INFUSORIA. 389 



CHAPTER XXT. 



INFUSORIA. 



We will now resume our examination of the drop of 

 pond-water, and the fragments of Myriophyllum, which 

 have been waiting 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 conspicu- 

 ous 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 colour and appearance, pronounced to be an organ of 

 vision. More recent physiologists, however, doubt the 

 correctness of the conclusion. 



The animals are of several kinds. The most numerous 

 is an active little thing of about T ^ of an inch in 

 length when extended, though from its extreme versa- 

 tility 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 y 

 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 

 colourless. I might, perhaps, describe its ordinary form 

 as spindle-shaped, with a pointed tail, and a blunt, 

 rounded head ; but it is remarkable for the variableness 

 of its shape. It is capable of assuming an appearance 



