THE PAGE OF NATURE. 



135 



and which proceed, we must believe, from infinite wis- 

 dom. The Zygnemas form the principal fresh-water 

 alga? of India, occurring in pools and streams in the 

 central districts, as well as among the Himalayas. They 

 ascend as high as 15,000 feet on these mountains, 

 forming cloudy masses in the ice-cold springs which 

 trickle from the edges of glaciers. 



There is a very remarkable class of confervse called 

 OscillatoriaB, on account of the singular oscillating motion 

 observed in the filaments by various naturalists, thus 

 connecting them apparently with the animal kingdom; 



.j/ S's-a-t 



FlO. 19. OSCILLATORIA N1GKA. 



the power of voluntary motion being one of the chief 

 characteristics essentially distinguishing animal from 

 vegetable life. These Oscillatorise grow in masses of fila- 

 ments based on a mucilaginous substance, the remains 

 of old dead individuals deprived of their colour and 

 agglutinated together, the whole emitting a strong odour 

 of sulphuretted hydrogen which is extremely disagreeable, 

 and sometimes causes severe headache. They have been 

 found in a great variety of situations, ascending as high 

 as 17,000 feet, or even 18,000 feet on the Himalayas. 



