INFUSORIA. 898 



claret-bottle or an oil-flask ; the muzzle being broadly 

 truncate or even indented. 



Its motion is rapid : a swift gliding in the direction of 

 its long axis ; it turns continually on the same axis, which 

 gives a waving irregularity to its course, and has a pretty 

 effect from the continual crossing of the flutings in the 

 revolving. This specimen is about y^th of an inch in 

 length, including the tail. 



Euglena deses is much larger, being about u^th of an 

 inch in length, though the tail is very short. It has a 

 thick body, with a round, blunt head ; it tapers suddenly 

 to the tail. Its colour is bright green with a red eye ; 

 but the presence of an infinite number of irregular oblong 

 granules and lines with several globular vesicles, gives an 

 opacity and a blackness to its appearance. In its manners 

 it is sluggish; it never swims or glides gracefully and 

 swiftly among its playful companions, but contents itself 

 with twining slowly among the downy stems and filaments 

 of the water-plants, or crawls upon the surface of the live- 

 box. It does not appear to change its form, otherwise 

 than its soft and flexible body necessitates, as it twines 

 about. 



But enough of the Euglenas. For I have just caught 

 sight of a much more curious creature, the Swan Animal- 

 cule (Trachelocerca olor). It is reposing on one of the 

 leaves of the Myriophyllum, its long and flexible neck 

 lengthening and contracting at pleasure, the tip thrown 

 about in quick jerks in every direction, somewhat like a 

 caterpillar when it touches several points impatiently with 

 its head. 



If we admire the graceful sailing of a swan upon a lake, 

 the swelling of its rounded bosom, the elegant curves of 

 its long neck, we shall be struck with the form and motion 

 of this animal. The form has much resemblance to that 

 of a swan, or still more to that of a snake-bird (Plotus) ; 

 the body, swelling in the middle, tapers gradually into a 



