272 EVENINGS AT THE MICROSCOPE 



off and show you another elegant little creature, the Whip- 

 tail (Mastigocerca carinata). I have here in a bottle some 

 stalks of the Water-Horsetail (Chara vulgaris), which I 

 obtained in a pond a few weeks ago. These I examine 

 in this way. Taking hold of the Chara with a pair of 

 pliers, I pull it partially out of water, and, allowing it to 

 rest on the neck of the bottle, I cut off with a pair of 

 scissors, or with a penknife on my nail, about one-fourth 

 of an inch of the tips of three or four leaves, which ad- 

 here together by their wetness. These tips I place in the 

 live-box with a drop of water, and having separated them 

 with a needle, I put on the cover, and examine them with 

 a triple pocket lens; holding np the box perpendicularly, 

 not opposite the light, but obliquely, so that the field is 

 dark; but the light reflected and refracted by the animal- 

 cules shows them out beautifully white and distinct, even 

 the minute ones. The forms and some characters of the 

 middling and larger can be quite discerned thus; for ex- 

 ample, the slender tail of the one I am now going to 

 show you I can thus see. The position of any particular 

 individual to be examined being thus marked, it is read- 

 ily put under the object-glass of the microscope. I have 

 found these leaves very productive of the more stationary 

 animalcules, the Hotifera especially. 



It was in this way I this morning found the pretty and 

 delicate little Whiptail, which I am going to make the 

 subject of oar evening's study. It is enclosed in a glassy 

 shell (lorica) of a long oval form, from which rises on the 

 front half of the back a thin ridge which in the middle 

 has a height nearly equal to half the diameter of the 

 body, but tapers off at each end. Its base is corrugated 

 with wrinkles. This is not set on symmetrically, but 



