436 EVENINGS AT THE MICROSCOPE 



CHAPTER XXI 



INFUSORIA 



R EVEN ON S & nos moutons. We will resume our 

 examination of the drop of pond- water and the 

 fragments of Myriophyllum which have been wait- 

 ing for us in the live-box. 



Our attention then shall first be given to some elegant 

 creatures of a brilliant translucent green hue, which are 

 gracefully gliding about. .They are of the genus Euglena, 

 so called because each is furnished with a very conspicuous 

 spot of a clear red hue, situated near the head, which 

 Ehrenberg, on account of its resemblance to the lowest 

 forms of eyes in the Rotifera, that are somewhat similar in 

 color and appearance, pronounced to be an organ of vis- 

 ion. More recent physiologists, however, doubt the cor- 

 rectness of the conclusion. 



The animals are of several kinds. The most numerous 

 is an active little thing of about ^th of an inch in length 

 when extended, though from its extreme versatility it is 

 as difficult to assign to it a definite size as a definite 

 shape. It seems to be the E. sanguinea, so called because 

 it is said to occur sometimes of a deep red hue, and in such 

 vast profusion, as to give the waters the appearance of 

 blood. I have never seen it, however, other than as it 

 now appears, rich emerald green in the body, with the two 

 extremities perfectly clear and colorless. I might perhaps 



