WHEEL-BEARERS. 241 



siderable swiftness through the water, turning frequently 

 on its course, and often partially revolving on its long axis. 

 When inclosed, as is often the case, by two fragments of 

 the filamentous Chara, it travels along the sides of its in- 

 closure, nibbling, as it goes, the flocculent and sedimen- 

 tary deposits on the surfaces of the leaves. The long 

 spine-foot is commonly carried inertly after it ; when the 

 animal suddenly turns, of course the tail is bent at the 

 basal joint, but it is not habitually whisked about, as is 

 the tail of Brachionus, nor is it so much used as a support 

 or turning point. The animal has the power of so using 

 it, however, and of adhering with considerable force to the 

 glass of the box, or the side of a phial by its point. 



We have hitherto looked at our Rotifera by transmitted 

 light, and their crystalline transparency renders them beau- 

 tiful objects when thus exhibited. But we will now look 

 at the Whiptail by the direct light of the sun upon it, 

 condensed, but not to a burning point, by the bull's-eye 

 lens. 



It now possesses a peculiar beauty of another character. 

 The body generally is colourless as a vase of glass, but 

 reflects the rays brightly from its polished surface. An 

 advancing egg in the ovary is opaque white, as is the front 

 part of the mastax ; the stomach and intestine filled with 

 vegetable matter are of a yellow green ; the rotating head 

 appears of a pale blue, and the eye shines out as a speck 

 of opaque vermilion. 



With the dipping-tube I will now take up a drop of 

 water from the bottom of the Chara-jmr, allowing a little of 

 the loose sediment to flow in also. This is a random cast ; 

 we know not what we may get, though we are pretty sure 

 to catch something. Now then for the examination. Ha ! 

 here is the curious Skeleton Wheel-bearer, Binocharis 

 pocillum ; — nay, several of them. 



This genus is remarkable for possessing true joints in 

 the foot ; not merely telescopic inversions of the skin, but 



K 



