 on ship-board, was not able to afford his specimens 

 the continuance of absolute stillness, which is essen- 

 tially indispensable to their activity. 



The sustenance of these simple bodies is secured by 

 the enveloping and adhering powers of the sarcode. 

 The pseudopodia are food-gatherers as well as instru- 

 ments of locomotion. They explore the vicinity of 

 the animal, feeling about in all directions ; any ani- 

 malcule, or simple plant, more minute than them- 

 selves ; any stray Diatom, or Desmid, or Alga, or 

 Infusorium, or embryo Mollusk, or Sponge-gemmule ; 

 or any particle of decomposing organic matter, touched; 

 is instantly entangled and laid hold of by these vis- 

 cous hands : the sarcode envelopes and covers it, and 

 then, contracting, draws it into the interior, where it 

 may sometimes be followed by the eye, through the 

 transparency of the shell. There is no mouth, no 

 stomach, no digestive canal ; but the homogeneous 

 jelly appears to have the power of assimilating the 

 nutrient juices of the food in any and every part alike; 

 and hence it is of no consequence what part of the 



