RHIZOPODA. 



21 



sponge in sea-water with care and attention, it is 

 found to exhibit a constant and energetic action, 



Fig. 9. — FLINT CUYSTALS OF SI'OKGE. 



which sufficiently shows its vitality. Dr. Grant's 

 account of the discovery of this motion in a native 

 species is very interesting. 



"I put a small branch of a spongia coalita with 

 some sea-water into a watch-glass, under the micro- 

 scope, and on reflecting the light of a candle through 

 the fluid, I soon perceived that there w^as some 

 intestine motion in the opaque particles floating 

 through the water. On moving the watch-glass, so 

 as to bring one of the apertures on the side of the 

 sponge fully into view, I beheld, for the first time, the 

 splendid spectacle of the living fountain vomiting 

 forth from a circular cavity an impetuous torrent of 





"^^^^^^mi^^ 



Fig. 10.— sponge in action. 



L'quid matter, and hurhng along, in rapid succession, 



