196 EVENINGS AT THE MICROSCOPE. 



amined. They maintain a vivacious motion, and yet at 

 the same time keep their association and the general form 

 of the column. 



Taking out a few of the dancing atoms, and isolating 

 them in this glass stage-cell, we see that they have exactly 

 the figure, appearance, and character of the young of the 

 common Cyclops ; so that you would, without hesitation, if 

 you knew nothing of their parentage, assign them to that 

 well'known genus. Their movements are almost incessant ; 

 a series of jerking progressions, performed by quick but 

 apparently laborious flappings of the limbs, right and left 

 together. They occasionally rest from their exertions for 

 a few moments, but seem to have no power of alighting on 

 any object. 



But, in order to obtain a more precise idea of the struc- 

 ture of this tiny creature, we must manage to restrain its 

 liberty a little, by applying gentle pressure with the com- 

 pressorium, just sufficient to confine it without hurting it. 

 The body is inclosed in a broad carapace, shaped much 

 like a heraldic shield, but very convex on the back, and 

 terminating behind in a slender . point or spine, which is 

 cut into minute teeth along the edges. Below this shield 

 is seen the body, with three pairs of legs, a great proboscis 

 in the middle pointing downwards and backwards, and the 

 anal fork, which consists of a bulbous base and two diverg- 

 ing points, which project behind under the spine of the 

 shield. 



The legs are exclusively swimming organs ; they have 

 no provision for grasping, no claws or hooks, nor do they 

 appear to be capable of being used for crawling on the 

 ground or for climbing among the sea-weeds. They are 

 fringed along one edge with long and stout, but somewhat 

 flexible, spines, of which those that are nearest the trunk 

 seem more rigid, and are directed more at right angles to 

 the limb than the rest. The legs are formed of many 

 imperfect joints, and the second and third pairs are 



