352 



EVENINGS AT THE MICROSCOPE 



revolving circle. The effect, however, is exactly the 

 same: that of paddling the beautiful little globe vigor- 

 ously through the water. The prismatic colors are pro- 

 duced by the play of light on their glittering surfaces, 

 which are ever presented to the eye of the beholder at 

 changing angles. 



We rarely see these rows of paddle-fins wholly at rest, 

 but occasionally one or two bands will be alone in a state 



CYDIPPE. 



of vibration; or one or more will suspend their action 

 while the rest are paddling. Sometimes in a band that is 

 at rest, a minute and momentary wave will be seen to run 

 rapidly along its length. All these circumstances show 

 that the ciliary motion is perfectly under the control of 

 the animal's will, not only in the aggregate, but in every 

 part. 



In an excellent memoir on this animal by Mr. K. Pat- 

 terson of Belfast, 1 there are some interesting observations 

 on the power of its tissues to become tinged with extra- 



1 "Trans. Roy. Irish. Academy," vol. xix. pt. 1. 



